Browse Topic: Occupant protection

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Impact of Harness Integrated Crash RestraintsF-0081-2025-02705/20/2025
The Crashworthy and Escape Systems Branch at NAWCAD has been developing an integrated restraint harness concept for several years, with the intent of developing a novel method of providing improved occupant protection in a crash scenario. A series of tests was conducted on the Horizontal Accelerator at NAS Patuxent River to evaluate the performance of the prototype integrated-restraint system under MIL-STD-58095 conditions with the 50th percentile male Hybrid III Anthropomorphic Test Device (ATD). While occupant flail was the primary metric being analyzed in this effort, ATD instrumentation was also captured, showing that the integrated restraint system demonstrated a significant reduction in head flail compared to five-point restraints while maintaining injury criteria within acceptable levels.
Anderson, Eric, Minnich, Shannon
REDUCED ORDER MODELLING METHOD (ROMM) FOR GROUND VEHICLE ROLLOVER PROTECTION M&S2024-01-390311/15/2024
ABSTRACT The performance of ground vehicles during a rollover event is an important safety and occupant protection requirement for military vehicles. Modeling and simulation is a very useful tool in study and investigation of vehicle rollover characteristics and countermeasure concepts. This study presents two methods of simulating the rollover events. The first one uses Full System Method (FSM), where all the components are modelled as is and are evaluated. The second method is a reduced order modelling method (ROMM) using integration of the resulted kinematics data from FSM into the vehicle model with occupant & restraints. The FSM & ROMM methods were applied to simulate two HMMMV rollover events, and the results from both methods show that simulation and test data agreed fairly well. Computational time reduced by the ROMM was about 53% of that of the FSM. ROMM approach not only saves significant computational time but also increases robustness of the simulation. Citation: V. Babu, J. Kang, S. Kankanalapalli, J. Sheng, M. Vunnam, S. K. Karwaczynski, C. Jessup, M. Duncan, K. Paulson, “REDUCED ORDER MODELLING METHOD (ROMM) FOR GROUND VEHICLE ROLLOVER PROTECTION M&S”, In Proceedings of the Ground Vehicle Systems Engineering and Technology Symposium (GVSETS), NDIA, Novi, MI, Aug. 10-12, 2021.
Babu, V., Kang, J., Kankanalapalli, S., Sheng, J., Vunnam, M., Karwaczynski, S. K., Jessup, C., Duncan, M., Paulson, K.
Full-scale Crash Test of the AW609 WingF-0080-2024-12225/7/2024
The AW609 tiltrotor features a unique high-mounted wing with rotatable nacelles positioned at the wing tips, it is capable of operating both in airplane and vertical flight mode. To achieve suited protection of the occupants during emergency landing, the wing - which is particularly stiff in order to sustain the heavy weights at the tips, where rotors, engines and transmissions are positioned - implements a controlled failure mechanism at root, so that during emergency landings it breaks and unloads the fuselage of the weight of wingbox and nacelles, thus avoiding catastrophic collapse. As the effectiveness of such mechanism was never demonstrated under impact conditions, certification agencies requested an empirical validation through experimental testing. The test was carried out July 2022 at Polytechnic of Milan, Italy; the present work details the Test activity, from its preliminary phases to the Test Day, to the analyses of its outcomes.
Colamartino, Ivan, Cavalera, Davide, Turconi, Fabrizio, Anghileri, Marco, Di Renzo, Andrea
testing tasks 2 jms test citSAE-PP-004629/28/2021
2 go
SintzADMIN, Jeneane, SintzUSER, Jeneane
Products of Tomorrow: February 2020TBMG-359682/1/2020
This column presents technologies that have applications in commercial areas, possibly creating the products of tomorrow. To learn more about each technology, see the contact information provided for that innovation.
The Effects of Front-Mounted Accessories on Air Bag Sensors and CrashworthinessJ2431_201910 (Current)10/9/2019
Almost all light trucks now are being manufactured with at least a driver side air bag and all will have dual air bags by 1998. The driving forces behind this feature are occupant safety, federal regulations, and competition in the industry. Along with the booming popularity of pickups and SUVs, they are commonly accessorized with a wide variety of products. Many accessories for four-wheel drives in particular are mounted on the front of the vehicle. These products include grille/brush guards, winches, snow plows, replacement bumpers, bicycle carriers, etc. Concerns have arisen over the compatibility of these accessories with the vehicle’s air bag system. The vehicle manufacturers are concerned because of their huge investment in design and crash test verification of the complete vehicle system and keen awareness of the federal regulations. The crushability of the front bumper and supporting structure are key elements in the system, so alterations to that area become logical concerns. The accessory manufacturers, dealers, and installers are concerned because the very core of their business could be at risk. The unknowns can range from fear of setting off an airbag while working on the vehicle to liability issues in an injury accident situation. In some cases, the installation of the product is contrary to recommendations from the vehicle manufacturer and may void the warranty. The ultimate customers (end users) are in a unique situation and are not being well served in some situations. Their dilemma stems from the conflict between what a manufacturer is willing to certify for sale and what the customer needs and expectations are. Their needs in vehicle equipment can vary widely from making a living to recreational lifestyle issues to simplify the desire to individualize. The precedent for front-mounted accessories is well established. The customers for both the vehicle and the equipment are there, so finding ways for them to coexist safely is beneficial to all.
Motor Vehicle Council
Evaluation of Impact Energy Attenuators and Composite Material Designs of a UAM VTOL Concept VehicleF-0075-2019-145545/13/2019
The development of Vertical Take-off and Landing (VTOL) vehicles for the Urban Air Mobility (UAM) markets presents a need for light weight vehicle structures with effective occupant protection capabilities. The National Aeronautics and Space Administration (NASA) has been working to fill that need, recently developing a cadre of concept vehicles to help characterize UAM design feasibility. This paper describes a study, using these concept vehicles, to evaluate the use of advanced composite structure and energy attenuating designs in the UAM vehicle design space. A finite element model (FEM) of a single passenger quadrotor concept vehicle was developed in LS- Dyna® and simulated under nominal and off-nominal vertical impact conditions. A variety of energy attenuating design mechanisms were implemented within this model to quantify their effectiveness in improving occupant safety. The use of carbon composites in both the energy attenuation mechanisms and vehicle structure was evaluated. The results of this study found significant reduction in occupant injury risk with the implementation of energy absorbing composite crush tubes and landing gear within the vehicle design. Additionally the use of a carbon fiber as a structural material was found to provide significant weight reduction while maintaining similar occupant loads to that predicted with an aluminum structure. This work provides a preliminary evaluation of design mechanisms and materials that may be used to optimize occupant protection capabilities within the UAM market.
Putnam, Jacob, Littell, Justin
The Navigator19AVEP05_035/1/2019
Lessons from the 737 Max-8 Debacle It's always a tragedy when people die as a result of a machine malfunctioning. It's even more tragic if we fail to learn from that failure to make future machines safer. In recent months, two practically new Boeing 737 Max-8 jetliners have crashed claiming more than 300 lives. While we don't yet have the final results of the investigations, early indications point to new automation systems, the way they were validated, and the way operators were trained. As we rush headlong into the era of automated driving, this seems like a remarkably teachable moment.
Abuelsamid, Sam
Analysis of Rear Seat Sled Tests with the 5th Female Hybrid III: Incorrect Conclusions in Bidez et al. SAE 2005-01-17082019-01-06184/2/2019
Objective: Sled test video and data were independently analyzed to assess the validity of statements and conclusions reported in Bidez et al. SAE paper 2005-01-1708 [7]. Method: An independent review and analysis of the test data and video was conducted for 9 sled tests at 35 km/h (21.5 mph). The 5th female Hybrid III was lap-shoulder belted in the 2nd or 3rd row seat of a SUV buck. For one series, the angle was varied from 0, 15, 30, 45 and 60 deg PDOF. The second series involved shoulder belt pretensioning and other belt modifications. Results: Bidez et al. [7] claimed “The lap belts moved up and over the pelvis of the small female dummy for all impact angles tested.” We found that there was no submarining in any of the tests with the production lap-shoulder belts. Bidez et al. [7] claimed “H3-5F dummies began to roll out of their shoulder belt at… 30 degrees. Complete loss of torso support was seen at 45 degrees without significant kinetic energy dissipation.” We found that the shoulder belt remained in place and restrained the upper torso in the 0, 15 and 30 deg sled tests. At 45 and 60 deg, significant restraint was provided before the belt slipped off the shoulder. It remained in contact with the arm and chest providing restraint. Bidez et al. [7] claimed “The results indicated kinematic movement of the dummies, which were predictive of injury in all sled runs.” We found that the kinematic control was good and the biomechanical responses were well below IARVs for the 5th female Hybrid III. Bidez et al. [7] claimed “a retractor pretensioner (7 ms fire time) eliminated both submarining and torso rollout in the H3-5F in the conditions tested.” We found that the pretensioner firing pulled the lap belt up onto the abdomen inducing submarining and causing abdominal loading in two out of four tests. Conclusion: The independent review of the videos and data shows that Bidez et al. [7] misstated the results, misrepresented the findings and reached incorrect conclusions on the testing.
Viano, David, Parenteau, Chantal
Evaluation of Occupant Loading in Low- to Moderate-Speed Frontal and Rear-End Motor Vehicle Collisions2019-01-12204/2/2019
Low- to moderate-speed motor vehicle collisions are common roadway occurrences that are generally associated with low rates of reported injury. While such complaints are generally infrequent, claims of injuries resulting from low- to moderate-speed motor vehicle collisions persist. A limited body of literature using quantitative techniques and full-scale crash tests is available to assess the injury potential associated with such collisions. Prior studies have analyzed occupant kinematics and kinetics as well as human injury risk in low- to moderate-speed collisions with older vehicle vintages but do not assess the effects of updated vehicle interior designs and occupant protection devices reflective of efforts to optimize occupant kinematics and reduce occupant loading and injury risk in more modern vehicles. This study was conducted to evaluate the injury potential for occupants of vehicles with modern design elements involved in low- to moderate-speed inline motor vehicle collisions. We expected to find that occupants in modern vehicles would demonstrate low potential for injury in such collisions. Four full-scale inline (collinear) crash tests were conducted to assess occupant loading during frontal and rear-end impacts. The vehicles used in each test were instrumented late-model, mid-sized sedans of the same make and model occupied by restrained and instrumented Hybrid III 50th-percentile male anthropomorphic test devices (ATDs). The tests involved aligned front-to-rear bumper collisions at closing speeds ranging from 7.4 kph to 33.6 kph (4.6 mph to 20.9 mph). Kinetic data collected from the instrumented ATDs were evaluated to assess the biomechanical loading environment throughout the crash pulse in both the striking (bullet) and struck (target) vehicles. Evaluation of the occupant responses established that the loads and moments generated during these low- to moderate-speed collisions were far less than accepted injury assessment reference values (IARVs). Furthermore, the recorded spinal loads demonstrated characteristics of inertial loading with similar timescales as common daily activities and, in many cases, were of magnitudes less than or comparable to loads generated by volunteers performing volitional and non-injurious activities.
Toney-Bolger, Megan, Campbell, Ian, Miller, Bruce, Davis, Mathieu, Fisher, Jacob
Effects of Innovation in Automated Vehicles on Occupant Compartment Designs, Evaluation, and Safety: A Review of Public Marketing, Literature, and Standards2019-01-12234/2/2019
In recent years, the discussion around the advent of highly automated vehicles has shifted from “if” to “when.” Commercially available vehicles already incorporate automated vehicle (AV) technologies of varying capability, and the eventual transition to fully automated systems, at least within certain predefined Operational Design Domains, is largely considered inevitable. While the full ramifications of this shift and the eventual depreciation of human driver control are still under intense debate, there is broad agreement on one issue -the advent of driverless systems will remove several constraints on the design of vehicle interior spaces, creating the opportunity for innovation. Even at this early stage, ambitious design concepts of purpose specific vehicles - mobile gyms, offices, bedrooms - have been proposed. More grounded designs, such as rotating passenger seats, have also been put forward. However, there are two other points on which general agreement exists - future AVs will still carry human passengers, and crashes will still occur, however infrequent or less severe. The uncertainty of the future occupant compartment design and crash population will introduce a new set of challenges for occupant protection and predicting injury risk in the future vehicle fleet. This paper explores various proposed design changes to the space of the interior of future automated vehicles, the effects of potential changes on occupant safety during collisions, and the capabilities of the existing testing approaches, design tools, and databases to address questions arising from these developments.
Filatov, Anton, Scanlon, John M., Bruno, Alexander, Danthurthi, Sri Sai Kameshwari, Fisher, Jacob
The Effects of Inboard Shoulder Belt and Lap Belt Loadings on Chest Deflection2018-22-000211/12/2018
Chest injuries occur frequently in frontal collisions. During impact, tension in the lap belt is transferred to the inboard shoulder belt, which compresses the lower ribs of the occupant. In this research, inboard shoulder belt and lap belt geometries and forces were investigated to reduce chest deflection. First, the inboard shoulder belt geometry was changed by the lap/shoulder belt (L/S) junction for the rear seat occupant in sled tests using Hybrid III finite element simulation, sled tests and THOR simulation. As the L/S junction was closer to the ASIS (anterior superior iliac spine), chest deflection of the Hybrid III was smaller. The L/S junction around the ilium has the potential to reduce chest deflection without significant increase of head excursion. For THOR, although the chest deflection reduction effect due to closer L/S junction to the ASIS was observed, chest deflection was still substantially large since the lap belt overrode the ASIS. Second, measures to hook the ASIS of the THOR by the lap belt were examined. Sled tests at 30 and 50 km/h were conducted with THOR in the rear seat, and it was demonstrated that the outboard lap belt and buckle pretensioners improved the lap belt and ASIS interaction, and were also useful in reducing the deflection at the inboard-side of the lower chest. Finally, the lap belt overlap with the ASIS was compared among 10 volunteers, Hybrid III, and THOR. Some volunteers had the ASIS located at the torso-thigh junction, and the lap belt did not overlap the ASIS sufficiently. However, although the ASIS location of THOR is also at the torso-thigh junction, the lap belt overlapped the ASIS because of the abdomen’s and femur’s shape. In the future, it will be necessary to consider that the outboard lap belt and buckle pretensioners are also effective for the ASIS restraint of all human car occupants.
Mizuno, Koji, Yoshida, Ryoichi, Nakajima, Yutaka, Tanaka, Yoshihiko, Ishigaki, Ryota, Hosokawa, Naruyuki, Hitosugi, Masahito
Performance Standard for Passenger Smoke and Toxic Fumes Respiratory Protective EquipmentAS8048 (Historical)10/18/2018
This SAE Aerospace Standard (AS) defines the performance requirements for equipment to be used by untrained cabin occupants for protection from toxic and irritant atmospheres while on board and during evacuation of an aircraft.
A-10 Aircraft Oxygen Equipment Committee
Autonomous vehicles present passive-safety challenges18AUTP10_0810/1/2018
Reclined and rotated seating positions are commonly depicted for autonomously driven vehicles. But for the Autoliv engineers tasked with developing occupant safety for tomorrow's self-driving vehicles, those previously improbable seating positions dictate innovative new passive safety protections. “Passive safety for autonomous vehicles is a pretty complicated problem to solve, which is why we're starting out with the simplest scenario: a frontal crash with a front occupant in a partial-recline position,” E. Scott Dershem, Autoliv's Vice President of Product Development, said in an interview with Automotive Engineering at the safety supplier's Auburn Hills, Michigan technical center.
Buchholz, Kami
Development of Component Level Transfer Equations of Simplified Human and ATD Occupant Models09-06-01-00056/5/2018
Safety systems have historically been evaluated with anthropomorphic test devices for research, development, or regulatory concerns. Human body models are another avenue for use in the investigation of occupant safety. In this study, transfer equations are developed to quantify the response of a human model (Global Human Body Models Consortium average male simplified model) and dummy model (Hybrid-III) in equivalent environments. Environments were selected based on certification test setups used for the Hybrid III ATD as well as a basic frontal sled environment. The tests include a head drop, neck flexion/extension, and chest and knee impacts. Furthermore, models were positioned within a simplified occupant interior for sled tests. In all, 30 matched pair simulations were run, 60 in total. Peak metrics between human and anthropomorphic test device models showed strong linear correlation in component testing however, as the complexity of the simulations increased, agreement tended to decrease. Kinematic data are also presented and they trend similarly between human and anthropomorphic test device models however they exhibit different timing and peaks. Within the range tested, the developed transfer equations can be used to estimate performance of one model if data from the other is available. Furthermore, the evaluation of risk for these equivalent impacts is provided for HIC-15, max chest deflections and femur forces aggregated across all tests. Over the range tested, equivalent impacts result in roughly equivalent risk levels with the exception of the femur, which resulted in higher forces in the Hybrid III and thus predicted higher risk.
Guleyupoglu, Berkan, Koya, Bharath, Gayzik, Francis Scott
Using Shoulder Bolster and Knee Bolster to Achieve Protection Effect Comparable to Seatbelt and Airbag2018-01-11704/3/2018
Seatbelt and airbags provide effective occupant restraint, but are also potential to induce intrusive deformation and submarining injuries in motor vehicle crashes. To address these issues, this study puts forward a new restraint concept that applies restraint loads on shoulders and knees/femurs, i.e., the sturdiest regions of human body, via a combined use of shoulder bolster and knee bolster based on biomechanical computational analysis. The load characteristics of the two bolsters were optimized to obtain protection effectiveness superior to conventional use of seatbelt and airbag. Occupant kinematics and kinetics were taken into account, including the excursions of head, shoulders and knees, the accelerations of head and chest, and the compressions of thorax on several locations on the ribcage. The injury risk of rib fractures was monitored based on the strain levels of ribcage. Results show that applying adaptive restraint loads on the sturdy regions of human body using shoulder bolster and knee bolster can ensure reasonable kinematical motion and acceptable injury levels of occupant, and can also avoid intrusive deformations in thorax and abdomen as well as airbag hazards. The protection effect of shoulder bolster and knee bolster is comparable or superior to that of using seatbelt and airbag. To achieve a balance of comfort and safety in autonomous driving environment, the system will be activated only when collision is sensed unavoidable.
Huang, Yuan, Zhou, Qing, Ji, Peijun, Nie, Bingbing
Optimizing Occupant Restraint Systems for Tactical Vehicles in Frontal Crashes2018-01-06214/3/2018
The objective of this study was to optimize the occupant restraint systems for a light tactical vehicle in frontal crashes. A combination of sled testing and computational modeling were performed to find the optimal seatbelt and airbag designs for protecting occupants represented by three size of ATDs and two military gear configurations. This study started with 20 sled frontal crash tests to setup the baseline performance of existing seatbelts, which have been presented previously; followed by parametric computational simulations to find the best combinations of seatbelt and airbag designs for different sizes of ATDs and military gear configurations involving both driver and passengers. Then 12 sled tests were conducted with the simulation-recommended restraint designs. The test results were further used to validate the models. Another series of computational simulations and 4 sled tests were performed to fine-tune the optimal restraint design solutions. The sled tests with the optimized seatbelt and airbag designs provided significant improvement of occupant protection from the baseline tests in terms of the head, neck, chest, and lower extremity injury measures. Using a baseline seatbelt without an airbag, the ATD tended to contact the steering wheel or the instrument panel, or sustained a significant head whipping motion inducing large head and neck injury measures. By adding the airbag and reducing the load limit in the seatbelt, the injury measures were improved significantly. This study demonstrated the benefit of adding a properly designed airbag and advanced seatbelt to improve the occupant protection in frontal crashes under an environment representing a light tactical vehicle.
Hu, Jingwen, Ritchie Orton, Nichole, Chen, Cong, Reed, Matthew, Rupp, Jonathan, Gruber, Rebekah, Clark, David, Scherer, Risa
A Fast Running Loading Methodology for Ground Vehicle Underbody Blast Events2018-01-06204/3/2018
A full-system, end-to-end blast modeling and simulation of vehicle underbody buried blast events typically includes detailed modeling of soil, high explosive (HE) charge and air. The complex computations involved in these simulations take days to just capture the initial 50-millisecond blast-off phase, and in some cases, even weeks. The single most intricate step in the buried blast event simulation is in the modeling of the explosive loading on the underbody structure from the blast products; it is also one of the most computationally expensive steps of the simulation. Therefore, there is significant interest in the modeling and simulation community to develop various methodologies for fast running tools to run full simulation events in quicker turnarounds of time. This paper discusses investigation of a fast running blast loading methodology wherein the effects of the soil can be adequately captured without having to employ a highly detailed and computationally intensive soil/explosive model, and the interactions thereof (with each other and with the vehicle), in the simulation. The paper will also present a basis of such methodology utilizing the free air-blast loading data that is readily available and implemented in LS-DYNA, the technical approach for matching the buried blast loading patterns using free-air blast datasets and selection of test cases for evaluation and validation. Test cases include simple flat plate with high deformation and a generic vehicle representative of a military ground vehicle. The results from the development and validation of the methodology are presented along with future technical development strategies.
Ramalingam, Jaisankar, Thyagarajan, Ravi
Dynamic Performance Assessment of Side Facing Troop Seats During ImpactF-0073-2017-120395/9/2017
ABSTRACT The Air Force Research Laboratory Aircrew Biodynamics and Protection Group of the Applied Neuroscience Branch (711HPW/RHCPT) conducted a dynamic impact comparative test program of currently-fielded side facing troop seats to evaluate how effectively the seats protect occupants ranging from the 5th percentile female to the 98th percentile male during crash events. The test program consisted of impact testing stock H-60A/L, CV-22, and CH-53E seats and quantifying the safety effectiveness of each seat using recommended injury criteria from the Full Spectrum Crashworthiness (FSC) report and other historical criteria. The program demonstrates a methodology to quickly and inexpensively compare occupant protection across different designs and platforms. The program also identifies serious structural and functional deficiencies of several operational seats that correlate with rotorcraft mishap injury and mortality data.
Wright, Nathan, Burneka, Chris
Stable and Accurate LS-DYNA Simulations with Foam Material Models: Optimization of Finite Element Model Parameters2017-01-13383/28/2017
Cellular foams have found a predominant application in automotive industry for efficient energy absorption so as to meet stringent and continuously improving vehicle crashworthiness and occupant protection criteria. The recent inclusion of pedestrian protection regulations mandate the use of foams of different densities for impact energy absorption at identified impact locations; this has paved the way for significant advancements in foam molding techniques such as dual density and tri-density molding. With increased emphasis on light-weighting, solutions involving the use of polymeric or metallic foams as fillers in hollow structures - foam encapsulated metal structures - are being explored. Another major automotive application of foams is in the seat comfort area, which again involves foams of intricate shapes and sizes. In addition, a few recently developed foams are anisotropic, adding on to the existing complexities. Complexities associated with controlled/ uncontrolled spatial variation in density and the geometry of molded parts and use of foams in sandwich composites offer several challenges for the CAE community in modeling the foam components. As a first step to capture these complexities, optimal settings of available LS-DYNA modeling features have to be determined to enable effective Finite Element Analysis (FEA) of foam components. This paper aims to investigate the various underlying parameters such as element formulations and size, contact stiffness and hourglass control, governing stability and accuracy of foam material models and to identify the optimal settings of these parameters. The optimal settings for the identified parameters are elucidated in the context of the rate dependent foam model in LS-DYNA (Fu-Chang Foam).
Ramaswamy, Karthik, Patham, Bhaskar, Savic, Vesna, Tripathy, Biswajit
Full Instrumentation of Side Impact Pole and In-Depth Analysis of Vehicle Structural Behavior2016-36-012810/25/2016
In order to obtain more information from the side impact tests, a pole was fully instrumented with triaxle load cells. Also, a sled modification was carried out providing a sub-frame view of the vehicle during the entire test and making possible to compare the structure and element deformations with the obtained data. An in-depth analysis of vehicle structural behavior focused on the forces received by the vehicle during the pole side impact test was made. A crash test was set to validate the acquisition system of the instrumented pole. The obtained data like the forces and the deformations were analyzed in depth and used for a structural study of the vehicle. The data acquired by the acquisition system was used to obtain a force diagram from the pole and a comparison was made with the vehicle absorption mechanisms and structural elements involved. Moreover, the force data was compared with the sub-frame view and with the structural element’s deformation. With the results, it was possible to have a complete view of the interaction between the vehicle and the pole and how it affects the vehicle structure during the entire test. In order to obtain those results, frame to frame with the high-velocity videos form different positions were obtained and the sub-frame view of the car during the test was used This kind of study are carried out for the clients, due to confidentiality reasons no pictures will be sown in this paper. The fully instrumentation of the pole and the sub-frame vision will make it possible to know the most critical parts of the vehicle structure in the side impact pole test and their performance. Also, it will help to define the structural parts that need to be improved in the vehicle and the different aspects that need to be taken into account in order to guarantee the safety of the occupants.
Sanchez, Jacob, Malivern, Melcior, Parera, Núria, Fornells, Alba
Evaluation of Aerospace Seat Belt Webbing Material Under Dynamic Test ConditionsF-0072-2016-114135/17/2016
There is no requirement for full-scale testing of either civil or military rotorcraft to certify a design as safe or crashworthy. The Federal Aviation Administration has a number of standards and regulations that are designed to protect occupants in the event of a crash. These standards focus primarily on frontal and vertical impact protection of the occupant seating system and those items in the cabin interior that surround the occupant. With the adoption of Title 14 Code of Federal Regulations (CFR) 29.562, as well as the corresponding portions of 14 CFR 23.562, 25.562, and 27.562, a seating system is comprised of the seat, all attachment hardware, and the restraint system. In this methodology, the attachments and the restraint are approved for use at the same time as the seat itself. One restraint cannot be readily swapped out for another restraint and any repairs of the restraint itself must return it back to its original specifications. Inherent material properties of common webbing materials may affect the dynamic response of the seat system. To determine how differences in elongation properties affect seat dynamic response, a test program using a rigid seat setup in different configurations with different webbing materials was conducted by the FAA. The selected configurations represented seats commonly in use. Both new and newly repaired belts were acquired for this study. As part of this test program, a second phase was conducted to investigate the effects of belt stiffness. Original belt webbing material and several replacement webbing material candidates were statically tested to determine their elongation properties. These belts were then subjected to the same test setup as in phase 1; however, unlike phase 1, only one seating configuration was tested. All these different belts were then subjected to dynamic impact tests using a rigid seat and the sled test pulse from Title 14 Code of Federal Regulations 25.562. No structural failures occurred in any of the tests. A trend was noted that higher belt stiffness resulted in less occupant excursion and higher belt loads. It was also noted that static belt stiffness can be used to characterize relative belt performance in dynamic tests. These data can be used to develop general guidelines on allowable webbing changes for previously approved seat belts.
Pellettiere, Joseph, Huculak, Robert, DeWeese, Richard
A Semi-Automated Approach to Real World Motor Vehicle Crash Reconstruction Using a Generic Simplified Vehicle Buck Model2016-01-14884/5/2016
Computational finite element (FE) modeling of real world motor vehicle crashes (MVCs) is valuable for analyzing crash-induced injury patterns and mechanisms. Due to unavailability of detailed modern FE vehicle models, a simplified vehicle model (SVM) based on laser scans of fourteen modern vehicle interiors was used. A crash reconstruction algorithm was developed to semi-automatically tune the properties of the SVM to a particular vehicle make and model, and subsequently reconstruct a real world MVC using the tuned SVM. The required algorithm inputs are anthropomorphic test device position data, deceleration crash pulses from a specific New Car Assessment Program (NCAP) crash test, and vehicle interior property ranges. A series of automated geometric transformations and five LSDyna positioning simulations were performed to match the FE Hybrid III’s (HIII) position within the SVM to reported data. Once positioned, a baseline simulation using the crash test pulse was created. A Latin hypercube sample space (9 variables) of 120 simulations was created to vary occupant safety and restraint properties. Sprague and Geers magnitude and phase error factors were used to identify an optimal set of restraint parameters to reconstruct the HIII kinematic and kinetic responses. Using the tuned SVM, event data recorder pulses from real world crashes, and the Total HUman Model for Safety, LS-Dyna simulations were used to reconstruct the occupant-vehicle interactions. In a sample case, stress, strain, and dynamic loads were evaluated to predict rib, sternum, and vertebral injuries sustained by the occupant in the crash.
Jones, Derek, Gaewsky, James, Weaver, Ashley, Stitzel, Joel
Load-Limiters Effect on Occupant Restraint System Performance2016-01-15054/5/2016
This paper investigates the role that load-limiters play with respect to the performance of occupant protection systems, with focus on performance in frontal crashes. Modern occupant protection systems consist of not just the seat belt, but also airbags, interior vehicle surfaces and vehicle structure. Modern seat belts very often incorporate load-limiters as well as pretensioners. Published research has established that load-limiters and pretensioners increase the effectiveness of occupant protection systems. Some have argued that load-limiters with higher deployment thresholds are always better than load-limiters with lower deployment thresholds. Through testing, modeling and analysis, we have investigated this hypothesis, and in this paper we present test and modeling data as well as a discussion to this data and engineering mechanics to explain why this hypothesis is incorrect. Research presented in this paper shows that because load-limiters are just one component of a multi-component occupant protection system, the performance of the overall occupant protection system cannot be predicted from the load-limiter performance or specifications alone. The overall occupant protection system is designed such that the load-limiter works in conjunction with the webbing stiffness, airbag, vehicle interior surfaces and vehicle structure to provide effective occupant protection. This paper shows that effective occupant protection has been achieved using different combinations of these parameters. The appropriate method of evaluating the effectiveness of an occupant protection system is to evaluate the overall performance of that occupant protection system in sled and crash tests and/or calibrated modeling. Tests of load-limiters alone or reliance on the load-limiter specification alone is not a good indicator of the overall effectiveness of an occupant protection system. Tests were conducted to establish the level at which certain retractor load-limiters deployed webbing. This data was cross-referenced with publically available test data, and shoulder belt loads, chest deflection and chest compression, among other injury metrics. Computer modeling was conducted to assess the effect of varying initial load-limiter deployment loads.
Van Arsdell, William W., Weber, Paul, Stankewich, Charles, Larson, Brian, Hoover, Ryan, Watson, Richard
Preliminary study of uniform restraint concept for protection of rear-seat occupant under mid and high crash severities2016-01-15284/5/2016
As the restraint technologies for front-seat occupant protection advance, such as seatbelt pre-tensioner, seatbelt load limiter and airbag, relative effectiveness of rear-seat occupant protection decreases, especially for the elderly. Some occupant protection systems for front-seat have been proved to be effective for rear-seat occupant protection as well, but they also have some drawbacks. Seatbelt could generate unwanted local penetrations to the chest and abdomen. And for rear-seat occupants, it might be difficult to install airbag and set deployment time. For crash protection, it is desirable that the restraint loads are spread to the sturdy parts of human body such as head, shoulders, rib cage, pelvis and femurs, as uniformly as possible. This paper explores a uniform restraint concept aiming at providing protection in wide range of impact severity for rear-seat occupants. In this study, we use THUMS 50th percentile occupant model to simulate response under sled test frontal impact loading. The occupant is restrained by uniform restraint forces respectively acting on head, upper torso and shoulders, and lower extremities in a spread way, through three “plates” respectively positioned against head, upper torso and shoulders, and knees. The force levels are control parameters, which are manually optimized for adapting to crash severity, for maintaining reasonable occupant posture and body kinematics, and resulting in acceptable injuries. Rib fractures, chest deflection, chest acceleration and head acceleration are monitored in simulations. The results show that the restraint forces distributed on the sturdy parts of human body in such a spread way could be more efficient than seatbelt, and can provide rear-seat occupants protection in a wider range of impact velocity with adaptable level of restraint force.
Ji, Peijun, Zhou, Qing
Optimization of Seatbelt Anchorage Mount Locations for Occupant Injury Reduction in Frontal Crash2016-28-02512/1/2016
In the event of a frontal car crash, occupant sitting in a car meets various types of injuries like Head injury, Chest compression, Neck injury etc. These injuries may lead to the death of an occupant if exceeded beyond biomechanical limits. Seat belt is a primary restraint system, which when worn controls the motion of occupant sitting inside the car during the event of a car crash. An Anchorage location of three point seat belt system has significant effect on occupant injuries during the crash event. By changing the mount locations of a seat belt anchor points i.e. D-ring, Anchor & Buckle, performance of seatbelt system can be enhanced further thereby reducing occupant injuries to certain extent. As per regulation AIS015, locations of safety belt anchorage points should be within prescribed zone. This paper explains effect of changing mounting location of each anchorage points on occupant injuries & also explains how to find optimized seat belt anchorage mount locations within prescribed zone mentioned as per regulations keeping various occupant injuries to minimal value.
Patil, Kantilal, Reddy, Siva, Zafar, Nadeem
Comparison of ATD to PMHS Response in the Under-Body Blast Environment2015-22-001711/9/2015
A blast buck (Accelerative Loading Fixture, or ALF) was developed for studying underbody blast events in a laboratory-like setting. It was designed to provide a high-magnitude, high-rate, vertical loading environment for cadaver and dummy testing. It consists of a platform with a reinforcing cage that supports adjustable-height rigid seats for two crew positions. The platform has a heavy frame with a deformable floor insert. Fourteen tests were conducted using fourteen PMHS (post mortem human surrogates) and the Hybrid III ATD (Anthropomorphic Test Device). Tests were conducted at two charge levels: enhanced and mild. The surrogates were tested with and without PPE (Personal Protective Equipment), and in two different postures: nominal (knee angle of 90°) and obtuse (knee angle of 120°). The ALF reproduces damage in the PMHS commensurate with injuries experienced in theater, with the most common damage being to the pelvis and ankle. Load is transmitted through the surrogates in a caudal-to-cranial sequential fashion. Damage to the PMHS lower extremities begins within 2 ms after the initiation of foot/floor motion. The Hybrid III cannot assume the posture of the PMHS in rigid seats and exhibits a stiffer overall response compared to the PMHS. The ATD does not mimic the kinematic response of the PMHS lower extremities. Further, the Hybrid III does not have the capability to predict the potential for injury in the high-rate, vertical loading environment. A new ATD dedicated to under-body blast is needed to assist in the effort to mitigate injuries sustained by the mounted soldier.
Danelson, Kerry A., Kemper, Andrew R., Mason, Matthew J., Tegtmeyer, Michael, Swiatkowski, Sean A., Bolte IV, John H., Hardy, Warren N.
Finite Element Analysis and Validation of Bus Seat Structure as per AIS023: Safety Features Evaluation of Bus Seat using Hybrid III Dummy2015-01-28699/29/2015
Buses are always one of the main and favorite sources of public transit. Thousands of people die or injure every year in bus accidents. Bus seat can also cause severe injury to the occupants in case of frontal impact. Seat structure of the bus should absorb sufficient energy to minimize the passenger injury. Most of the occupants seated in the second row or further back were injured by hitting the seat back in the row in front of them. In India, AIS023 (Automotive Industry Standards) is one of the several mandatory standards from CMVR (Central Motor Vehicles Rules) to ensure the seat strength and occupant safety during accidents. This standard specifies minimum and maximum deformations range for the seat back to minimize the passenger injury with adequate seat strength. Present study includes the Finite Element Analysis (FEA) and correlation of bus seat as per AIS023 test setup with LS-Dyna explicit tool. Reasonable correlation was found between test and simulation results. This correlated Finite Element (FE) model then used to calculate the injury levels using 50th percentile Hybrid III midsize male dummy. Final results ensure the safety capability of the seat structure in front impact. This procedure was used to enhance safety in passenger bus seats.
Sharma, Sumit, Sharma, Sandeep, Gupta, Umashanker, Joshi, Ravi, Pawar, Shailesh
Crash Dynamic Model for Rotorcraft Adaptive Seat Energy Absorber EvaluationF-0071-2015-101435/5/2015
ABSTRACT This research study focuses on the finite-element based nonlinear dynamic model development and analysis for virtual evaluation of adaptive seat dampers for enhanced occupant protection during vertical crash landings of a helicopter. The current state-of-the-art helicopter crew seat has passive safety mechanisms that are highly limited in their capability to optimally adapt to each type of crash scenario due to variations in both occupant weight and crash severity level. While passive crash energy absorbers work well for a single design condition (50th percentile male occupant and fixed crash severity level), they do not offer adequate protection across a broad spectrum of crash conditions by minimizing the load transmitted to the occupant. This study reports the development of a finite-element based seat-occupant system level model using LS-DYNA for rotorcraft crash injury simulation. This finite element simulation model of a seated occupant with five-point belt and stroking seat is used to study occupant kinematics and spinal injury assessments to support crash sled evaluations of seat energy absorbers. The injury criteria and tolerance levels for the biomechanical effects are discussed for each of the adult-sized occupants with respect to thoracic lumbar loads. The desired objective of this analytical model development is to develop a tool to study the performance effectiveness of adaptive seat energy absorbers for enhancing rotorcraft occupant crash protection.
Murugan, Muthuvel, Tabiei, Ala, Hiemenz, Gregory
The Application of Hybrid III 5 th Percentile Dummy FE Model for Rear Row Occupant Simulation in Frontal Crash Test2015-01-14584/14/2015
A Finite Element (FE) model for analysis of the rear row occupant injury assessment parameters in a frontal crash test was developed by using the LSTC Hybrid III 5th percentile FE dummy model. Three cases were studied using three different rear seatbelt retractor configurations, which were as follows: an ordinary retractor without load limiter or pretensioner (Case 1), a retractor with load limiter only (Case 2), and a retractor with load limiter and pretensioner (Case 3). The simulation results of each of these three cases were compared respectively to the results obtained from two frontal 50-kph full rigid barrier impact tests and one sled test. It turned out that the dummy kinematics and injury assessment parameters of the head, neck, chest, pelvis and femurs were all similar between test and simulation in the three cases. Thus, FE simulation models can be used to predict dummy injury assessment parameters. The chest and pelvis accelerations and chest deflection reduced, while the head acceleration and neck forces increased in the case of “retractor with load limiter” (Case 2), compared to the case of “ordinary retractor” (Case 1). The most effective way to reduce all the injury assessment parameters was to use a “load limiting retractor together with a pretensioner” (Case 3).
Hu, Jia
Effects of Crash Pulse, Impact Angle, Occupant Size, Front Seat Location, and Restraint System on Rear Seat Occupant Protection2015-01-14534/14/2015
In this study, two sled series were conducted with a sled buck representing a compact vehicle. The first series of tests focused on the effects of crash pulse, impact angle, occupant size, and front seat location on rear seat occupant restraint with a generic rear-seat belt system without pre-tensioner or load limiter. The second series of tests focused on investigating the benefit of using advanced features for rear-seat occupant restraint in the most severe crash condition in the first sled series. The first series of tests include 16 test conditions with two impact angles (0° and 15°), two sled pulse (soft and severe), and four ATD sizes (HIII 6YO, HIII 5th female, HIII 95th male, and THOR-NT) with two ATDs in each test. The driver seat was located at the mid position, while the front passenger seat was positioned such that a constant distance between the ATD knee and the front seat is achieved. In all the tests, a generic rear-seat belt system without pre-tensioner, load limiter or dynamic locking tongue (DLT) was used. Test results from the first sled series showed that crash pulse and occupant size are the two dominating factors affecting the ATD kinematics and injury measurements, while impact angle and front-seat location are not statistically significant. Although no head-to-front-seat contact occurred in any of the tests, in general, the severe crash pulse would result in chest deflections over the injury criteria for adult ATDs with higher ATD excursions than for the soft crash pulse. These results are consistent to those from the field data in that chest injuries are the most common injuries in rear-seat adult occupants. The HIII 6YO ATD sustained submarining kinematics in all the tests due to the slouching pre-crash posture. In an attempt to help further reduce the chest loading while managing the head excursion, 3-point belts with pre-tensioner and load limiter, 4-point belts, DLT, inflatable belts, Bag in Roof (BiR) concept, and Self Conforming Rear-seat Air Bag (SCaRAB) concept were investigated in the second series of sled tests, in which only the most severe testing condition (0° and severe pulse) in the first sled series was used. Reductions in occupant loading were shown with these advanced restraint systems, especially the airbag features, to help reduce head, neck, and chest injury measures for rear-seat occupants. This study demonstrated the importance of considering the effects of occupant size and crash pulse on rear-seat occupant protection. Advanced restraint systems including features such as a pre-tensioner, a load limiter, and an airbag, may have the potential to help provide additional protection for rear-seat occupants with diverse occupant sizes.
Hu, Jingwen, Fischer, Kurt, Lange, Paul, Adler, Angelo
Simulation Fidelity Improvement of H350 Lower Tibia Indices2015-01-05784/14/2015
Finite element dummy models have been more and more widely applied in virtual development of occupant protection systems across the automotive industry due to their predictive capabilities. H350 dyna dummy model [1] is a finite element representation of the Hybrid III male dummy [2], which is designed to represent the average of the United States adult male population. Lower extremity injuries continue to occur in front crash accidents despite increasing improvement of vehicle crashworthiness and occupant restraint system. It is therefore desirable to predict lower tibia injury numbers in front occupant simulations. Though lower tibia loading/index predictions are not studied as much as the FMVSS 208 regulated injury numbers, the tibia indices are injury criteria that need to be assessed during IIHS and Euro NCAP frontal offset occupant simulations. However during front crash simulations, it is very difficult to achieve good correlations or predictions of lower tibia loadings. A common issue is that the simulations often over-predict lower tibia loading (forces and/or moments) and in turn generate unrealistically higher tibia indices. For this reason, safety CAE engineers are not yet confident in presenting correlations or predictions of the lower tibia loadings/indices. This paper employs Pugh Concept Selection to study the effects of dummy foot location and carpet to sled buck floor interaction on the lower tibia loading/index response. Based on the understanding gained, improvements in the simulation fidelity of lower tibia indices were achieved. Additionally, these findings demonstrate that overall dummy performance is affected by the lower tibia index differences.
Li, Wei, Cheng, Yi-Pen, Furton, Lisa
Improved Seat Belt Restraint Geometry for Frontal, Frontal Oblique and Rollover Incidents2015-01-07404/14/2015
Throughout the first decade of the twenty first century, large improvements in occupant safety have been made in NASCAR®'s (National Association for Stock Car Auto Racing, Inc) race series. Enhancements to the occupant restraint system include the development and implementation of head and neck restraints, minimum performance requirements for belts and seats and the introduction of energy absorbing foam are a few highlights, among others. This paper discusses nineteen sled tests used to analyze hypothesized improvements to restraint system mounting geometry. The testing matrix included three sled acceleration profiles, three impact orientations, two Anthropomorphic Test Device (ATD) sizes as well as the restraint system design variables.
Patalak, John, Gideon, Thomas, Melvin, John W., Rains, Mike
Safety Belt Testing Apparatus2015-01-14854/14/2015
A new apparatus for testing modern safety belt systems was developed. The apparatus design, dynamic behavior and test procedure are described. A number of tests have been conducted using this apparatus. These tests allowed identification of key performance parameters of pretensioners and load limiting retractors which are relevant to occupant protection in a crash environment. Good test repeatability was observed, which allowed comparison of different safety belt designs. The apparatus may be used for better specification and verification of safety belt properties on a subsystem level as well as for the validation of CAE models of safety belts used in simulations of occupant response to crash events.
Kral, Jiri, Kondel, Theresa, Morra, Mark, Cassatta, Stephen, Bidolli, Peter, Stebbins, Patrick, Joshi, Vikas
Evaluation of Air Bag Electronic Sensing System Collision Performance through Laboratory Simulation2015-01-14844/14/2015
Since their inception, the design of airbag sensing systems has continued to evolve. The evolution of air bag sensing system design has been rapid. Electromechanical sensors used in earlier front air bag applications have been replaced by multi-point electronic sensors used to discriminate collision mechanics for potential air bag deployment in front, side and rollover accidents. In addition to multipoint electronic sensors, advanced air bag systems incorporate a variety of state sensors such as seat belt use status, seat track location, and occupant size classification that are taken into consideration by air bag system algorithms and occupant protection deployment strategies. Electronic sensing systems have allowed for the advent of event data recorders (EDRs), which over the past decade, have provided increasingly more information related to air bag deployment events in the field. To further aid in the evaluation of air bag field performance and interpretation of EDR downloads, a test methodology was developed so that controlled actuation of air bag system sensing elements could be achieved that accurately simulates vehicle collision dynamics. This was accomplished with the air bag control module removed from the vehicle and installed on physical actuators (linear and/or rotary) while still connected to the vehicle wiring harness. Controlled excitation of air bag sensing elements while simultaneously monitoring the outputs of the air bag system control module allows for assessment of system performance under various collision pulses and state sensor conditions. The presented test methodology provides a tool for evaluating field performance and EDR reporting in a controlled laboratory environment, without a priori knowledge of the underlying air bag algorithm or the expense and difficulty of running vehicle crashes.
Toomey, Daniel E., Winkel, Eric S., Krishnaswami, Ram
Sled Test Development and Occupant Protection Evaluation Based on the Frontal Crash Response of Heavy Trucks2014-01-24239/30/2014
Full-scale vehicle crash testing is an accurate method to reproduce many real-world crash conditions in a controlled laboratory environment. However, the costs involved in performing full-scale crash tests can be prohibitive for some purposes. Dynamic sled testing is a lower cost and widely used method to obtain multiple, useful data sets for development of frontal crash mitigating technologies, systems and components. Wherever possible, dynamic sled tests should use vehicle-specific deceleration pulses determined from full-scale vehicle crash tests. This paper establishes a dynamic sled test protocol based on data collected from eight full-scale heavy vehicle frontal crash tests. The sled test protocol is intended to be utilized as a basis for building a body of knowledge needed to update heavy vehicle frontal impact test recommended practices. These recommended practices provide direction for the development of frontal crash mitigating technologies, systems and components. Additionally, the performance of some frontal crash occupant protection technologies found in heavy vehicles is evaluated.
Chinni, James, Hoover, Ryan
Implementation and importance of ISOFIX and Latch System in the Brazilian Automotive Market2014-36-01659/30/2014
The increase in crash tests done for independent entities of consumer protection, such as the Euro NCAP (Europe) or IIHS (United States) have shown increasingly importance for safety regarding the occupant protection. The consumer of the automotive market in developed countries, as United States or countries of European Union for example, they seek for a safer vehicle when buying a new one. On the other hand in Brazil, the consumer does not have the culture of buying a vehicle thinking in safety performance, but they choose the cars because of body style and accessories. The regulation of the Brazilian government's obligation to Air Bag and ABS brakes for all vehicles produced in the country from January 2014 and the INOVAR AUTO program, aims to bring more safety to vehicles produced in the country. And certainly the ISOFIX system will be one of the items that should be implemented in the coming years, because the government agency INMETRO, has made the rules for child seats with ISOFIX system in January of this year and our neighbor Argentina also has already set the date for implementing the ISOFIX system on all cars produced there from 2018.The Latin NCAP, responsible to evaluate the vehicles in Latin America region, changed the scoring rules in the final of 2013. In order to a vehicle receive 5 stars in the child protection category, it will be necessary improve child restraint system. The alternative to improve can be the implementation of ISOFIX system, where its effectiveness has been proven through studies and tests, both in Brazil and abroad. An action of the OEM's in Brazil is expected towards including ISOFIX system as a standard in the new vehicles. Similar action is expected for child seats manufactures to meet these requirements. This paper was prepared to show the technical and financial impacts of child restraint seats (ISOFIX system) implementation, for the OEM's and for the consumers, showing their roles in vehicle safety in the Brazilian automotive market.
Marcial, Mauro, Pereira, André Luiz, Jr, Eduardo Orfale, Freitas, Rodrigo Martins, Yamada, William
A Methodology for Characterization of the Strain Rate-Dependent Behavior of PU Foam2014-01-05394/1/2014
Polymeric foams are known to be sensitive to strain rate under dynamic loads. Mechanical characterization of such materials would not thus be complete without capturing the effect of strain rate on their stress-strain behaviors. Consistent data on the dynamic behavior of foam is also necessary for designing energy-absorbing countermeasures based on foam such as for vehicle occupant safety protection. Strain rates of the order of 100-500 s−1 are quite common in such design applications; strain rates of this range cannot be obtained with an ordinary UTM (universal testing machine) and a special test set-up is usually needed. In the current study, a unique approach has been suggested according to which quasi-static tests at low strain rates and low velocity drop tests at medium strain rates are utilized to arrive at an empirical relation between initial peak stress and logarithm of strain rate for a rigid closed-cell PU foam. Using a stress-scaling methodology and the empirical relation mentioned, foam stress-strain curves are obtained for a number of strain rates spanning low (from 0.00033 s−1) to high strain rates (up to1000 s−1). This data on foam material behavior is expected to be particularly useful in numerical modelling of foam-based countermeasures for impact energy absorption applications.
Shivakumar, N., Deb, Anindya, Chou, Clifford, Chittappa, H.
Vehicle Restraint System Optimization for Frontal Impact2013-36-047310/7/2013
The Brazilian Automotive regulations that are aimed towards the safety of drivers, passengers and pedestrians have gone through recent changes to prevent and/or minimize injury and trauma from different types of accidents. Until now, National Traffic Council (CONTRAN) Resolution n° 14/98 required vehicles to only have safety belts for an occupant restraint system, and frontal airbags were not required. Since the recent CONTRAN n° 311/09 Resolution requires mandatory frontal airbags, the occupant restraint system must be tuned due to the interaction with different components that may make up the system, like safety belts with pretensioners and seatbelt load limiting devices. The present study was developed to optimize the restraint system of a current vehicle in production, while focusing on minimizing the vehicle complexity. The optimization tool helped to develop a robust restraint system for the frontal passenger during a frontal impact [1]. The numerical computational model created was initially correlated with an experimental test, and then 72 simulations were performed to build the optimization matrix. The optimized parameters provided by the Design of Experiments (DOE) were simulated in the numerical computational model and also applied in an experimental test. The results presented excellent correlation and the goals of the optimization were achieved showing that this tool can help in future developments. This paper will review the methods used to study variables in restraint system with respect to their effect on occupant performance, as well as explain the final results from this optimization study.
Rosa, Mateus A. Santa, Callaghan, Brian, Guido, Carlos A. Prado, de Lima, Anderson
Life RaftsARP1356B (Current)5/21/2013
This Aerospace Recommended Practice (ARP) establishes criteria for the design and performance of aircraft life raft devices which will ensure their rapid and effective use as a flotation device in a water landing. This document is not intended to specify particular design methods, mechanisms, or equipment to be used to accomplish the objectives established herein.
S-9A Safety Equipment and Survival Systems Committee
SAE Child Passenger Safety GlossaryJ2939_201304 (Historical)4/9/2013
Children's Restraint Systems Committee
Examination of a Properly Restrained Motorsport Occupant2013-01-08044/8/2013
Throughout the first decade of the twenty first century, large improvements in occupant safety have been made in NASCAR®'s (National Association for Stock Car Auto Racing, Inc.) race series. Enhancements to the occupant restraint system include the implementation and advancement of head and neck restraints (HNR), minimum performance requirements for belts and seats and the introduction of energy-absorbing foam are a few highlights, among others. This paper summarizes three non-injury case studies of actual on-track incidents, including the acceleration pulses, principal direction of force, restraint systems used and driver anthropometry information. Also discussed are the NASCAR personal safety equipment requirements as well as frontal, oblique and side sled testing data of similar input acceleration magnitudes for the Hybrid III (H-III) fiftieth percentile male anthropomorphic test device (ATD).
Patalak, John, Gideon, Thomas, Melvin, John
Side Crash Pressure Sensor Prediction for Unitized Vehicles: An ALE Approach2013-01-06574/8/2013
With a goal to help develop pressure sensor calibration and deployment algorithms using computer simulations, an Arbitrary Lagrangian Eulerian (ALE) approach was adopted in this research to predict the responses of side crash pressure sensors for unitized vehicles. For occupant protection, acceleration-based crash sensors have been used in the automotive industry to deploy restraint devices when vehicle crashes occur. With improvements in the crash sensor technology, pressure sensors that detect pressure changes in door cavities have been developed recently for vehicle crash safety applications. Instead of using acceleration (or deceleration) in the acceleration-based crash sensors, the pressure sensors utilize pressure change in a door structure to determine the deployment of restraint devices. The crash pulses recorded by the acceleration-based crash sensors usually exhibit high frequency and noisy responses. Different from those of the acceleration-based crash sensors, the data obtained from the pressure sensors exhibit lower frequency and less noisy responses. Due to its ability to discriminate crash severities and allow the restraint devices to deploy earlier, the pressure sensor technology has gained its popularity for side crash applications. The lower frequency and less noisy characteristics are also more suitable for non-linear finite element codes to predict. Fifteen different benchmark problems were designed and tested in the first stage of this research to investigate the responses of pressure sensors in different impact conditions and the capabilities of the ALE method in the predictions of different pressure sensor responses. The fifteen benchmark problems were divided into three groups to examine the capabilities of the ALE method in detail. Different structures, gases, hole locations, sensor locations, hole sizes, impact speeds, and impactors, were chosen in the fifteen benchmark problems so that the sensitivity of the pressure responses to different factors could be obtained and understood. Computer simulations conducted by employing the ALE method for all fifteen benchmark problems were compared to their corresponding theoretical solutions or test data. The correlations between the tests and the computer simulations were found to be reasonable as reported in a paper published previously. The research was advanced into its final stage, full vehicle tests, after the positive results obtained from the benchmark study. The full vehicle study included two major vehicle architectures, body-on-frame and unitized, that are commonly used to design vehicles in the automotive industry. This paper focuses on the unitized vehicles. A total of thirteen tests, including different body styles, powertrains, drivetrains, test modes, and impact speeds, were investigated. A simulation methodology was developed in this study to correlate the structural responses and to predict the pressure sensor responses for unitized vehicles. The results obtained from the developed methodology using the ALE simulations are compared to those obtained from the corresponding tests. In the full vehicle study, low speed impact conditions were found to be more challenging to predict compared to those of the high speed impact conditions. This is because the pressure responses for the low speed impacts are usually much weaker than those of the high speed impacts. The numerical errors obtained from the simulations become more significant when the magnitudes of the pressure responses are low. The numerical errors induced by the coupling of Lagrangian and Eulerian calculation need to be distinguished and ignored (or filtered) when processing the pressure information. The slopes, peak values, and overall shapes of the predicted pressure responses correlate reasonably with most of the full vehicle tests selected. The correlations of the pre-peak responses are better than those of the post-peak responses which involve air leakage. The oblique pole, IIHS MDB, and FMVSS 214 MDB test modes create distinct door deformations and pressure responses which can be predicted by the computer simulations reasonably. Sensor engineers analyzed the results obtained from a FMVSS 214 simulation and confirmed that replacing the test data with the predicted results would result in the same deployment algorithm.
Tyan, Tau, Arthurs, Kirk, Rupp, Jeffrey, Parks, Melissa, Mahadevan, Kumar, Barbat, Saeed, Kochhar, Nand, Fazio, John, Bauch, David
Severe Frontal Collisions with Partial Overlap - Two Decades of Car Safety Development2013-01-07594/8/2013
Frontal Severe Partial Overlap Collisions (SPOC) also called small overlap crashes pose special challenges with respect to structural design as well as occupant protection. In the early 1990s, the SPOC test method was developed addressing 20-40% overlap against a fixed rigid barrier with initial velocities up to 65 km/h. The knowledge gained has been used in the design of Volvo vehicles since then. Important design principles include front side members orientated along the wheel envelopes together with a strong support structure utilizing a space frame principle with beams loaded mainly in tension and compression. This novel setup was first introduced in the 850-model in 1991 and has been refined and patented (2001) in later Volvo front structures. Among the design principles are multiple front side members on each side, helping energy absorption efficiency and robustness. The upper side members absorb energy and also transfer the forces via the A-pillars into the roof and the reinforced body and door structures. The lower side members are connected by a cross member with balanced design combining strength and energy absorption using truss principles. The overall design is made to address loads in multiple directions as well as mitigate front wheel intrusion into the passenger compartment. Real world data, complemented with laboratory testing, show that the improvements have substantial effect on occupant protection, reducing overall injuries over the years and reducing footwell intrusion related injuries specifically.
Jakobsson, Lotta, McInally, Graeme, Axelson, Anders, Lindman, Magdalena, Kling, Anders, Broberg, Thomas, Fermér, Mikael, Wågström, Linus
Robust Design in Occupant Safety Simulation2013-01-01233/25/2013
Explicit FE-simulation has become a standard design tool in passive safety development as it can help to reduce the number of vehicle prototype tests, especially in the early project stages. Due to fewer hardware tests available as sources of validation, the expectations towards predictability of dummy injury occurrence have strongly increased. To produce robust results, virtual passive safety analysis has to take real uncertainties of test condition and their probabilistic effects upon the system's response into account. Findings by simulation therefore should not be regarded anymore as single point statements in a pure deterministic approach. They rather need to be extended into statements upon grades of correlation between individual system parameters taking into account their stochastic nature. This paper illustrates a process for complete robustness analysis in occupant safety simulation. It introduces techniques to document statistical confidence intervals of the correlations determined, and uses statistical “bootstrapping” in populations where only a limited number of samplings can be generated. Finally, by regression analysis within the reduced relevant physical parameter space, a risk assessment upon a potential failure within the specific test requirements is carried out. Identification of initial design space parameters requires experience and proper preparation when one is conducting statistical analysis on occupant safety. This work explains relevant design space parameters for a typical full vehicle test and classifies them in proper ways since obtaining their sampling often requires additional pre-simulation efforts. In this context a number of in-house tools are highlighted here that helps the designer in obtaining work intensive design parameters such as the distribution of dummy, seat & belt positions. The entire robustness design process uses automated work flows and tools to visualize the statistical data observed since the simulation model complexity and its computational costs are extremely high. Finally, the gained correlations are discussed, interpreted and explained in terms of real life phenomenon that can be observed in testing.
Brix, Claudius, Tok, Chye Hock
Performance Driven Package Feasibility of Side Restraints Using KBE Tools2013-26-00271/9/2013
Integrating safety features may lead to changes in vehicle interior component designs. Considering this complexity, design guidelines have to take care of aspects which may help in package feasibility studies that consider systems performance requirements. Occupant restraints systems for protection in side crashes generally comprise of Side Airbag (SAB) and Curtain Airbag (IC). These components have to be integrated considering design and styling aspects of interior trims, seat contours and body structure for performance efficient package definition. In side crashes, occupant injury risk increases due to hard contact with intruding structure. This risk could be minimized by cushioning the occupant contact through provision of SAB and Inflatable IC. This paper explains the methodology for deciding the package definitions using Knowlwdge Based Engineering (KBE) tools. The logic in the applications helps to generate package layout requirements for airbag module configurations as well as interior components. The protection zones for occupant body regions such as thorax for SAB and head for IC could be defined using the applications. The location of chambers to be inflated for protection could be arrived at thereby providing extent of airbag envelope required. The variations arising out of occupant anthropometry, seating attitude have also been considered. Package clearance requirements with interfaces like side door and pillar trims, seat belts, could be identified. Package constraints for hard components which increase occupant injury risk can also be defined. The requirements to ensure stable deployments, particularly for IC, could also be analyzed. The application outputs are available as summary reports, data which could be further used by design teams. The applications have been successfully validated on vehicle programs.
Chavare, Ajay P., Khare, Pratyush, Bhise, Amit, Belanke, Prreya
Operator Protection for General - Purpose Industrial MachinesJ1042_201206 (Current)6/29/2012
This SAE Standard applies to General-Purpose Industrial Machines described in Category 2 of SAE J1116, but excludes skid steer loaders (covered by SAE J1388). Protection for the operator of an attachment (for example, a backhoe) is excluded from the scope of this document.
OPTC1, Personnel Protection (General)
Biomechanics of Occupant Responses during Recreational Off-Highway Vehicle (ROV) Riding and 90-degree Tip-overs2012-01-00964/16/2012
Recently, side-by-side Recreational Off-Highway Vehicles (ROVs) have brought elements of the on-road vehicle occupant environment to the off-road trail-riding world. In general, ROV occupant protection during normal operation and in accident scenarios is provided predominately by a roll cage, seatbelts, contoured seats with seat backs, handholds, and other components. Typical occupant responses include both passive (inertial) and active (muscular) components. The objective of the current study was to evaluate and quantify these passive and active occupant responses during belted operation of an ROV on a closed course, as well as during 90-degree tip-over events. Passive occupant responses were evaluated using anthropomorphic test devices (ATDs) in 90-degree tip-overs simulated on a deceleration sled. Active occupant responses were evaluated using instrumented vehicles and volunteer occupants, wherein vehicle dynamics and gross occupant kinematics, muscle activity, occupant-to-vehicle pressure distributions and forces were quantified during riding on a closed course and during 90-degree tip-overs in a roll-spit fixture. For comparison, each test subject also performed a series of common physical activities while instrumented. Results indicated that the seatbelt was a critical component to the occupant protection system and that belted occupants were passively maintained within the occupant compartment during 90-degree tip-over events. Results also demonstrated that the active responses of the occupants further contributed to occupant stability and correlated significantly with the vehicle's lateral acceleration. Changes in patterns of muscle activation occurred approximate with the vehicle's change in turn direction and indicated a clear push-pull strategy of the occupant during left and right turns, respectively. Roll-spit testing demonstrated that the majority of lateral restraint was provided by the bucket seat, wherein modest lap belt forces constrained the pelvis within the seat contour and facilitated the generation of lateral contact forces. Forces exerted by occupants' extremities on the vehicle during a 90-degree tip-over were comparable to, or less than, the forces resulting from common physical activities.
Newberry, William, Carhart, Michael, Larson, Robert, Bridges, Amanda, Fowler, Graeme
Injury Risk Investigation of the Small, Rear-seat Occupant in Side Impact2012-01-00924/16/2012
For children seated next to the struck side, real-world crash outcome was determined for the rear-seat of passenger vehicles over the entire range of side impact crash severities. The method was first to calculate the actual risk for an occupant based on field data. The data sources were non-rollover, tow-away crashes from the 1997 - 2009 National Automotive Sampling System. By limiting the struck passenger vehicle to model year 1985 or newer, field data were identified for a total of 588 children. In all crashes, the child was seated in the rear-seat area on the struck side of the passenger vehicle. A matrix of MADYMO model simulations calculated the response of child dummies over the entire range of the field data. Age-dependent, moderate-to-serious (AIS ≥ 2) injury risk curves were derived and evaluated for children in side impact. Risks to the children were calculated by combining the derived child risk curves with the MADYMO model simulations. The evaluations were conducted from the point of view of an aggregate approximation of AIS ≥ 2 injury rates across the crash severity range for the entire child group of all ages. The results were that the simulations and biomechanical injury risks reasonably matched the actual NASS-CDS-based trauma risks. For all children, the accumulated injury risk approximation was 10.66% and the field-based approximation was 10.73%. This field-based methodology focuses occupant safety design toward a more far-reaching system approach where the entire range of side-impact crash severities and occupant variability are considered.
Morgan, Richard M., Scullion, Paul, Nix, Lilly, Kan, Cing-Dao, Nagabhushana, Vinay, Shanks, Kurt, Tangirala, Ravi
Headform Impact Tests to Assess Energy Management of Seat Back Contact Points Associated with Head Injury for Pediatric Occupants2012-01-05614/16/2012
Head injuries are the most common injuries sustained by children in motor vehicle crashes regardless of age, restraint and crash direction. Previous research identified the front seat back as relevant contact point associated with head injuries sustained by restrained rear seated child occupants. The objective of this study was to conduct a test series of headform impacts to seat backs to evaluate the energy management characteristics of relevant contact points for pediatric head injury. A total of eight seats were tested: two each of 2007 Ford Focus, Toyota Corolla, 2006 Volvo S40, and 2008 Volkswagen Golf. Five to six contact points were chosen for each unique seat model guided by contact locations determined from real world crashes. Each vehicle seat was rigidly mounted in the center track position with the seatback angle adjusted to 70 degrees above the horizontal. A 3.5 kg child pedestrian headform was fired at a velocity of 24 km/h (6.67 m/s) in accordance to FMVSS 201 at 22 degrees above the horizontal starting from 10 cm from the center of the target. Resultant acceleration and HIC (15 ms and 36 ms) were calculated for each impact. Within the class of small family vehicles, there was substantial variation in underlying seat structure across the locations of head impact identified in the case series resulting in a wide range of maximum resultant head acceleration - 27-165 g. Several impact locations, particularly those around the edge of seat back resulted in head acceleration greater than 80g used in regulatory tests. These data highlight the need to re-examine the current FMVSS 201, Occupant Protection in Interior Impact, to account for the typical impact locations of child occupants in crashes. In addition, further study is needed to understand the tolerance of the pediatric skull and brain to these types of impacts.
Arbogast, Kristy B., Maltese, Matthew R., Locey, Caitlin, Bohman, Katarina
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