Browse Topic: Seats and seating

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Development and Flight Demonstration of An Active Seat Mount System for Aircrew Whole-Body Vibration Mitigation on NRC Bell-412 HelicopterF-0080-2024-10415/7/2024
Helicopter aircrew are exposed to high levels of whole-body vibration (WBV) in fight operations, which may degrade their ride comfort and performance in the short-term, and contribute to some health issues in the long-term. This paper presents the latest development and flight test demonstration results of an active seat mount system that is designed to reduce helicopter aircrew WBV levels through active cancellation of the N/rev vibration peaks related to the helicopter main rotor speed. A prototype airworthy hardware of the active seat mount system has been developed based on previous bench-top-test designs to meet airframe integrity requirements for installation and flight testing on the Bell-412 helicopter. Extensive experimental results on human occupants using a shaker table facility and flight demonstrations on the NRC Bell-412 helicopter in representative flight conditions are presented and discussed. The active seat mount system has achieved significant reduction to the occupant WBV levels at the bottom seat cushion interface per ISO2631/MIL-STD-1472G metrics, and also showed effective mitigation to the occupant head vibrations. These investigations demonstrate that the active seat mount technology is a feasible solution for helicopter aircrew WBV mitigation.
Chen, Yong (Eric), Wickramasinghe, Viresh, Fereidooni, Amin
Haptic Device Embedded in Rotorcraft Seats to Provide Motion Onset Cues in Flight SimulatorF-0080-2024-12645/7/2024
This paper describes development and testing of a low-cost device mounted on in the pilot seat of a rotorcraft simulator with the aim of improving the perceived realism of the flight. The device acting vertically from the bottom of the seat is used to communicate changes of acceleration in the vertical direction corresponding to heave movement of the simulated aircraft. A bespoke flight simulator system was developed, featuring modular design and virtual reality (VR) visualisation to enable comparative testing with a full motion system. Objective analyses have shown similarities between the two motion cueing configurations when contrasted with only using visual cues.
Lukasiewicz, Marek, Quaranta, Giuseppe, Zanoni, Andrea
Development and Demonstration of a Critical Rotorcraft Safety System: Advanced Helicopter Seating SystemF-0080-2024-11955/7/2024
The Advanced Helicopter Seating System (AHSS) was started as an effort to evaluate and improve the current state of military rotorcraft seating. The overall goal of the program has been to improve pilot ergonomics and safety through the integration of advanced energy absorption and vibration reduction mechanisms as well as a broad approach to system integration based around updated occupant anthropometrics. An entirely new seating solution has been developed, with intent to integrate with the AH-64 Apache platform for demonstration purposes. The AH-64 development culminated with a series of static tests and dynamic test events to measure the effectiveness of the safety systems integrated on the seat as compared to the legacy AH-64 seating system. While lumbar load data and seat stroke data was obtained, issues with the anthropomorphic test device (ATD) configuration at the 95th male configuration caused some data to be suspect, and premature failure of several components also caused loss of capturing accurate data. Lessons learned are documented in the conclusions. Data and lessons learned from this effort are being used to support a follow-on effort to develop a pilot seat for the UH-60 Black Hawk Platform.
Minton, Tyrone, Crocco, John, Richards, Marvin
Anthropometric Accommodation and Ergonomics in the MH-60S NextGen Gunners SeatF-0077-2021-167495/10/2021
ABSTRACT
Basham, Lori, Blankenship,  Justin, Koch,  Andrew
Spinal Injury Risk Associated with Performance Requirements for Military Rotary-Wing SeatsF-0077-2021-167565/10/2021
ABSTRACT
Lafferty, Elizabeth, Chancey, Valeta, Flath,  Nathan, McEntire,  Barney
Development of an Improved Gunner Seat RestraintF-0077-2021-167575/10/2021
ABSTRACT
Podob, Roger, Druff, Charles
The Effect of Change in Assembly Sequence on Permanent Strain of Cab Suspension Console02-13-02-00118/20/2020
Heavy commercial vehicles play an important role in creating the trade and economic balance of countries. Also, the durability and safety of heavy commercial vehicles come to the fore. Heavy commercial vehicles consist of two parts. These are the chassis area with the equipment that allows the vehicle to move and the cabin section where the driver is located. The cabin area is the most important area that ensures the highest level of driver safety. Considering that the production of trucks is increasing day by day, it is inevitable for companies to increase their R&D activities in the field of cabin and cabin suspension systems for much safer, durable, and comfortable trucks. This study aims to determine the safe torque value of the fasteners and their assembly sequence of the Cab Suspension Console, which is one of the most important connection parts in a truck and which can cause a fatal accident by breaking. In this study, the safe torque value of the fasteners of the cabin suspension console has been determined as 180 ± 15 Nm/180 ± 10 Grad for the outer fasteners and 225 ± 18 Nm/180 ± 10 Grad for the inner fasteners. In addition, two different assembly sequences are determined and permanent strains on the part are measured. At the end of the assembly test, permanent strains on the part and other factors affecting the strain are simulated. According to the results obtained, the assembly sequence with a low permanent strain value is chosen and commissioned in production.
Yildirim, Bariscan, Öztürk, Dogan
Motor Vehicle Seat DimensionsJ2732_202007 (Current)7/1/2020
This document provides dimensional definitions that facilitate geometric quantification and evaluation of seats. Linear, radial, and angular surface dimensions included in this document are intended to approximate shape characteristics based on defined points of interest and not as a method needed to reproduce complex surface contours. In many cases, other points across the seat surface shape may exceed or not reach the boundary defined by these simple geometric definitions. Dimensions described in this document have been designed to be measured in a CAD environment; however, many dimensions require the HPD position and attitude. This can be obtained by physically establishing H-point using benchmark or auditing procedures OR by measuring the HPD within a CAD or modelling system. Refer to the appropriate document for these procedures. Three types of seat geometry reference points and measurements have been developed: 1 Simple reference points and measurements not related to H-point. 2 H-point dependent reference points and measurements that utilize the seat characterization capabilities of the HPD to quantify seat measurements. 3 Cross-sectional seat trim outlines. For convenience and simplicity, many terms associated with H-point devices use human body parts in their name. However, they should not be construed as measures that indicate interaction with any or all occupants concerning accommodation, human capabilities, or comfort. H-point devices do not represent the size or posture of any category of occupant.
Human Accom and Design Devices Stds Comm
The Effects of Small Seat Swiveling Angles on Occupant Responses during a Frontal Impact2020-01-05714/14/2020
In highly automated vehicles (HAVs), new seat configurations may be desirable to allow occupants to perform new activities. One of the current HAV concepts is the swiveled seat layout, which might facilitate communication between occupants. The main objective of this study was to investigate the effects of seat swiveling angles on occupant kinematics and injury risk predicted by a Human Body Model (HBM) during a frontal impact. A detailed 50th percentile male HBM (GHBMC M50-O) was subjected to two frontal crash pulses in a sled setup. The model was positioned on a semi-rigid seat and restrained using a pre-inflated airbag and a three-point seatbelt. Simulations included four seat swiveling angles (0, -10, -20, and -30 degrees), three occupant positions (Sedan driver, large VAN driver or Laptop user), two airbag initial locations (nominal or matching the head Y location), and the inclusion of lateral supports on the seat pan. The effects of the seat swiveling angle were similar for all occupant positions. With the airbag in the nominal location, higher seat swiveling angles led to a higher head lateral displacement and a higher risk of head injury, especially for the BrIC criterion. The Sedan driver position had higher BrIC and a larger head lateral excursion than the other two positions. This could be mitigated by aligning the airbag location with the head. Pelvic fractures were also predicted for the configurations with the highest swiveling angles. These fractures were limited by the use of seat pan lateral supports. Overall, the model responses were sensitive to both seating configurations and occupant postures, and the results suggest that swiveled seating may increase the injury risk, especially for the head and pelvis. However, simple countermeasures, such as adapted airbag location or adding lateral seat pan supports, seemed possible to mitigate the risk.
Grébonval, Cyrille, Trosseille, Xavier, Petit, Philippe, Wang, Xuguang, Beillas, Philippe
Create the Future Contest Idea Saving LivesTBMG-361613/1/2020
The Create the Future Design Contest was launched in 2002 by the publishers of Tech Briefs magazine to help stimulate and reward engineering innovation. The annual event has attracted more than 14,000 product design ideas from engineers, entrepreneurs, and students worldwide.
Design Guidelines for Fiberboard MaterialsJ1774_201909 (Current)9/25/2019
This document provides information on the various fiberboard products, which are available for automotive application. It is intended to give engineers and designers a better understanding of product usage, characteristics, properties and industry terminology. The following sections cover these topics: 2 General Product Information 3 Design Characteristics 4 Physical/Mechanical Properties 5 Fiberboard Definitions In sections 2, 3 and 4 the fiberboard products are categorized. These sections give an overview of product types, with general information about characteristics and properties. In cases where product categories encompass more than one material or material grade, ranges were established to cover all of the products in that category. The individual companies that supply fiberboard products should be consulted for specific information about a particular product or application.
Textile and Flexible Plastics Committee
WHAT WE'RE DRIVING19AUTP09_089/1/2019
As the sporting player in Volvo's C-segment sedan lineup, this all-wheel drive, turbocharged-and-supercharged R-Design S60 faces benchmark competition in the BMW 3-Series, Audi A4 and Mercedes-Benz C-Class. In pure performance, the stylish Swede stacks up nicely against the Germans: Its 316 hp (236 kW) pushes the 3,900 lb (1769 kg) car plus my 200-lb (91 kg) of dead weight from a standstill to 60 mph (97 km/h) in 5.5 s, according to my stopwatch. Dynamically, the S60 T6 (not my choice of nomenclature, as it's a 4-cyl., not a six) feels solid and secure, if not exceptionally nimble, when pushed hard in the corners. But where the S60 R-Design clearly beats the others is inside, the area where Volvo shows its taillamps to the other premium brands. The S60's cabin is a beautifully integrated blend of rich materials and tasteful accents - brushed aluminum of the lower IP contrasting with deep ebony, offset by delightful-to-touch control knobs. The front seats are both handsome and comfortable. Rear-seat legroom is excellent, as my 37-in. (940-mm) inseam can attest.
Gaining Approval for Seats with Integrated Electronics in Accordance with AC21-49 Option 7bAIR6448A (Current)8/7/2019
The primary purpose of this document is to provide roles, responsibilities and accountabilities to meet AC 21-49 Section 7.b ‘Type Certification using TSO-approved seat with electronic components defined in TSO design’. This document may be applied to all applicable seat TSOs (C39(), C127()…etc). The approval for the integration of the electronics will fall, in part or in full, under the type design authority of the Seat Installer rather than the Seat Supplier shipping the integrated seat. The defined responsibilities, areas of authority and accountability of each party, as well as necessary communication protocols, must ensure configuration management, design control and quality control. These definitions, controls and protocols are agreed (thru normal commerical agreements and binding contracts) and adhered to by all parties ensuring all parts in the supply chain remain approved (e.g. certified and conformed).
Aircraft SEAT Committee
Comparison of Measurement Methods for Evaluating Displacement of Commercial Vehicle Seats2019-01-14816/5/2019
Measuring the displacements in vehicle seat suspensions and the displacements the seat has to absorb may assist vehicle seat designers in better designing seats to absorb vibrations. Low frequency seat displacement is important in seat design to identify end-stop events and higher frequency shorter displacements are also important since seat components can be optimized to absorb these smaller displacements. Displacements can be directly measured with special instruments, but it would be less complicated if simple, compact accelerometers could be used to measure the seat displacements. This paper compares accelerometer-derived displacement measurements to known displacements derived from sinusoidal physics and field measured random displacements measured with potentiometers. Using known, controlled sinusoidal displacements, three lab-based experiments were conducted to determine how well accelerometers, using double integration, could measure displacements. In addition, using a vehicle travelling on four different road types, the capability of accelerometers measuring random displacement was assessed. In general, the accelerometer-derived displacements matched the known sinusoidal displacement in the lab settings and the potentiometer measured displacements in the field; however, limitations were identified. First, the frequency bandwidth of the accelerometers can be a limitation. Most accelerometers are limited in their ability to measure low frequency vibrations (0 - 3 Hz) so MEMS-based accelerometers with DC resolution may facilitate better capture of the low frequency displacements. Second, the direct displacement measurements need to be more robust. Potentiometers can be prone to errors due needed signal filtering and additional errors if not correctly mounted and calibrated. With the uncertainty associated with displacement measurement, more systematic evaluation is needed to determine the viability of various transducers for measuring absolute and relative vehicle seat displacements.
Haylett, James, Johnson, Peter
Analyzing Field Environments to Understand Product Failure Causes2019-01-14776/5/2019
Product failures often require expensive repairs or replacements. Over-engineering adds to recurring costs and its success is uncertain if the failure’s cause is not understood. Engineers need in-depth knowledge before attempting a re-design. This case study focuses on bus seat failures that occasionally occur in the field but are not predicted by current industry standard tests in the lab. The goal was to collect comprehensive field vibration data and analyze that data to understand the failure’s causes. The study used accelerometers placed at various points in multiple seating configurations and across multiple field environments. Analysis identified transmissibility issues between axes of motion, as well as a seat configuration with higher reliability.
Vande Kamp, Jade
Towards a Quiet Vehicle Cabin Through Digitalization of HVAC Systems and Subsystems Aeroacoustics Testing and Design2019-01-14766/5/2019
With the rise of electric autonomous vehicles, it has become clear that the cabin of tomorrow will drastically evolve to both improve ride experience and reduce energy consumption. In addition, autonomy will change the transportation paradigm, leading to a reinvention of the cabin seating layout which will offer the opportunity to climate systems team to design quiet and even more energy efficient systems. Consequently, Heat and Ventilation Air Conditioning (HVAC) systems designers have to deliver products which perform acoustically better than before, but often with less development time. To success under such constraints, designers need access to methods providing both assessment of the system (or subsystems) acoustic performance, and identification of where the designs need to be improved to reduce noise levels. Such methods are often needed before a physical prototype is requested, and thus can only be achieved in a timely manner through digital testing. Previous studies have demonstrated the ability of a CFD/CAA approach based on the Lattice Boltzmann Method (LBM) to predict HVAC system noise including real and complex ducts, registers, mixing unit and blower geometries. This LBM low dissipative numerical approach has indeed been shown to accurately capture turbulent and convective mechanisms and to propagate acoustic waves in ducted systems and in free-field. Combined with a noise source identification strategy, these methods provide the ability to visualize the noise sources inside the system, as well as to identify and rank noise-generating design features - a unique design methodology not available with physical testing. In this paper, such an approach is presented based on two HVAC systems layout, targeting two different vehicles. To answer the need for systems and subsystems predictions, simulation results are correlated to experiment for configurations with blower alone, blower + air intake, and for full HVAC system (blower + air intake + mixing unit). Finally, an in-depth analysis of the flow noise sources contributions to a microphone location is performed, and countermeasures are discussed.
Vidal, Vincent, Mann, Adrien, Verriere, Jonas, Kim, Minsuk, Ailloud, Fabrice, Henner, Manuel, Cheriaux, Olivier
H-Point Machine (HPM-II) - Procedure for H-Point Determination - Benchmarking Vehicle SeatsJ4003_201904 (Current)4/25/2019
Benchmarking is used to discover the design intent measurements for seating compartments in vehicles when these measurements are either unknown or are specified using differing measurement procedures. This document provides the specifications and procedures to establish consistent measurements for benchmarking vehicle seating positions using the H-Point Machine (HPM-II1) described in SAE J4002 and the H-Point Design tool (HPD) described in SAE J4004. The HPM-II is a physical tool used to establish key reference points and measurements in a vehicle (Figure 1). The HPD is a CAD tool that aids in the benchmarking process (see Appendix A and SAE J4004).
Human Accom and Design Devices Stds Comm
Comparison Study of Malaysian Driver Seating Position in SAEJ1517 Accommodation Model06-12-02-00064/8/2019
A key element in an ergonomically designed driver’s seat in a car is the correct identification of driver seating position and posture accommodation. Current practice by the automotive Original Equipment Manufacturer (OEM) is to utilize the Society of Automotive Engineering (SAE) J1517 standard practice as a reference. However, it was found that utilizing such guidelines, which were developed based on the American population, did not fit well with the anthropometry and stature of the Malaysian population. This research seeks to address this issue by comparing the SAE J1517 Model against Malaysian preferred driving position. A total of 62 respondents were involved for the driver seating position and accommodation study in the vehicle driver’s seat buck mockup survey and measurements. The results have shown that the Malaysian drivers prefer to sit forward as compared to the SAE J1517 Model and have shorter posture joint angle. This could significantly affect the design of the driver seat positions and layout of other driving elements, suggesting a need to reconsider its application, in particular for the Malaysian population.
Rashid, Zuli’zam, Bakar, Nooh Abu, Dolah, Rozzeta, Ghazilla, Raja Ariffin Raja
FRED II Quasistatic Seat Testing Rearward: An Improved Method Based on the SAE H-point Manikin2019-01-10324/2/2019
Various methods have been used to load a seat in the rear direction, including FMVSS 207, assorted body blocks and QST (quasistatic seat test). However, each method lacks some critical aspect of occupant loading of the seat or is too complex for routine development work. A new method is presented to determine the strength and energy transfer of a seat to an occupant in rear impacts that reflects how an occupant interacts with the seat in a rear impact. A metal-cast H-point manikin, called FRED II, was modified to support a loading bar and was pulled rearward into the seatback by a hydraulic ram. The force and displacement of the loading and the inboard and outboard seatback angle were measured. The response of the seat was recorded by video. The moment about the recliner pivot at peak force was determined by aligning the center of the recliner in side views of the seat position initially and at peak load. The height of the cable above the center of the recliner was determined giving the moment arm at peak load. The force was integrated with displacement to determine energy transfer to the seat. Twelve tests were performed with FRED II and twelve with a traditional body block used by CRA. There were nine matched tests with identical seats. With FRED II, the average peak moment was 2,407 ± 460 Nm and the energy transfer was 2,046 ± 531 J. With the body block, the average peak moment was 2,534 ± 297 Nm using the same method to determine the moment at peak force and the energy transfer was 1,740 ± 379 J. FRED II loads the seatback as the Hybrid III dummy does in sled tests. It measures the energy transfer capability of the seat in a manner that is similar to occupant loading in a rear impact. FRED II is a simple and improved quasistatic method for seat testing. FRED II provides the H-point location and can be used to measure head restraint position.
Viano, David, Burnett, Roger, White, Samuel
Vibration Control of an Active Seat Suspension System Integrated Pregnant Woman Body Model2019-01-01724/2/2019
Proportional-integral-derivative (PID) controller is effective, popular and cost effective for a lot of scientific and engineering applications. In this paper, PID and fuzzy-self-tuning PID (FSTPID) controllers are applied to improve the performance of an active seat suspension system to enhance the pregnant woman comfort. The equations of motion of thirteen-degrees-of-freedom (13-DOF) active seat suspension system incorporating pregnant woman body model are derived and simulated. PID gains are tuned and estimated using genetic algorithm (GA) to formulate GA PID controller. In FSTPID, fuzzy logic technique is used to tune PID controller gains by selecting appropriate fuzzy rules using Matlab/Simulink software. Both controlled active seat suspension systems are compared with a passive seat suspension. Suspension performance is evaluated under bump and random road excitations in order to verify the success of the proposed controllers. Theoretical results reveal that the proposed controllers using GA PID and FSTPID grant a significant enhancement of the pregnant woman comfort and her fetus.
Ali, Shaimaa A., Metered, H., Bassiuny, A. M, Abdel-Ghany, AM
Effect of Fabric Parameters on Phenomena of Electrostatic Charge Generation2019-01-04644/2/2019
Electrostatic charge generation in fabric is a common phenomenon. This phenomenon of charge generation & transfer of the same to human body is more in case of fabrics made of polyester yarns due to interface property of the material. The charge generation may result in attraction of dust on the fabric surface, clinginess & may also result in uncomfortable shock to the human body. This situation is attributed to various parameters such as fabric construction, yarn properties, yarn finish & various coating on the yarn. Since, polyester fabric is prime material used in seating; there have been many incidences of rubbing of seat fabric to human body, resulting in generation of static charge. This study focuses on understanding the effect of various fabric parameters on electrostatic charge generation. The study will also look into various potential solutions to reduce the charge generation with their merits and demerits.
Kumari, Sarita, Maheshwari, Pankaj
Seat Performance and Occupant Moving Out of the Shoulder Belt in ABTS (All-Belts-to-Seat) in Rear Impacts2019-01-10314/2/2019
This study examined occupant and seat responses with ABTS (all-belts-to-seat) in rear end collisions. Some have claimed improved ABTS seat performance and retention in rear impacts than conventional seats. ABTS seats tend to have higher ultimate yield strengths than conventional yielding seats. Most ABTS seats have asymmetric seatback stiffness due to the need for additional structure on one side of the seat to support shoulder belt loads. Many designs use a single-side recliner and single stanchion that anchors the D-ring. This asymmetry results in twisting of the seatback in severe rear impacts. Seatback twist can allow the occupant to move away from the shoulder belt. Rearward pull tests on ABTS seats also demonstrates seatback twisting and in some cases large drops in load during the test. The added strength and stiffness of ABTS seats lead to designs that are vulnerable to sudden force drops from separated parts.
White, Samuel, Viano, David, Burnett, Roger
An Experimental Investigation of Squeak Noise for the Fabric and Plastic of Automotive Seat2019-01-14293/25/2019
Recently, one of major problems in automotive industry is squeak noise between two different materials. It is the most severe case that the noise between automobile seat and other relative parts (or within seat parts). Especially, seat covering is generated to unfavorable sound by friction of other parts. The purpose of this research is to verify and suggest a way to reduce squeak noise between seat covering and plastic at relative parts. Test results were reported with 1 to 10 Risk Priority Number (RPN) which was proposed by VDA (Verband der Automotilindustrie). It was conducted as a test with two different types of seat trim cover (knit) and plastics (PC+ABS) applied at arm rest in automotive interior. Through the principle test, the knit were more advantageous for squeak noise than other fabrics around relative part of seat particularly with suede, tricot and PC+ABS. We also optimized the concentration of soft agent in knit for slipping through stick-slip test to moderate noise. The concentration of soft agent is about 5% that squeak noise was below 3 for all case of plastic and seat covering. If the concentration of soft agent in knit is more or less than 5%, a fabric is excessively contracted or changed into different characteristics. Additionally, dense system of knit can decrease noise compare to loose organization. Based on these results, we developed an improved knit for squeak noise to apply of meeting parts at seat. This fabric can prevent the squeak noise even though abrasion and environmental conditions. The result of this study could be used to decrease in noise and be useful for selection of the materials at seat and relative parts.
Choi, Hyerin, Song, Junho, Jeong, Kie Youn
Evaluation of Lumbar-Load Criterion Based on Test Data and Field Performance Results of the UH-60 Black Hawk Crew SeatF-0074-2018-127395/14/2018
ABSTRACT The BAE Systems legacy UH-60A/L Black Hawk Crew Seat has been in serial production for almost 40 years, and has garnered a reputation for providing a high degree of crash safety to its occupants. The seat has been dynamically tested over 150 times, providing a wealth of test data that are summarized in this paper. This paper also presents a review of data from actual UH-60A/L crashes that verifies the seat's excellent performance with regards to minimizing occupant compressive spinal injuries. In addition, this paper presents a compilation of test data containing ATD lumbar-load readings. The dynamic test results are then compared to the lumbar-load limits specified in JSSG-2010-7 and the more recent Full Spectrum Crashworthiness (FSC) Criteria for Rotorcraft. This comparison shows that the seat most likely would not have passed the FSC criteria, which indicates that either the FSC lumbar-load limits are set too low, or that the dynamic test pulses do not replicate the actual crash environment. The JSSG criteria were found to be a better predictor of the seat's actual crash performance.
Richards, Marvin
The Evaluation of Anthropomorphic Test Device Response under Vertical LoadingF-0074-2018-127385/14/2018
ABSTRACT During the winter of 2018, a series of vertical tests was conducted on three sizes of Anthropomorphic Test Devices (ATDs) for the evaluation of their vertical loading response. The three sizes of ATDs represented a 5th percentile female, a 50th percentile male, and a 95th percentile male. There were two variations of the 50th percentile male as defined in 49 CFR Part 572: a Hybrid II and an FAA Hybrid III. Tests were conducted on a drop tower located at NASA Langley Research Center's (LaRC) Landing and Impact Research (LandIR) Facility. The ATDs were seated on 14 CFR § 25.562 certified seats, in either a triple (window, middle and aisle) or a double (window and aisle) seat configuration, with seat leg spacing replicating a Fokker F28 MK-1000 aircraft. The seat and ATDs were attached to a drop plate on the tower, which was lifted to a height of 14 ft. The system was dropped onto different sections of crushable foam wedges to achieve multiple input deceleration environments. The purpose of the tests was to evaluate the differences in lumbar response, to examine scaling characteristics from sizing factors in the ATDs, and also to compare the results to computer simulation efforts. Results will be presented and comparisons will be discussed.
Littell, Justin, Annett, Martin
Evaluation Method of Thermal Sensation and Comfort for Air Conditioning Performance Reduction2018-01-07754/3/2018
As a method of maintaining thermal sensation and comfort inside a passenger compartment, not only a conventional HVAC system but also a combination of a HVAC system and other devices such as seat heaters, a steering wheel heater, ventilation seats are increasing. This research developed a method to evaluate thermal sensation of a human body when using these various thermal control devices. This method can evaluate the heat balance of the human body by calculating the amount of heat exchange between a human body and the external environment, and it takes into consideration the influence of heat exchange by heat conduction with seats or a steering wheel. The human thermal model is made by dividing a human body into various segments, and it is the model that considers heat transport by blood flow for each segment. As a result of a heat balance of a human body, it is possible to derive the standard environmental temperature which is named the local-body standard new effective temperature (local SET*) for each part of a human body. Local thermal sensation is defined by a model equation that takes into consideration transient changes of a heat balance and an influence of heat storage by a whole body. Therefore, it is possible to evaluate thermal comfort of occupants in a vehicle cabin in transient and non-uniform situation. The authors conducted the experiment using actual vehicles and evaluated how much thermal sensation changes when an air conditioning system is different, using this evaluation method. Energy measurements for maintaining vehicle cabin environment and thermal sensation in the vehicle cabin were simultaneously carried out and the results of thermal sensation evaluation were shown.
ITO, Yusuke, Sakoi, Tomonori, Miyamoto, Takeshi
Automotive Thermal Environment Model to Design Climate Control Logics Based on Thermal Sensation2018-01-00644/3/2018
This paper describes newly developed model-in-the-loop simulation (MILS) which makes design for cooperative climate control logics between automotive HVAC (heating, ventilation and air conditioner) and auxiliary thermal devices more efficient in considering thermal sensation and comfort of occupants. The auxiliary thermal devices such as an air-conditioned seat and a heated steering wheel consume less energy than the HVAC, and they have a potential to improve the total energy consumption satisfying thermal comfort of occupants. However, it is not easy to design the cooperative climate control logics for these thermal devices since thermal sensation and comfort must be taken into account while the logic optimization. The proposed MILS consists of thermal-environment model, thermal-device model, ambient conditions and climate control logics. The thermal-environment model simulates dynamics of temperature distribution in a cabin and human body. Compartment model is adopted for the thermal environment model, and it provides higher-speed simulations than distributed parameter model. Thermal sensation and comfort of occupants are computed on the basis of heat loss of occupants. Local thermal sensation of occupants are estimated by equivalent temperature (Teq), and we confirmed that Teq had a linear correlation to declared values of subjects. UC Berkeley’s comfort model is used to convert local sensation to overall sensation and comfort. An HVAC, an air-conditioned seat and a heated steering wheel are modeled with experimental results, and the thermal-device models are controlled by the climate control logics. Model validation has been conducted by comparison with the experimental results. In consequence, the results of temperature and thermal sensation in simulation correspond with the experiments. Therefore we can study the effectiveness of prototyped cooperative climate control logics referring to thermal comfort and energy consumption by using the outputs of this MILS before actual vehicle tests.
Kubota, Takuya, Ishikawa, Takayuki, Tosaka, Jun, Okayasu, Hidetoshi
Optimization of Center Console Duct Using Robust Assessment Methodology2018-01-00724/3/2018
The thermal comfort for the passenger inside the cabin is maintained by the HVAC system. To ensure a comfort for the 2nd row passengers in the cabin, it is very essential to design an efficient HVAC and rear console duct system which can deliver sufficient airflow with less pressure drop. The primary focus of the study is to assess existing airflow of the center console duct using CFD and propose improvement in its duct shape to meet the passenger comfort sitting in the rear seat. In this study, the vehicle cabin model, HVAC system and duct design was modeled using the design software UG. To analyze and estimate the behavior of the air flow of the system, a steady state simulation was performed using STAR CCM CFD software. The performance of the console duct system is judged by parameters like distribution of airflow, velocity at console duct outlet, pressure drop through the duct and the uniformity of the air flow at the passenger locations. Robust assessment methodology is followed for optimization of console duct to reduce the simulation iterations and arrive at the combination of appropriate design factors which influences the airflow, pressure drop within the duct and velocity at second row passenger locations within the short span of time. The impacts of each design factors on the output results have been analyzed extensively and best combination of design factors have been found out quickly through this methodology. Robust assessment methodology significantly aids in reducing the CFD simulation iterations by 40% and much faster than conventional optimization process. Vehicle testing was carried out for the existing and optimized console duct design to measure the improvement in airflow and velocity at passenger locations. There is a good correlation agreement between simulation and test results for the optimized design within the error of 10%. This methodology is very useful in reducing the number of prototypes, minimize the testing cost and reduce the simulation iterations during design and development stages of the program.
Vasanth, B., Khan, Mohsin, S, Sathish Kumar, Garikipati, Nagababu, NARAYANA, Sathya, Govindarajalu, Murali
CAE Methodology for Seat Assessment with H-Point Machine2018-01-13224/3/2018
Seat assessment is an important necessity for the growing auto industry. The design of seats is driven by customer’s demand of comfort and aesthetics of the vehicle interiors. Some of the few seat assessments are H-point prediction with H-point Machine (HPM); backset prediction with Head Restraint Measuring Device (HRMD); seat hardness and softness. Traditional seat development was through developing series of prototypes to meet requirements which involved higher costs and more time. The seat requirement of H-Point measurement is of focus in this paper. Though there are other commercial available software/methods to perform the H-point measurement simulations, the aim here was to assess the capabilities of an alternate Computer Aided Engineering (CAE) methodology using CAE tools - PRIMER and LS-Dyna. The pre-processing tools - Hypermesh and ANSA have been used for modeling and Hyperview tool used for reviewing the simulations. The CAE results show good correlation to test results and compare well to other commercial software/methods. This methodology has been beneficial in developing seat designs in the early development cycle much before the final prototype testing.
Manjunath, Vinay, Tuniki, Raju, Kamalakkannan, Sarath Babu, Mathur, Mohit, Kolich, Michael
Simulation Driven Optimization of Automotive Floor Console Mounting Brackets – An Overview2018-01-10204/3/2018
Floor consoles or Center consoles are an indispensable part of Automotive Cockpit systems in modern passenger vehicles. It occupies space between the front seats in the car and has a lot of utilities and functionalities. The center console design can be very simple as just providing an enclosure for the gear shifter and parking brake and as complex as having storage bins with armrest which can slide. Now-a-days a lot of functionalities are being provided by the center console such as housing the AC vents at the rear, provision for USB and power outlets etc. All these utilities within the center console demand a certain amount of structural rigidity to meet the functional requirements as well as applicable regulatory requirements. The console mounting bracket usually serves to attach the plastic center console to the steel underbody. It also acts as a load carrier for the console and its design influences the overall stiffness and modal characteristics of the console system. In this paper, two different CAE optimization strategies are applied to two variants of console for a passenger minivan application. For one console model, topology optimization strategy is applied to optimize the material on its mounting bracket. In the other console model, which is relatively complex, topography optimization strategy is applied to its mounting bracket for meeting the functional requirements of the console assembly. The critical functional requirements are validated through CAE techniques and correlation with physical test for one of the variants is highlighted in this paper.
Taruvai Sankaran, Raghuraman, S, Arunkumar, Arunachalam, Muthukumar, Gudla, harinadh
The Seat Interference Potential as an Indicator for the Aircraft Boarding Progress2017-01-21139/19/2017
Passenger boarding is always part of the critical path of the aircraft turnaround: both efficient boarding and online prediction of the boarding progress are essential for a reliable turnaround progress. However, the boarding progress is mainly controlled by the passenger behavior. A fundamental scientific approach for aircraft boarding enables the consideration of individual passenger behaviors and operational constraints in order to develop a sustainable concept for enabling a prediction of the boarding progress. A reliable microscopic simulation approach is used to model the passenger behavior, where the individual movement is defined as a one-dimensional, stochastic, and time/space discrete transition process. The simulation covers a broad range of behaviors and boarding strategies as well as the integration of new technologies and procedures. Future cabin management systems will provide an enabling infrastructure to further improve the overall turnaround process and to allow for on-line prediction of specific handling processes. The paper provides a method to indicate the progress of the aircraft boarding. In this context, the aircraft seats are used as a sensor network with the capability to detect the status (free or occupied) of each seat. These individual seat statuses are used to derive an aggregated interference potential of the current seating condition with regards to the passenger seating process. The interference potential is a major indicator for the expected aircraft boarding time. In combination with an integrated airline/airport information management (e.g. sequence of boarding passengers) the boarding progress will be transformed from a black box to a transparent progress with the operator’s online ability to react to significant deviations from the planned progress.
Schultz, Michael
Potential Effects of Deceleration Pulse Variations on Injury Measures Computed in Aircraft Seat HIC Analysis Testing2017-01-20529/19/2017
Aircraft seating systems are evaluated utilizing a variety of impact conditions and selected injury measures. Injury measures like the Head Injury Criterion (HIC) are evaluated under standardized conditions using anthropomorphic dummies such as those outlined in 14 CFR part 25. An example test involves decelerating one or more rows of seats and allowing a lap-belted dummy to impact components in front of it, which typically include the seatback and its integrated features. Examples of head contact surfaces include video monitors, a wide range of seat back materials, and airbags. The HIC, and other injury measures such as Nij, can be calculated during such impacts. A minimum test pulse, with minimum allowable acceleration vs time boundaries, is defined as part of the regulations for a frontal impact. In this study the effects of variations in decelerations that meet the requirements are considered. A series of Finite Element simulations of a generalized aircraft seat were performed to determine the variation in HIC and Nij observed based on variations in the deceleration pulse. The results indicate that the pulse characteristics affect the resulting head motions and can influence the ability to pass the HIC analysis test.
Friedman, K, Mattos, G, Bui, K, Hutchinson, J, Jafri, A, Paver PhD, J
Reusable Sponge Absorbs Oil from Entire Water ColumnTBMG-272027/1/2017
When the Deepwater Horizon drilling pipe blew out seven years ago, beginning the worst oil spill in U.S. history, those in charge of the recovery discovered that the millions of gallons of oil bubbling from the sea floor weren’t all collecting on the surface where it could be skimmed or burned. Some of it was forming a plume and drifting under the surface of the ocean.
Comparing the Whole Body Vibration Exposures across Three Truck Seats2017-01-18366/5/2017
Whole-body vibration (WBV) is associated with several adverse health and safety outcomes including low-back pain (LBP) and driver fatigue. The objective of this study was to evaluate the efficacy of three commercially-available air-suspension truck seats for reducing truck drivers’ exposures to WBV. Seventeen truck drivers operating over a standardized route were recruited for this study and three commercially-available air suspension seats were evaluated. The predominant, z-axis average weighted vibration (Aw) and Vibration Dose Values (VDV) were calculated and normalized to represent eight hours of truck operation. In addition, the Seat Effective Amplitude Transmissibility (SEAT), the ratio of the seat-measured vibration divided by the floor-measured vibration, was compared across the three seats. One seat had significantly higher on-road WBV exposures whereas there were no differences across seats in off-road WBV exposures. The SEAT values, calculated over the whole route (which was predominantly on-road) indicated that one seat reduced WBV exposure by 9% on average and the other two seats had nearly double the attenuation performance based on A(8) exposures. The performance differences across seats may have important practical implications for truck procurement and overall truck driver health. The higher performing seats nearly doubled the amount of time drivers could operate their trucks before reaching the daily vibration action limits recommended by the International Organization for Standardization. Seat suspension-based design differences are thought to account for the performance differences.
Wang, Fangfang, Johnson, Peter, Davies, Hugh, Du, Bronson
Truck and Construction Seat BSR Identification and Characterization2017-01-18586/5/2017
Truck and construction seats offer a number of different challenges compared to automotive seats in the identification and characterization of Buzz, Squeak, and Rattle (BSR) noises. These seats typically have a separate air or mechanical suspension and usually a larger number and variety of mechanical adjustments and isolators. Associated vibration excitation tend to have lower frequencies with larger amplitudes. In order to test these seats for both BSR and vibration isolation a low-noise shaker with the ability to test to a minimum frequency of 1 Hz was employed. Slowly swept sine excitation was used to visualize the seat mode shapes and identify nonlinearities at low frequencies. A sample set of seat BSR sounds are described in terms of time and frequency characteristics, then analyzed using sound quality metrics.
Haylett, James, Polte, Andrew
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
Evaluation of Aircrew Whole-Body Vibration and Mitigation Solutions for Helicopter Flight EngineersF-0073-2017-120415/9/2017
ABSTRACT Flight testing has been performed on a Bell-205 helicopter to investigate aircrew whole-body vibration (WBV) exposure levels on a rag and tube Flight Engineer (FE) seat in accordance with ISO2631 and MIL-STD1472 standards. Results show that the helicopter cabin vibration is dominated by the N/rev harmonics of the two-bladed main rotor speed. The aircrew WBV levels vary significantly depending on the flight conditions; the highest WBV levels occur at high speed level flight conditions. With reference to the ISO2631 and MIL-STD-1472 guidelines, the aircrew WBV exposure level on the standard FE seat in the entire tested flight profile is qualitatively rated as "uncomfortable". Limiting the maximum duration of such missions to 1 hour would ensure compliance with the limit of ISO2631 vibration health and risk guideline "Caution Zone". It is also noted that the use of gunner seat insert cushion for combat missions can lead to a significant increase in the aircrew WBV levels. However, the use of selected carry-on cushion pads can provide an effective WBV mitigation to the aircrew in the majority of flight conditions. Further occupant WBV tests on a human rated mechanical shaker table also verified that selected carryon seat cushion pads are also effective in the mitigation of occupant WBV levels on the Bell-412 helicopter.
Chen, Yong, Yapa, Upekha, Price, Andrew, Wickramasinghe, Viresh
New York auto show: Lincoln unveils all-new, aluminum-bodied 2018 Navigator17AUTP05_135/1/2017
Ford's Lincoln luxury-vehicle unit revealed the 2018 Navigator fullsize SUV at the 2017 New York auto show by touting its blend of smart basic engineering and smart features. Like the recently-revealed Ford Expedition, its Lincoln counterpart is fitted with weight-saving aluminum bodywork to cut roughly 200 lb (91 kg) from the curb weight and help offset the mass of the new Navigator's copious luxury and advanced driver-assist features.
Visnic, Bill
A Study of the Effect of Air-Mat Seat Pressure Level on Seating Comfort2017-01-13953/28/2017
Seat cushions are considered as one of the important factors influence the seating comfort. In the automotive seat cushions, flexible polyurethane foams have been widely used due to the cushioning performance. Automotive seat designers are paying more attention to the improvement of seat cushion properties. This study introduces an automotive seat that uses an air-mat in the seat cushion along with polyurethane foam. The air-mat can be adjusted with its internal air pressure. The objective of this paper is to examine air-mat seat pressure level on seating comfort. Vibration experiments have been performed on the BSR simulator with random vibration. Tri-axial accelerometers were used to measure vibration at the foot and hip. All measured vibration were about the vertical direction (z-axis). The whole-body vibration exposure parameters (weighted root-mean-square (RMS), vibration dose value (VDV), transmissibility (SEAT value)) were calculated per ISO 2631-1 standard. The air-mat internal air pressures considered were 0.017, 0.035, 0.053, and 0.07 MPa. Twelve healthy individuals who had more than ten years of driving experience participated. The participants were grouped into four weight groups were ~45 kg, 60-70 kg, 70-80 kg, and 90-100 kg. Results showed that weighted RMS, VDV, and SEAT value decreased with increased internal air pressure level for 45 kg weight group. However, a different trend of results observed for other weight groups. The possible explanation could be hip muscle characteristics includes muscle thickness, muscle strength, fat (i.e., damping effect). This paper will discuss the seat development, seating comfort evaluation method, results, and suggestions.
Park, Se Jin, Subramaniyam, Murali, Hong, Seunghee, Kim, Damee, Kim, Tae Hyun, Cho, Dong Woo, Shim, Bum Il
Investigation of a Dual HVAC MAC System with Three Row Ducts Using 1D Modeling2017-01-01643/28/2017
In an automotive air-conditioning (AC) system, upfront prediction of the cabin cool down rate in the initial design stage will help in reducing the overall product development (PD) time. Vehicle having higher seating capacity will have higher thermal load and providing thermal comfort to all passengers uniformly is a challenging task for the automotive HVAC (Heating Ventilation and Air conditioning) industry. Dual HVAC unit is generally used to provide uniform cooling to a large cabin volume. One dimensional (1D) simulation is being extensively used to predict the HVAC performance during the initial stage of PD. The refrigerant loop with components such as compressor, condenser, TXV and evaporator was modeled. The complicated vehicle cabin including the glazing surfaces and enclosures were modeled as a three row duct system using 1D tool AMESim®. The material type, density, specific heat capacity and thermal conductivity of the material were specified. The actual vehicle driving conditions as per test standard were used to validate the transient 1D HVAC performance simulations. The heat gain values of the panel ducts were adjusted to reduce the deviation from test. The simulated results for average cabin temperature and grill outlet temperature were compared against a surrogate vehicle test data. The detailed comparison of test data and simulation results were plotted and identified the simulation parameter which affects the correlation. Studies were carried out to understand the influence of thermal parameters on the performance of dual HVAC system and optimal values were arrived for the system under study.
Muthusamy, Venkatesan, Sathish Kumar, S., Sambandan, Saravanan
Optimum Seat Cooling Distribution for Targeted Human Thermal Comfort®2017-01-01703/28/2017
Seat cooling and heating strategies have enhanced human thermal comfort in automotive environments. Cooling/heating strategies also need to focus on the distribution of the seat cooling/heating power across the seat and the effect of such distributions on human thermal comfort. This paper studies the effect of active cooling combined with ventilation only strategy on thermal comfort. As part of the study, heat flux between the occupant and seat is mapped and is correlated to a step increase in the occupant’s local thermal comfort of body segments in contact with seat. A human physiological model and the Berkeley comfort model were combined to determine power and optimum placement of cooling to effectively cool an occupant using a climate control seat in a warm environment. This leads to a new approach using asymmetric seat cooling to distribute cooling power resulting in improved and balanced subjective comfort than traditional climate seat and ventilation technologies. A computational model was developed and validated through chamber test results. The computational model can deliver temperature distribution and thermal sensation/comfort values for varied boundary conditions such as differing ambient temperatures, mass flow rates and temperatures of cooling air through seat. In this study, the thermal chamber and seat were soaked to 44oC before running the test with the human seated. Active cooling was applied to seat back/lumbar area and ventilation only was applied to the seat cushion area. The occupants recorded their local contact segment sensation and comfort every two minutes. Temperatures for the seat and human as well as heat flux between them were measured every 1 second. The model temperatures correlated to within 1oC of experiment. The computed local thermal sensation and comfort values were also correlated to those measured in the chamber.
Velivelli, Aditya, Guerithault, Daniel, Stöwe, Stefan
I.D. Buzz: VW's latest future-look Microbus17AUTP02_142/1/2017
It's a VW Microbus for future generations, an electric van capable of fully autonomous driving. But at this point, it's only a concept. “We want to re-ignite America's love for Volkswagen. And we are fully committed to the future of mobility-smart, sustainable, affordable-that is the new Volkswagen,” proclaimed Dr. Herbert Diess, Chairman of the Board of Management for the Volkswagen Brand.
Buchholz, Kami
Airbus brings four dimensions to Airspace16MEIP06_136/1/2016
As Airbus looks to launch new-engine option (neo) aircraft, it has announced it is also launching a new cabin brand it calls “Airspace by Airbus.” In essence, Airbus is hoping that its Airspace will enhance the passenger experience just as the new engines will enhance the airlines' bottom line due to efficiency increases. Culminating in what Airbus describes as “the best of [its] cabin innovation and design,” Airspace offers “a flexible canvas as a back-drop to enhance the airlines' own brands.” The new cabin is being touted as offering a more relaxing and functional environment for the passenger while optimizing space utilization. It will be launched with the A330neo wide-body airliner, which is inspired by the cabin of its in-service sibling, the A350 XWB.
Broge, Jean L.
Assessment of Memory Cushions in Aircraft Seating for Injury Mitigation through Dynamic Impact TestF-0072-2016-114115/17/2016
Dynamic impact tests were conducted to assess the effectiveness of the Visco-Elastic Polyurethane (VEPU) memory foam seat cushions in mitigating impact to the occupant during an aircraft crash. A FAA specification Hybrid III crash dummy and seats with and without a stroke energy absorbing mechanism were used in the tests. Polyurethane foam (PU) cushions were also tested for comparison. The results with the rigid seat indicated that with 8.3 m/s impact, lumbar spine injury would occur. VEPU cushions reduced the lumbar force by up to 34%. With an impact speed of 6m/s, a VEPU cushion mitigated the impact to the tolerable level, whilst injury would still occur with the PU cushions. The results with the energy absorbing seats showed that with 8.3 m/s impact speed, the seat with over 125 mm (5 inch) stroke length is able to reduce the impact load below the injury threshold. A relatively softer VEPU cushion reduced the lumbar force by over 15% compared with the PU cushions. With a stoke length of 75 mm (3 inch), bottom-out occurred and occupant lumbar spine injury would occur. A relatively higher stiffness VEPU cushion reduced lumbar force by around 20%.
Wang, John, Nevo, Ross
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
Next Generation Smart Crashworthy Crew SeatsF-0072-2016-114155/17/2016
The next generation smart crashworthy crew seats will need to include design features that provide an enhanced level of crash safety while reducing the crew discomfort during long military missions. This paper presents the results from the Active Crash Protection Systems Enhancements II Program jointly funded by the U.S. Army Aviation Development Directorate - Aviation Applied Technology Directorate (ADD-AATD) and The Boeing Company under a Technology Investment Agreement. During this program a prototype crew seat design concept with actively-controlled seat energy absorbers was developed and integrated with an aircraft active crash protection system. The actively-controlled seat energy absorber technology developed enables automatic adjustment of the stroking load of the energy absorbers based on the occupant weight, available seat stroke, and the predicted crash impact conditions in order to provide an increased level of crash safety to the crew. The paper also includes results and recommendations from a crew seat ergonomic design study conducted to reduce crew discomfort during long missions.
Bolukbasi, Akif
Transport Aircraft Seating in Rotorcraft Crash TestingF-0072-2016-114125/17/2016
The Federal Aviation Administration (FAA) has standards and regulations that are designed to protect aircraft occupants in the event of a crash. These standards focus primarily on horizontal and vertical impact protection, and measure the dynamic performance of the seating system and occupant restraints. Currently no requirement for full-scale crashworthiness testing exists due to the cost prohibitive nature of conducting such a test. The requirements were developed through review of research, existing requirements, modeling and simulation, and accident analysis. A drop of a Transport Rotorcraft Airframe Crash Testbed (TRACT), CH-46 airframe, at the National Aeronautics and Space Agency's Langley Research Center Landing and Impact Facility, provided an opportunity to investigate the performance of an airframe in a simulated crash condition. This provided full scale data on the performance of previously approved transport category aircraft seating systems. Passenger seats that were previously certified to 14 CFR § 25.562 aviation regulations with a 49 CFR § 572 50% Hybrid II Anthropomorphic Test Device (ATD) were included in the testing. It was expected that the real crash pulse measured at the floor, would differ from the certification tests and the performance of the seats would as well. The ATDs used in the crash test included the 50% Hybrid II, a 50% FAA Hybrid III, 5% Hybrid III and a 95% Hybrid III. Injuries in the spinal column are of concern, so lumbar loads were collected for all ATDs, in addition to head, chest and pelvis accelerations. The Part 25 Passenger seats remained attached to the floor structure; however the experimental sub floor structure failed for the forward occupants. The restraint system held the occupants in place, however the compressive lumbar loads measured were significantly higher than those seen in typical certification tests, and exceeded the regulatory limit of 1500 lb. Typical certification tests primarily use the 50% Hybrid II or an equivalent, which is the FAA Hybrid III. The main performance requirement during a vertical test is the compressive lumbar loads, but structural integrity is also evaluated. This testing demonstrated that seats dynamically qualified for lower impact severities (14 G) were able to maintain structural integrity but were not able to control spinal injury risk at this load level.
Pellettiere, Joseph, Taylor, Amanda
A Sectoral Approach to Modelling Wall Heat Transfer in Exhaust Ports and Manifolds for Turbocharged Gasoline Engines2016-01-02024/5/2016
A new approach is presented to modelling wall heat transfer in the exhaust port and manifold within 1D gas exchange simulation to ensure a precise calculation of thermal exhaust enthalpy. One of the principal characteristics of this approach is the partition of the exhaust process in a blow-down and a push-out phase. In addition to the split in two phases, the exhaust system is divided into several sections to consider changes in heat transfer characteristics downstream the exhaust valves. Principally, the convective heat transfer is described by the characteristic numbers of Nusselt, Reynolds and Prandtl. However, the phase individual correlation coefficients are derived from 3D CFD investigations of the flow in the exhaust system combined with Low-Re turbulence modelling. Furthermore, heat losses on the valve and the seat ring surfaces are considered by an empirical model approach. Since the comparison between measured and simulated exhaust temperature at turbine inlet serves as an evaluation criterion, a detailed 1D thermocouple model is implemented. Exothermic exhaust after-reactions are represented by a reduced reaction kinetics mechanism. The investigations were carried out for four TC-DI gasoline engines. The low scattering of the correlation coefficients as well as the high agreement between simulated and measured exhaust temperature verify the model quality. Overall, the new sectoral approach shows a significant improvement of wall heat flux calculation in comparison to conventional single-phase approaches from literature.
Franzke, Bjoern, Pischinger, Stefan, Adomeit, Philipp, Schernus, Christof, Scharf, Johannes, Uhlmann, Tolga
Evaluation of the Seat Index Point Tool for Military Seats2016-01-03094/5/2016
This study evaluated the ISO 5353 Seat Index Point Tool (SIPT) as an alternative to the SAE J826 H-point manikin for measuring military seats. A tool was fabricated based on the ISO specification and a custom back-angle measurement probe was designed and fitted to the SIPT. Comparisons between the two tools in a wide range of seating conditions showed that the mean SIP location was 5 mm aft of the H-point, with a standard deviation of 7.8 mm. Vertical location was not significantly different between the two tools (mean - 0.7 mm, sd 4.0 mm). A high correlation (r=0.9) was observed between the back angle measurements from the two tools. The SIPT was slightly more repeatable across installations and installers than the J826 manikin, with most of the discrepancy arising from situations with flat seat cushion angles and either unusually upright or reclined back angles that caused the J826 manikin to be unstable. The investigators who performed the measurements indicated that the SIPT was easier to use. The data show that the SIPT is a reasonable substitute for the SAE J826 manikin when ease-of-use considerations favor the SIPT, such as restricted space around the seat, low seat heights, or low cushion angles. Human posture measurements in seats with large discrepancies between the tools will be needed to determine which provides a better prediction of sitter position.
Reed, Matthew, Ebert-Hamilton, Sheila
Tactile Sensor Array Design for Triple Seat Detection and Control2016-28-02582/1/2016
In the field of automotive if a vehicle is designed for a particular per person riding capacity considering the aspects of safety, design and power exceeding those limits puts the driver and pillion riders at considerable risk. With a step ahead in this paper we are trying to detect and limit the number of persons sitting on two wheeler. As per the traffic rules in India the maximum number of persons cannot exceed two, apart from the driver only one pillion rider can be carried in behind while driving. Despite of the ban, driver carries more than a single person. Two Pillion riding is also a root of a lot of accidents happening in two wheelers. To make the detection process effective, robust and cost effective a new sensor design was to be put forward. There is no sensor available that could detect the differential load over the larger area at effective cost. To cater to this problem Bubble based tactile based sensors were developed and checked for this application. An array of Bubble based Tactile sensors are placed on the seat that are most likely to encounter weights during multiple pillion riding, as per the number of persons seated the state of the switches will be read and monitored by a small Control Unit(microcontroller). The mechanism to detect the number of seater’s is done by detecting the concentration points, an algorithm is implemented that will detect a valid occupant on the seat. After the detection of overloading of the persons on the bike the Control unit can disable the engine or set a warning light. So far no such device is made to tackle such situations and this innovation can prove a viable option to reduce triple seat driving in two wheelers.
Bashir, Eeshan, Patil, Sanjay A
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