Browse Topic: Child injuries

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Far Side Impact Injury Threshold Recommendations Based on 6 Paired WorldSID / Post Mortem Human Subjects Tests2019-22-00053/31/2020
Far side has been identified in the literature as a potential cause of numerous injuries and fatalities. Euro NCAP developed a far side test protocol to be performed to assess adult protection. A monitoring phase was undertaken between January 2018 and December 2019, and the far side assessment will become part of the rating for all vehicles launched in 2020 onward. A test buck was developed and 6 paired WorldSID / Post Mortem Human Subjects (PMHS) were subjected to the test protocol proposed by Euro NCAP to contribute to the development of limits. The buck consisted of a rigid seat and a rigid central console covered with 50 mm of Ethafoam TM 180 with a density of 16 kg/m3. The buck was mounted on the sled with an angle of 75° between the X axis of the vehicle and the X axis of the sled. The peak head excursion was compared between PMHS and the WorldSID dummy. It was found reasonably similar. However, the dummy repeatability was found to be poor. Out of 6 tests conducted on 6 PMHS, 2 specimens sustained AIS3 and, 3 specimens AIS2 cervical spine injuries, 3 specimens sustained AIS3, 1 AIS2 and 1 AIS1 thoracic injuries, and 2 specimens sustained AIS2 abdominal injuries. The peak values recorded on the dummy according to the Euro NCAP protocol were compared with the injury assessments of the PMHS tests. In the configuration used, which includes a central console, the hard thorax injury prediction was found to be excellent. For the neck injury prediction, the data were merged with similar results available in the literature and an Injury Risk Curve was proposed as a derivative from the curve published by Mertz et al. (2003) for neck extension.
Petit, Philippe, Trosseille, Xavier, Uriot, Jérome, Poulard, David, Potier, Pascal, Baudrit, Pascal, Compigne, Sabine, Kunisada, Masato, Tsurui, Kenji
Comparative protocol study between R44 and I-Size regulations for child restraint systems2018-36-01249/3/2018
Children tend to be victims of road accidents more often than is the case for adults. Children made up 2,5% of the total number of road fatalities in the EU countries in 2015 and about 15% of the world? population. They are at about a sixth regarding the risk of dying in a road accident of the average member of the population across the EU as a whole.[1] The European Union uses the R44.04 [2] homologation standard to assess child restraint systems (CRS), but in 2013 a new regulation was implemented called Enhanced Child Restraint Systems (ECRS) or UNECE R-129[3] The first step of this regulation, called Phase 1 or I-Size, adds new performance criterion and improved the requirements for the CRS related to safety by introducing side-impact protection, classification based on stature not mass, use of Isofix and mandatory rearward facing until 15 months. Both regulations have been used simultaneously since 2013. In this paper a comparison study was carried out to analyse the differences between both protocols and regulation requirements in order to assess the benefits and impacts of this new standard.
Domenech, David, Parera, Nuria, Maturana, Gustavo
Estimation of Injury Risk of the Cervical Spine of Car Occupants after Emergency Braking2018-01-05414/3/2018
This study deals with the question whether or not a “braking with maximum deceleration” represents a specific physical load situation for the occupants of a car. For this purpose, a literature study was performed to determine the relevance of symptoms concerning whiplash-associated disorders (WAD) of car occupants who were involved in traffic accidents with low accident severity. Additionally, test drives with full braking cars were conducted to determine the load situation of the neck for human test persons. Dummies were used too, which were equipped with measuring components at the head and thorax to identify the effective acceleration/deceleration and to compare these values to scientific approved characteristic deceleration values and to the existing neck injury criteria. Finally, the likelihood of occurrence of symptoms in terms of a neck injury was evaluated from the medical and biomechanical point of view. The study shows that there is basically no risk for the occurrence of neck injuries and neck pain (whiplash disorders) for car occupants who experienced a full braking maneuver. This applies for the specific individual measured data of the test subjects compared to the known maximum load from the literature. But the authors of the study have to point out that special individual psychological and physiological frame conditions can lead to symptoms in terms of minor whiplash associated disorders like muscle tension symptoms.
Otte, Dietmar, Facius lng, Thorsten, Johannsen, Heiko, Hüfner, Tobias
A Comparative Study of Vehicle Front Shape Based on Multi-Objective Optimization for Minimizing Injury Risks in Pedestrian and Cyclist Impact2018-01-10464/3/2018
This study aims to explore the influence of a vehicle front-end shape on pedestrian and cyclist injuries. The injuries of head, upper leg and lower leg based on 50th human model are considered as design response. A multi-objective optimization approach is developed to design and optimize the front shape for minimizing injury risks of pedestrian and cyclist in this study. The numerical models of pedestrian-vehicle and cyclist-vehicle impact is constructed and validated first. Then, the optimal Latin hypercube sampling (OLHS) method is adopted for design of experiment (DOE) and the surrogate model is constructed through radial basis function (RBF). The optimal problems involving a number of objectives are solved by the multi-objective particle swarm optimization (MOPSO) algorithm in this study. With the optimization design of vehicle front shape by using pedestrian-vehicle impact and cyclist-vehicle impact, the optimal front shape is obtained although some design variables strongly compete with each other.
Lv, Xiaojiang, Liu, Weiguo, Zhou, Dayong, Zhang, Haiyang, Gu, Xianguang
Regional Level Crash Induced Injury Metrics Implemented within THUMS v4.012016-01-14894/5/2016
Crash reconstructions using finite element (FE) vehicle and human body models (HBMs) allow researchers to investigate injury mechanisms, predict injury risk, and evaluate the effectiveness of injury mitigation systems, ultimately leading to a reduced risk of fatal and severe injury in motor vehicle crashes (MVCs). To predict injuries, regional-level injury metrics were implemented into the Total Human Model for Safety (THUMS) full body HBM. THUMS was virtually instrumented with cross-sectional planes to measure forces and moments in the femurs, upper and lower tibias, ankles, pelvis (pubic symphysis, ilium, ischium, sacrum, ischial tuberosity, and inferior and superior pubic ramus), and the cervical, thoracic, and lumbar vertebrae and intervertebral discs. To measure accelerations, virtual accelerometers were implemented in the head, thoracic vertebrae, sternum, ribs, and pelvis. Three chest bands and an abdominal band were implemented to measure chest and abdominal deflection. Organ injury is assessed with volumetric strain-based metrics in the lung, liver, and spleen. The kinematic and kinetic data described were batch-processed using a custom-built program known as the Injury Prediction Post-Processor (IPPP) to evaluate common injury metrics and risk probabilities from literature. A total of 30 injury metrics are currently implemented in the IPPP, including Head Injury Criterion (HIC), Combined Thoracic Index (CTI), and cross-sectional forces and moments. We have observed improved ability and accuracy in predicting real-world injury using stress and strain analysis compared to traditionally employed criteria for anthropomorphic test devices (ATDs).
Miller, Logan, Gaewsky, James, Weaver, Ashley, Stitzel, Joel, White, Nicholas
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
Lightweight Seat Design and Crash Simulations2015-01-14724/14/2015
The lightweight seat of a high performance car is designed taking into account a rear impact, i.e. the crash due to an impulse applied from the rear. The basic parameters of the seat structure are derived resorting to simulations of a crash with a test dummy positioned on the seat. The simulations provide the forces acting at the seat structure, in particular the forces applied at the joint between the seat cushion and the seat backrest are taken into account. Such a joint is simulated as a plastic hinge and dissipates some of the crash energy. The simulations are validated by means of indoor tests with satisfactory results. A tool has been developed for the preliminary design of lightweight seats for high performance cars.
Arienti, Roberto, Cantoni, Carlo, Gobbi, Massimiliano, Mastinu, Giampiero, Pennati, Mario, Previati, Giorgio
Traffic Accidents of Children Passengers Travelling in Powered Two Wheels Vehicles2014-36-02479/30/2014
According to the “Report 2010” of the Association des Constructeurs Européens de Motocycles (European motorcycle manufacturers' association), the number of motorcycles throughout the European Union rose from 16 million to more than 22 million between 2001 and 2008. Taking all two-wheeled motor vehicles into account, in 2008 approximately 33 million vehicles were registered. At the same time, motorcycles are by far the most dangerous means of transport. Two groups (children and elderly people) are especially vulnerable due to their weakness against impact, reflexes and reaction to risk, resistance to the generated forces, etc. According to the latest accidents data from the European Community database on road accidents (CARE), more than 110 children under 14 years old who were passengers on PTW's were killed on the roads of the Community between 1991 and 2000. The European Commission is not aware of any specific national standard in the Member States apart from requiring the use of helmets by motorcycle drivers and passengers. The KID-SHELL project aims to design and develop a protection system addressed to children who are travelling as PTW (powered two-wheeler) passengers. The main aim of the first stage of this project is to know the main characteristics of the traffic accidents involving child motorcycle passengers and which injuries they suffer. This study takes into account both urban and non-urban areas and sorts accident scenarios and injuries suffered by PTW children passengers not only by frequency but also by severity.
Boix, Eloi, Azpeitia, José Antonio, Ferris, Sergi, Alba, Juan José
Pedestrian Impact on Low Friction Surface2014-01-04704/1/2014
A well-established methodology has often been used to calculate a speed-at-impact from the overall distance that a pedestrian is thrown as a result of a vehicle-pedestrian impact. (Searle, SAE #831622 and SAE #930659). The formulae were derived for use on typical road surfaces, such as asphalt, concrete, and grass. Significant testing has been done to validate the formulae on these normal surfaces. The current research was completed to assess if the same formulae are also applicable to lower-friction surfaces, e.g. snow, ice. Test dummies were impacted by automobiles or launched from a ramp in order to simulate the airborne trajectory of a vehicle-pedestrian collision. Speeds were measured with a radar unit and/or the analysis of high speed video. The overall distance traveled by the dummy from impact/launch to final rest was measured. A calculated friction value for the overall throw distance was based upon the known speed and distance and a known or approximated angle of takeoff. A measured friction value was obtained by dragging the dummy on the testing surface. For reference, a human volunteer was also dragged (manually) on the testing surface. The calculated speeds were compared to the radar speeds in order to determine the accuracy of the Searle formulae on each surface. The data were also analyzed using the standard friction values (0.66, 0.70 and 0.79 as stated in the Searle papers) to determine if the standard values were appropriate for use on all surfaces. The author conducted 97 tests, thereby providing adequate sample size for various statistical analyses. It was found that the Searle formulae did provide accurate results when the measured drag factor of the pedestrian dummy, on the low friction surface, was used.
Sullenberger, Greg A.
Relationship between Pedestrian Headform Tests and Injury and Fatality Rates in Vehicle-to-Pedestrian Crashes in the United States2013-22-000711/11/2013
Pedestrian protection evaluations have been developed to encourage vehicle front-end designs that mitigate the consequences of vehicle-to-pedestrian crashes. The European New Car Assessment Program (Euro NCAP) evaluates pedestrian head protection with impacts against vehicle hood, windshield, and A-pillars. The Global Technical Regulation No. 9 (GTR 9), being evaluated for U.S. regulation, limits head protection evaluations to impacts against vehicle hoods. The objective of this study was to compare results from pedestrian head impact testing to the real-world rates of fatal and incapacitating injuries in U.S. pedestrian crashes. Data from police reported pedestrian crashes in 14 states were used to calculate real-world fatal and incapacitating injury rates for seven 2002-07 small cars. Rates were 2.17-4.04 per 100 pedestrians struck for fatal injuries and 10.45-15.35 for incapacitating injuries. Euro NCAP style pedestrian headform tests were conducted against windshield, A-pillar, and hoods of the study vehicles. When compared with pedestrian injury rates, the vehicles' Euro NCAP scores, ranging 5-10 points, showed strong negative correlations (−0.6) to injury rates, though none were statistically significant. Data from the headform impacts for each of the study vehicles were used to calculate that vehicle's predicted serious injury risk. The predicted risks from both the Euro NCAP and GTR 9 test zones showed high positive correlations with the pedestrian fatal and incapacitating injury rates, though few were statistically significant. Whether vehicle stiffness is evaluated on all components of vehicle front ends (Euro NCAP) or is limited to hoods (GTR 9), softer vehicle components correspond to a lower risk of fatality.
Mueller, Becky, Farmer, Charles, Jermakian, Jessica, Zuby, David
Abdominal Twin Pressure Sensors for the Assessment of Abdominal Injuries in Q Dummies: In-Dummy Evaluation and Performance in Accident Reconstructions2012-22-001010/29/2012
The Abdominal Pressure Twin Sensors (APTS) for Q3 and Q6 dummies are composed of soft polyurethane bladders filled with fluid and equipped with pressure sensors. Implanted within the abdominal insert of child dummies, they can be used to detect abdominal loading due to the belt during frontal collisions. In the present study - which is part of the EC funded CASPER project - two versions of APTS (V1 and V2) were evaluated in abdominal belt compression tests, torso flexion test (V1 only) and two series of sled tests with degraded restraint conditions. The results suggest that the two versions have similar responses, and that the pressure sensitivity to torso flexion is limited. The APTS ability to detect abdominal loading in sled tests was also confirmed, with peak pressures typically below 1 bar when the belt loaded only the pelvis and the thorax (appropriate restraint) and values above that level when the abdomen was loaded directly (inappropriate restraint). Then, accident reconstructions performed as part of CASPER and previous EC funded projects were reanalyzed. Selected data from 19 dummies (12 Q6 and 7 Q3) were used to plot injury risk curves. Maximum pressure, maximum pressure rate and their product were all found to be injury predictors. Maximum pressure levels for a 50% risk of AIS3+ were consistent with the levels separating appropriate and inappropriate restraint in the sled tests (e.g. 50% risk of AIS3+ at 1.09 bar for pressure filtered CFC180). Further work is needed to refine the scaling techniques between ages and confirm the risk curves.
Beillas, Philippe, Alonzo, François, Chevalier, Marie-Christine, Lesire, Philippe, Leopold, Franck, Trosseille, Xavier, Johannsen, Heiko
Head Impact Mechanisms of a Child Occupant Seated in a Child Restraint System as Determined by Impact Testing2011-22-000611/7/2011
In side collision accidents, the head is the most frequently injured body region for child occupants seated in a child restraint system (CRS). Accident analyses show that a child's head can move out of the CRS shell, make hard contact with the vehicle interior, and thus sustain serious injuries. In order to improve child head protection in side collisions, it is necessary to understand the injury mechanism of a child in the CRS whose head makes contact with the vehicle interior. In this research, an SUV-to-car oblique side crash test was conducted to reconstruct such head contacts. A Q3s child dummy was seated in a CRS in the rear seat of the target car. The Q3s child dummy's head moved out beyond the CRS side wing, moved laterally, and made contact with the side window glass and the doorsill. It was demonstrated that the hard head contact, which produced a high HIC value, could occur in side collisions. A series of sled tests was carried out to reproduce the dummy kinematic behavior observed in the SUV-to-car crash test, and the sled test conditions such as sled angle, ECE seat slant angle and velocity-time history that duplicated the kinematic behavior were determined. A parametric study also was conducted with the sled tests; and it was found that the impact angle, harness slack, chest clip, and the CRS side wing shape affected the torso motion and head contact with the vehicle interior.
Yoshida, Ryoichi, Okada, Hiroshi, Nomura, Mitsunori, Mizuno, Koji, Tanaka, Yoshinori, Hosokawa, Naruyuki
A Study on the Optimal Design of IP Module Considering Performance of LRD A/BAG Deployment2011-28-004610/6/2011
The current advanced airbag regulation (FMVSS208) requires passenger cars and MPV either to have an automatic suppression system or to meet the LRD requirement on the passenger side. Recently, the car makers are choosing LRD requirement option and developing new LRD passenger airbag system. This paper presents a new methodology for improvement of airbag deployment using experimental and analytical research. The significant parameters were determined from statistical analysis of the experiment data. Basically, to deploy airbag normally, the ultra sonic knife or laser is used to cut the skin layer inside along with the gate line partially, so that deploying airbag can tear gate on instrument panel surface easily. As a result of the number of tests conducted at different conditions, this study was able to determine the range of relevant parameters. Additionally, using LRD simulation model, a parametric study was done, to figure out, which design factors mainly affect the low risk deployment of the passenger airbag, and some design improvements are presented.
Hyun, Kim, Mo, Ku Jun, Moon, S. S.
Basilar Skull Fractures by Crash Type and Injury Source2011-01-11264/12/2011
Purpose: This study investigates NASS-CDS data on basilar skull fractures by crash type and injury source for various crash scenarios to understand the injury risks, injury mechanisms and contact sources. Methods: 1993-2008 NASS-CDS data was used to study basilar skull fractures in adult front occupants by crash type and injury source. Injury risks were determined using weighted data for occupants with known injury status in 1994+ model year vehicles. In-depth analysis was made of far-side occupants in side impacts and rear crashes using the NASS electronic cases. Results: Basilar skull fractures occur in 0.507 ± 0.059% of rollovers and 0.255 ± 0.025% of side impacts. The lowest risk is in rear impacts at 0.015 ± 0.007%. The most common contact source is the roof, side rails and header (39.0%) in rollovers, the B-pillar (25.8%) in side impacts and head restraint (55.3%) in rear crashes. Seatbelt use significantly lowers the risk for basilar fracture from 1.77 ± 0.32% for unbelted to 0.20 ± 0.03% for belted (p ≺0.001) near-side occupants and from 0.92 ± 0.19% for unbelted to 0.057 ± 0.012% for belted (p ≺0.001) far-side occupants in side impacts. The electronic cases show basilar fractures typically occur in very severe crashes with high delta V and intrusion. Conclusions: Basilar skull fractures occur in 9.7 ± 0.9% of the crashes where an occupant experiences an AIS 3+ head injury. NASS case reviews show that basilar fractures typically occur in very severe crashes with multiple head injuries from contact with hard surfaces or by components stiffened from intrusion.
Parenteau, Chantal, Viano, David C.
Occupant Responses in Child Restraint Systems Subjected to Full-Car Side Impact Tests2010-01-10434/12/2010
Accident data show that the injury risks to children seated in child restraint systems (CRSs) are higher in side collisions than any other type of collision. To investigate child injury in the CRS in a side impact, it is necessary to understand the occupant responses in car-to-car crash tests. In this research, a series of full car side impact tests based on the ECE R95 test procedure was conducted. In the vehicle's struck-side rear seat location, a Q3s three-year-old child dummy was seated in a forward facing (FF) CRS, and a CRABI six-month-old (6MO) infant dummy was seated in a rear facing (RF) CRS and also was placed in car-bed restraint. In the non-struck side rear seat location, the RF CRSs also were installed. In addition to testing the CRSs installed by a seatbelt, an ISOFIX FF CRS and an ISOFIX RF CRS were tested. For the evaluations, occupant kinematic behavior and injury measures were compared. In all tests, the dummy heads were contained within the CRS shell during the entire impact event. In both the struck side FF CRS and RF CRS; the HICs were small, even though the dummy heads made indirect contact with the door beltline through the CRS side wing in these struck side CRSs. The dummy chest was loaded by an intruding door and the resulting chest deflection of the Q3s child dummy in the FF CRS was comparable with the injury assessment reference value. In the non-struck side, the loading of the CRABI 6MO seated in the CRS was substantially small. In the FF and RF ISOFIX CRS with a top tether, the acceleration of some body regions of the dummy could be high because the ISOFIX CRS moved from the initial phase of the impact and contacted the dummy at a high velocity. However, the CRS and the dummy displacement were small, which is an advantage of the ISOFIX CRS because occupant excursion could be a major source of injuries in the real-world accidents.
Yonezawa, Hideki, Tanaka, Yoshinori, Hosokawa, Naruyuki, Matsui, Yasuhiro, Mizuno, Koji, Yoshida, Ryoichi
A Comparison Study on Head Injury Risk in Car-to-Pedestrian Collisions in Changsha and Hannover2010-01-11674/12/2010
Vehicle traffic accidents have been extensively studied in various countries, but any differences in traffic accidents the studied areas have not yet been adequately investigated. This paper aims to make a comparison study of head injury risks and kinematics of adult pedestrian accidents in Changsha, China, and Hannover, Germany, as well as correlate calculated physical parameters with injuries observed in real-world accidents of the two cities. A total of 20 passenger cars versus adult pedestrian accidents were collected from the two areas of study, including 10 cases from Changsha and 10 cases from Hannover. Virtual accident reconstructions using PC-Crash and MADYMO software were performed. The in-depth study focused on head injury risks while kinematics were conducted using statistical approaches. The results of the analysis of the Chinese data were compared with those of the German data. The results indicated that differences regarding average head contact time, WAD, and scatter of head impact points on windshield were identified. Similarities in car front shape corridors, average head impact velocity and impact angle, relationships between vehicle impact velocity and head impact velocity, HIC value, and throw distance were shared by the two areas. The present results suggested that the EEVC test procedures can be considered as a basis of test procedures for pedestrian protection in China.
Chen, Yong, Yang, Jikuang, Otte, Dietmar
Development of Lower Neck Injury Assessment Reference Values Based on Comparison of ATD and PMHS Tests2010-01-01404/12/2010
Previous studies have suggested injury assessment reference values (IARVs) for lower neck injury based on scaled upper neck values. This study developed independent flexion and extension IARVs for the lower neck by matching Anthropomorphic Test Device (ATD) data to impact-tested post-mortem human subjects (PMHSs) with mid- to low-cervical spine injuries. Pendulum and sled tests with Hybrid III midsize male and small female ATDs were run under conditions mimicking those of published PMHS torso drop-sled tests and other PMHS studies. Measurements included upper and lower neck forces and moments, head acceleration, head rotation rate, and head/neck angles for the pendulum tests. Rear impacts corresponding to rigid seatback tests without a head restraint produced lower neck extension moments that increased dramatically with test severity, as measured by increasing delta-V and/or decreasing pulse duration. In contrast, upper neck extension moments increased only modestly with test severity, and all recorded peak values of upper neck force and moment, as well as calculated Nij, were below currently accepted IARVs. Our proposed lower neck IARVs are well below those previously published, which are based on simple scaling of upper neck IARVs. Frontal impact tests provided an indication that injuries may occur at lower neck flexion moment values that are below suggested tolerances; however, since the available PMHS dataset only included injured subjects for which the observations were left censored, no IARV could be determined. Relationships between peak moments at the upper and lower neck, as well as between male and female ATDs in tests of matching severity, were examined and compared to standard scaling used for previously proposed IARVs. Peak moment versus tension and compression forces were also evaluated, yielding additional data points for estimating critical intercepts for lower neck injury criteria (Nij).
Raasch, Christine, Carhart, Michael, Ivarsson, B. Johan, Lucas, Scott
Validation of an FE Lower Limb Model for a Child Pedestrian by Means of Accident Reconstruction2008-01-12404/14/2008
Validation of a child FE model is a great challenge due to the lack of sufficient data for children. In their previous study, the authors have developed a methodology for validating a child FE model by reconstructing pedestrian accidents and comparing predicted and observed injuries. However, the study reconstructed only one accident case and more validation cases were needed for enhanced confidence of the estimated material property. The current study therefore reconstructed two additional child pedestrian accident cases. In addition, published 3–point bending test results of child long bones were also used for quantitative assessment of the material property. The accident cases were taken from the PCDS and CIREN databases. Based on the information from the accident data, a multi–body simulation and optimization procedure were used to identify impact conditions. The estimated impact conditions were used to simulate the accident cases using the FE model with failure criteria. The predicted injuries using various sets of material parameters representing individual variation were compared with observed injuries. Published 3–point bending tests for child femora and tibiae were simulated using the models for these bones. The upper and lower bounds of the estimated individual variation of the material parameters were applied to the models to obtain predicted response corridors and to compare with the test data. The results of the FE accident reconstruction showed that the observed lower limb fracture patterns were reproduced within the estimated individual variation of material property. It was also found that most of the 3–point bending test results fell within the predicted force–deflection response corridors. Combining these two results, the accuracy of the estimated average material parameters and their individual variations were quantitatively assessed.
Ito, O., Okamoto, M., Takahashi, Y., Mori, F.
Feasibility Study of SIMon in Predicting Head Injuries in Children2007-01-24836/12/2007
The objective of this study was to assess the feasibility of SIMon (Simulated Injury Monitor) software package in predicting head injuries to children in automotive crashes. The human finite element head model (FEHM) within the SIMon was used for this study. Reconstruction of ten real world crashes involving children ages 4-8 years were conducted for this study. The selected cases were divided into five categories based on the type of head injury sustained by the child occupant. The categories were concussion only, skull fracture only, intracranial only, intracranial with skull fracture, and no injury. Two cases in each category were selected for reconstruction. Input for SIMon, was obtained from the reconstruction of real world crashes using EDSMAC4 (HVE environment) and MADYMO. EDSMAC4 in HVE environment was used to obtain the vehicle motion while MADYMO solver was used to obtain the occupant kinematics data in the crash. Finally, to reconstruct the loading on the skull and brain tissue in the crash, SIMon FEHM was used in the study. Three injury metrics were calculated: Cumulative strain damage measure (CSDM) - a correlate for diffuse axonal injury (DAI); Dilatational damage measure (DDM) - to estimate the potential of contusion; and Relative motion damage measure (RMDM) - to correlate for acute subdural hematoma (ASDH). Maximum values of the above injury metrics were plotted on the injury probability curve to assess the probability predicted by the SIMon FEHM. Based on this study, only 1 of the 10 cases with associated head injuries was correctly predicted by SIMon FEHM. The results showed correct trend of the probability of injury occurrence for the intracranial alone injury group; with low probability values. While with no injury cases, the SIMon FEHM showed the probability of occurrence of concussion type injuries. SIMon also failed to correctly predict cases under the concussion only injury group. The SIMon FEHM in combination with the injury tolerance curves, in their present form, could not be used to predict the various head injuries in the children.
Jain, Prashant, Ghati, Yoganand, Menon, Rajiv A.
Computer Analysis of Injuries to Rear Seat Child Occupants Restrained Using a Shared Lap/Shoulder Belt2007-01-25136/12/2007
The present study examines the effects of shared lap/shoulder belt use on the safety of rear seat, child occupants during frontal collisions. Using Mathematical Dynamic Modeling (MADYMO) software, a variety of simulated frontal sled tests were conducted. Eighteen simulated crash scenarios were examined. In each of the simulations either a single 6 Yr Hybrid III dummy or two 6 Yr Hybrid III dummies were placed in the rear, center seat position and restrained using a single lap/shoulder belt. Simulated sled test were conducted at change in velocity (ΔV)'s varying from 24 to 56kph, and principal direction of impact force (PDOF)'s varying from -30° to 30°. The peak resultant lap belt loads and lumbar spine loads experienced by each dummy were used to evaluate the relative potential for injury amongst dummies that were either belted alone or in a shared belt. The simulation results showed that, at most of the considered crash speeds and angles, the dummy restrained in its own belt experienced lower forces than did either of the dummies in the shared belt. An analysis of the dummies in the shared belt also supported prior research suggesting that likelihood of injury to a child restrained by a lap belt only is higher than that of a child that is restrained by a combined lap/shoulder belt.
Frieder, Russell S., Kumar, Sri
Inertial Neck Injuries in Children Involved in Frontal Collisions2007-01-11704/16/2007
There is a paucity of data regarding the potential for pediatric cervical spine injury as a result of acceleration of the head with no direct impact during automotive crashes. Sled tests were conducted using a 3-year-old anthropomorphic test device (ATD) to investigate the effect of restraint type and crash severity on the risk of pediatric inertial neck injury. At higher crash severities, the ATD restrained by only the vehicle three-point restraints sustained higher peak neck tension, peak neck extension and flexion moments, neck injury criterion (Nij) values, peak head accelerations, and HIC values compared to using a forward-facing child restraint system (CRS). The injury assessment reference values (IARVs) for peak tension and Nij were exceeded in all 48 and 64 kph delta-V tests using any restraint type. The test at a delta-V of 64 kph using only the vehicle belts as restraints resulted in peak upper neck tension, peak upper neck extension moment, and Nij values two times greater than the corresponding IARV. Only small differences were found in the injury metrics between a CRS installed with and without webbing tension except that head excursion was greater in the installation without webbing tension. These data show that the potential for neck injury exists for children involved in severe frontal crashes and restrained in either a forward-facing CRS or by vehicle belts-only, even in the absence of head contact.
Prange, Michael, Newberry, William, Moore, Tara, Peterson, Daniel, Smyth, Brian, Corrigan, Catherine
Risk Functions for Human and Porcine Eye Rupture Based on Projectile Characteristics of Blunt Objects2006-22-002611/6/2006
Eye ruptures are among the most devastating eye injuries and can occur in automobile crashes, sporting impacts, and military events, where blunt projectile impacts to the eye can be encountered. The purpose of this study was to develop injury risk functions for globe rupture of both human and porcine eyes from blunt projectile impacts. This study was completed in two parts by combining published eye experiments with new test data. In the first part, data from 57 eye impact tests that were reported in the literature were analyzed. Projectile characteristics such as mass, cross-sectional area, and velocity, as well as injury outcome were noted for all tests. Data were sorted by species type and areas were identified where a paucity of data existed, based on the kinetic and normalized energy of assaulting objects. For the second part, a total of 126 projectile tests were performed on human and porcine eyes. Projectiles used for these tests included blunt aluminum projectiles, BBs, foam pellets, Airsoft pellets, and paintballs. Data for each projectile were recorded prior to testing and high-speed video was used to determine projectile velocity prior to striking the eye. In part three the data were pooled for a total of 183 eye impact tests, 83 human and 100 porcine, and were analyzed to develop the injury risk criteria. Binary logistic regression was used to develop injury risk functions based on kinetic and normalized energy. Probit analysis was used to estimate confidence intervals for the injury risk functions. Porcine eyes were found to be significantly stronger than human eyes in resisting globe rupture (p=0.01). For porcine eyes a 50% risk of globe rupture was found to be 71,145 J/m2, with a confidence interval of 63,245 J/m2 to 80,390 J/m2. Human eyes were found to have a 50% risk of globe rupture at a lower, 35,519 J/m2, with confidence intervals of 32,018 J/m2 to 40,641 J/m2. The results presented in this paper are useful in estimating the risk of globe rupture when projectile parameters are known, or can be used to validate computational eye models.
Kennedy, Eric A., Ng, Tracy P., McNally, Craig, Stitzel, Joel D., Duma, Stefan M.
Exploring Pediatric Lower Extremity Injuries in Lateral Collisions with EDSMAC4 and GATB in HVE2006-01-14004/3/2006
This paper describes the application of the EDSMAC4 and GATB simulation modules of the Human Vehicle and Environment (HVE) software to analyze pediatric case occupants with fractures to the proximal part of the lower extremity due to lateral collisions. EDSMAC4 and GATB simulation results were compared with in-depth crash investigations for crash dynamics, injury mechanisms and occupant kinematics. These crash investigations were conducted as part of the Partners for Child Passenger Safety (PCPS) project at The Children's Hospital of Philadelphia (CHOP). In-depth investigations of near side impact crashes involving children (8-15 years old) with proximal lower extremity fractures were conducted. EDSMAC4 module was used to simulate vehicle dynamics and damage. The vehicle acceleration pulse generated from EDSMAC4 was used in the GATB module to predict the child occupant kinematics in these crashes. The EDSMAC4 results were consistent with the vehicle dynamics and damage pattern as measured in the crash investigation. The GATB analysis of occupant kinematics suggests that the initial orientation and subsequent motion of the pelvis and the direction of force influence the likelihood of injury. Different boundary conditions were adopted in the respective cases to understand the initial orientation and subsequent motion of the occupant pelvis. The scenarios of two side impact cases with no-, mid-, and maximum-intrusion along with different vehicle seat contours were also simulated. The results from the study sample show that the seat contour, intrusion and point of impact on the vehicle influenced the severity of injury to the proximal lower extremity in side impacts. The study also illustrates the utility of EDSMAC4 and GATB simulation models in HVE for better understanding of occupant kinematics in real world crashes. Although this approach offers certain distinct advantages in studying the injury causing factors, further assessment of this approach and capabilities of the simulation modules in HVE is required.
Menon, Rajiv A., Ghati, Yoganand, Mari-Gowda, Shresta
Characterizing Occipital Condyle Loads Under High-Speed Head Rotation2005-22-000211/9/2005
Because of the need to evaluate anthropomorphic test device (ATD) biofidelity under high-head angular accelerations, the purpose of the present investigation was to develop appropriate instrumentation for intact post mortem human subject (PMHS) testing, validate the instrumentation, and obtain information to characterize the response of the head-neck complex under this loading scenario. A series of rigid-arm pendulum, inertially loaded ATD tests was conducted. Head and neck ATD hydraulic piston chin pull tests were conducted. Subsequently, a series of PMHS tests was conducted to derive the response of the human head-neck under high-rate chin loading. Finally, Hybrid III and THOR-NT ATD head-neck systems were evaluated under the same scenario as the PMHS. A parametric analysis for center of gravity (CG) location and accelerometer orientation determined that even small errors (± 3 mm or 2 degrees), produced errors in the force and moment calculations by as much as 17%. If the moment of inertia (MOI) term was varied by 5%, resulting moment calculations were affected by as much as 8%. If the 5% error in MOI was used to compute occipital condyle moments, and results compared to upper load cell derived moments, peaks differed by as much as 24%. The head CG and mass MOI should be directly measured for each preparation to obtain accurate results. The injury run on each specimen resulted in predominantly C1-C2 separations or partial separations. The 50th percentile probability of AIS=2+ neck injury using tensile force was about 2400 N; for AIS=3+ neck injury the 50th percentile risk was about 3180 N. When inserting extension moment as the criteria, the 50th percentile probability of an AIS=2+ injury was 51 Nm. The AIS=3+ extension moment at the 50th percentile probability was 75 Nm. The new THOR-NT ATD head-neck produced more biofidelic responses with an alternate head-neck junction design compared to the Hybrid III ATD.
Pintar, Frank A., Yoganandan, Narayan, Baisden, Jamie
Study of BioRID II Sled Testing and MADYMO Simulation to Seek the Optimized Seat Characteristics to Reduce Whiplash Injury2004-01-03363/8/2004
Development of anti-whiplash technology is one of the hottest issues in the automotive safety field because of the frequent occurrence of rear impact accidents. We analyzed the whiplash mechanism and conducted a study to seek the optimized seat characteristics with BioRID II and MADYMO simulations. A parameter study was made to construct a conceptual theory to decrease NIC, Neck Injury Criteria, with the MADYMO model. As a result of the study, head restraint position and seatback stiffness were found to affect dummy movement and injury values. Applying the NIC mechanism and the influential parameters to the MADYMO model, the optimized seat characteristics for whiplash prevention were obtained.
Kaneko, Naoki, Wakamatsu, Masayuki, Fukushima, Masanobu, Ogawa, Shigeru
Optimized Restraint Systems for Various-Sized Rear Seat Occupants in Frontal Crash2003-01-12303/3/2003
Of the injuries sustained by belted rear occupants in a frontal collision event in Japan, the neck and the head are the regions of the body most likely to be injured, while children and female occupants are accounting for the highest rate of injuries. For the purpose of reducing rear seat occupant injuries, the occurrence mechanism of neck and head injuries is clarified by sled tests with the current rear seat belt system. When a high load is applied to the occupant via the seat belt, the occupant experiences sudden deceleration of the chest, resulting in a great relative velocity difference between the head and the chest. This causes injury to the occupant's neck and head. To reduce occupant injuries, therefore, it is important to minimize the relative velocity difference by control of belt load. This paper proposes the concept of optimal belt load control and summarizes parameter study results that have been conducted to verify the validity of the concept using occupant simulation, MADYMO, ranging from 6-year-old dummy (hereinafter “6Yo”), AF05, and AM50 to AM95. Also, in this paper is mentioned the optimal belt control characteristics found through the study.
Kawaguchi, Kenji, Kaneko, Naoki, Iwamoto, Tatsuhiko, Fukushima, Masanobu, Abe, Akiko, Ogawa, Shigeru
Field Data Analysis of Rear Occupant Injuries Part I: Adults and Teenagers2003-01-01533/3/2003
Since more occupants are using rear seats of vehicles, a better understanding of priorities for rear occupant protection is needed as future safety initiatives are considered. A two-part study was conducted on occupant injuries in rear seating positions. In Part I, adult and teenage occupants ≥13 years of age are investigated. In Part II, children aged 4-12 years old and toddlers and infants aged 0-3 are studied separately because of the use of infant and child seats and boosters involve different injury mechanisms and tolerances. The objectives of this study on adult and teenager, rear-seated occupants (≥13 years old) are to: 1) review accident data, 2) identify the distribution of rear occupants, and 3) analyze injury risks in various crash modes, including rollovers, frontal, side and rear impacts. Three databases were investigated: NASS-CDS, GES and FARS. Results indicate that there is <25% probability of having a rear occupant of any age for every driver involved in any of the databases, and the probability is increasing with accident year. With respect to crash type, the risk for rear occupants to be killed was highest in side and rear impacts and in rollovers, while the rate for serious injury (MAIS 3+) was highest in rollovers and side impacts. However, in comparison to drivers and the right-front passengers, the fatality risk and serious injury rate were greatest in rear impacts. 63% of the rear occupants were unbelted in FARS, while about 40% were unbelted in NASS. Unbelted adult occupants had a higher risk of serious injury than lap belted and lap/shoulder belted occupants. In the weighted data, front seat occupants have a lower rate of serious injury than 2nd and 3rd row seat occupants. However, lap/shoulder belted occupants have a lower risk to be seriously injured in the 2nd and 3rd row seat. For the lap and shoulder belted adult 2nd rear seats occupants, thoracic injuries were most common. They often resulted from contact with the seatbelt. Current field injury data and the literature point to the following possible priorities for adults and teenagers using rear seats: 1) load-limiting belts with cinching and good restraint geometry, 2) EA material for the seatback, side interior and B-pillar, 3) reduced contact velocity with seatback, side interior and B-pillar, 4) improved containment with inflatable side curtains and laminated side glass, and 5) possible technologies such as inflatable belts.
Parenteau, Chantal, Viano, David C.
Field Data Analysis of Rear Occupant Injuries Part II: Children, Toddlers and Infants2003-01-01543/3/2003
Child safety continues to be an important issue in automotive safety for many reasons, including reported cases of serious injury from airbag deployments. As a result of extensive public education campaigns, most children are now placed in rear seats of vehicles. Accordingly, a more precise understanding of rear-seat occupant protection is developing as the second and third rows have become the primary seating area for children in SUVs, vans and passenger cars. The objective of this study was to review field crash and injury data from rear seats, identify the distribution of children and infants in rear seats, and analyze injury risks in various crash modes. The database used was the 1991-1999 NASS-CDS. When looking at crash configurations for 1st and 2nd row children, rollover crashes involved the highest incidence of MAIS 3+ injury, followed by frontal and side impacts. Lap-shoulder belt usage was similar for 1st and 2nd row children. For lap-shoulder belted children aged 4-12 in the rear seat, the leading MAIS 3+ injuries in frontal crashes are to the upper extremities (33%) and head (30%). The source of injury is typically contact with the seatback, head restraint or interior. Lower extremity injury (20%) is generally due to B-pillar or seatback contact. For unbelted children, the leading injuries are to the head (50%) and upper extremity (29%); and, the sources of injury include the seatback, B-pillar and interior contact. 74% of infants and children 0-3 years old that are exposed to tow away crashes are in the 2nd row as compared to 22% in the front passenger seat and 4% in other positions. The rate of serious injury is 1.1% in the 2nd row and 1.2% in the front passenger seat; thus, the rate is statistically similar (p < 0.10). Unbelted 0-3 year old children have a 5.8 times greater risk of serious injury than those restrained in a child seat. There are too few cases of vehicle crashes with airbags available to assess relative risk differences between front and 2nd row seating of 0-3 year old children. Based on the most frequent injuries by restraint use and crash type, a series of safety areas are identified that may help improve protection for children and others in the rear seating zone.
Parenteau, Chantal, Viano, David C.
Pediatric Pelvic Fractures in Side Impact Collisions2002-22-001511/11/2002
Little is known about the mechanism of pelvic injury in the pediatric population, an age range over which the pelvis undergoes tremendous structural change. We hypothesize that these structural changes influence pelvic fracture injury mechanisms. A probability sample of children under age 16 years in crashes were enrolled in an on-going crash surveillance system which links insurance claims data to telephone survey and crash investigation data. 15,725 children in side impact collisions were studied. Risk of pelvic fracture in side impact collisions was estimated and factors associated with these injuries were identified. Eight cases were examined using in-depth investigation to identify the injury mechanisms. Of our study sample, 0.10% of children suffered a pelvic fracture. The typical child with a pelvic fracture was a 12-15 year old female front row occupant of a passenger car involved in a struck side collision with intrusion. Analyses of the in-depth crash investigations determined that the developmental age of the child was the most important parameter associated with the type of pelvic fracture. Children 8-11 years experienced isolated pubic rami fractures, whereas children 12-15 years experienced multiple fractures of the pelvic ring. This distinct injury pattern is directly related to the ossification during puberty of the cartilage connecting the three bones of the pelvis. A secondary influence on the injury pattern was the geometrical and stiffness incompatibilities between impact partners that resulted in vehicle deformation and rotation of the vehicle seat. In the effort to improve the side impact protection of vehicles, attention should be paid to improved structural chassis design that minimizes the dynamic deformation of the seat.
Arbogast, Kristy B., Mari-Gowda, Shresta, Kallan, Michael J., Durbin, Dennis R., Winston, Flaura K.
Performance of Depowered Air Bags in Real World Crashes2002-01-01863/4/2002
During the period 1992 through 2000, the William Lehman Injury Research Center collected crash and injury data on 141 drivers and 41 right front passengers in frontal crashes with air bag deployment. Among these cases were twenty-eight cases with depowered air bags. The paper compares the crash characteristics for injured occupants in vehicles with 1st generation and depowered air bags. The population with 1st generation air bags contains unexpected fatalities among as well as fatalities at low delta-V's. To date, these populations are absent among the fatally injured occupants of vehicles with depowered air bags. The depowered cases include both belted and unbelted survivors at crash severities above 40 mph delta-V. The maximum injury in these severe crashes was AIS 3 with no evidence of unsatisfactory air bag performance. However, serious internal chest injuries were observed in two cases with unrestrained drivers at crash severities of 19 and 24 mph.
Augenstein, J., Perdeck, E., Stratton, J., Digges, K., Steps, J.
Development of a Reusable, Rate-Sensitive Abdomen for the Hybrid III Family of Dummies2001-22-000211/1/2001
The objective of this work was to develop a reusable, rate-sensitive dummy abdomen with abdominal injury assessment capability. The primary goal for the abdomen developed was to have good biofidelity in a variety of loading situations that might be encountered in an automotive collision. This paper presents a review of previous designs for crash dummy abdomens, a description of the development of the new abdomen, results of testing with the new abdomen and instrumentation, and suggestions for future work. The biomechanical response targets for the new abdomen were determined from tests of the mid abdomen done in a companion biomechanical study. The response of the abdominal insert is an aggregate response of the dummy’s entire abdominal area and does not address differences in upper versus lower abdominal response, solid versus hollow organs, or organ position or mobility. While the abdomen developed has demonstrated good biofidelity in rigid bar, seat belt and airbag loading situations, some work remains to be done before it can be used in crash testing.
Rouhana, Stephen W., Elhagediab, Ali M., Walbridge, Anthony, Hardy, Warren N., Schneider, Lawrence W.
The influence of rear loading on the protection of child car occupants in child restraints2001-06-01476/4/2001
The risk of injury to child car occupants can be markedly reduced by their use of appropriate child restraints. These can be child seats with their own integral harness, child booster seats or booster cushions in association with adult seat belts or, if the child is old and large enough, by the use of adult seatbelts alone. However, the protection afforded can be negated if there is significant loading to the child and restraint through the car seat backrest. This paper describes analyses of accident data to demonstrate the occurrence of this effect in field accidents and presents the results of dynamic tests performed to explore the effect on different restraint types of limiting the load intrusion from the rear. Results of tests with child seats with integral harnesses show that head forward excursion is the main concern, the R44 limits being impossible to meet if the seat back is allowed to move as far forward as the R-point. Where the child is restrained by the adult belt, belt forces in excess of the injury tolerance for adults were exceeded, raising to very high levels for backrest movement up to 150 mm ahead of the R-point.
Le Claire, M., Visvikis, C.
A NEW NECK INJURY CRITERION CANDIDATE FOR REAR-END COLLISIONS TAKING INTO ACCOUNT SHEAR FORCES AND BENDING MOMENTS2001-06-01756/4/2001
It is generally accepted today that the cervical spine of a car occupant who is involved in a low-speed rear end impact may suffer from soft tissue neck injuries leading to long-term impairment. Therefore, to assess the risk of sustaining such injuries is a major issue in traffic safety, and various neck injury criteria are being discussed for this purpose. In this study a new candidate for such an injury predictor, called Nkm, was developed. Results from a total of 37 sled tests with various car front seat models were evaluated to validate the new criterion. These results indicate that the new criterion offers the possibility to assess the kinematic phase of forward motion of a rear-end collision. In contrast, the NICmax which was also calculated for these tests allows to evaluate the retraction phase only. Furthermore, the influence of the seat design on its protective potential could be related to the Nkm values obtained.
Schmitt, K.-U., Muser, M. H., Niederer, P.
SIDE AIRBAGS: EVALUATING THE BENEFITS AND RISKS FOR RESTRAINED CHILDREN2001-06-02206/4/2001
Child dummies were seated in size appropriate child restraints and exposed to in-vehicle, static, side mounted airbag deployments as well as full scale side impact crash tests. The child seat sample included rear and forward facing child restraints and booster seats. Anthropomorphic test dummies (ATD) included an 18 month infant and fully instrumented Hybrid III 3 year old and Hybrid III 6 year old child dummies. Preliminary results suggest that properly restrained infants and children occupying age appropriate child seats may receive some protective benefits from side airbags provided the child seat and the child occupant are correctly positioned.
Tylko, Suzanne, Dalmotas, Dainius
An Energy Based Analysis for Neck Forces in Frontal Impacts2000-01-01663/6/2000
In 1997 Mertz, Prasad and Irwin [1] have described a technique for the development of injury risk curves for measurements made with the CRABI and Hybrid III family of biofidelic child and adult dummies that are used to evaluate restraint systems in frontal collision simulations. They further developed normalized injury risk curves for neck tension, neck extension moment, combined neck tension and extension moment for adults and children. The approach described by Mertz et al [1], is based on lines of equivalent stress and uses the maximum normal stress theory of failure to impose limits of the risk of injuries. In this paper a complementary approach is described based on the maximum energy of failure and lines of constant energy. A special case of this approach in 1D is used to develop the assessment values obtained by Mertz et al [1]. Limitations and advantages of the energy based approach are described, with especial emphasis on future implementation.
Hassan, Joseph E., Nusholtz, Guy
The Influence of Occupant and Vehicle Characteristics on Risk of Pediatric Air Bag Injury99SC2710/10/1999
A case-comparison study was conducted of children between one and twelve years of age exposed to passenger air bag (PAB) deployment. Cases were children fatally injured by PAB exposure and were investigated by the Special Crash Investigation Program of NHTSA. For comparison, children exposed to PABs, but suffering minor injury were identified through the Partners for Child Passenger Safety (PCPS) Study, a system utilizing insurance claims data for crashes involving children. The crash severity as measured by Delta V was not significantly different between the two groups. Restraint status in conjunction with pre-impact braking highly influenced injury outcome indicating the importance of pre-crash positioning as a risk factor in child exposure to PAB deployment. Other related variables such as child size and age reinforced the importance of restraint. No vehicle characteristics or interior vehicle space measurements were significantly different between the two groups. Current vehicle designs cannot be differentiated with respect to their potential for producing serious child injuries due to PAB deployment. Researchers must continue to examine the entire spectrum of occupant injury severity in order to fully understand injury risk and ensure that future design of vehicles considers the safety of all occupants, including children.
Arbogast, K. B., Durbin, D. R., Resh, B. F., Winston, F. K.
Simulation Method for Dynamic Out-of-Position Crash Tests1999-01-06383/1/1999
The on-going industry effort to improve air bag systems for out-of-position occupants has created the need to reexamine the existing design criteria and development means to be used in the implementation of advanced air bag technologies. Development procedures and test techniques must be augmented to include appropriate testing of the out-of-position occupant. This paper will review the development of a unique dynamic test fixture and test methodology to simulate the pre-deployment movement of an occupant concantenated with a conventional crash pulse on a HYGE sled. This test methodology provides for efficient development of dynamic occupant tracking systems, biomechanic algorithms and restraint system controls.
Frech, Hank, Burley, Edward, Hill, Timothy W., Rossey, Mike, Schulz., Kurt
Development of a Sled Side Impact Test for Child Restraint Systems9862095/31/1998
Currently the majority of Child Restraint Systems (CRS) in the UK are approved to ECE Regulation 44 Amendment 03. This focuses on the crash performance of the CRS under frontal and rear impacts and does not include a sled side impact test. Although standards from Australia and New Zealand have for some time contained such a test, they do not include an element reproducing the effects of intrusion. Intrusion is a major factor in serious and fatal injuries to children in CRS. This paper describes a research program conducted to develop a simple side impact test which attempts to reproduce the effects of side structure intrusion on a CRS installed in a car on the struck side. A hinged door was mounted on the Middlesex University test sled, which, when opened contacted a CRS restrained on the ECE R 44 test seat mounted laterally on the sled. The door was opened under impact conditions when it struck an auxiliary impactor at the beginning of the sled deceleration phase. The chest and head response of ATDs restrained in current and prototype CRS was measured. These were compared with full-car side impacts conducted at TRL. The results suggested that the peak response of the ATD was representative of the car/barrier impacts but the energy input to the CRS as a function of time needs more development.
Paton, I. P., Roy, A. P., Lowne, R.
Cervical Distraction Injuries to Children97330611/12/1997
Spinal cord injuries caused by distraction forces to children restrained in the rear seat seats of passenger vehicles are not often reported in the medical or automotive safety literature. This paper adds several cases not previously identified. Other incidents of distraction injuries to the thoracic region are mentioned as part of the cases reported.
Slavik, Donald H.
Injury Risks, Misuse Rates and the Effect of Misuse Depending on the Kind of Child Restraint System97330911/12/1997
The compulsory use of child restraint systems (CRS) in cars which came into force on 1st April 1993 led to a considerable increase in the belting rate of children in Germany, but between 30% and nearly 60% of the children aged 0<12 years are only restrained by an adult belt (lap or three-point belt). On the basis of a new accident material of the German Motor Insurers (593 restrained children 0 to 12 years involved in 448 car accidents) the injury risk of children being belted with an adult belt only is compared to those injury risks of children being restrained in different types of CRS (415-point belt, 3-point belt, impact shield, booster cushion). The form of restraint „child with an adult belt only” involves disproportionately high risks. In retrospective accident studies it is relatively difficult to get detailed information about the frequency and the exact kind of CRS misuse. Therefore 250 users of CRS were observed and interviewed. Only in one third of these observations the CRS were correctly mounted; depending on different types of CRS the misuse rates lay between 20 and 90%. To check up the effect of the most frequent and most severe kinds of misuse 20 crash tests with wrong fitted CRS were carried out; for this reason tests with an ECE sled and with a cut-off car body have been performed. Depending on the kind of CRS a partly considerable reduction of the safety effect of CRS could be observed in case of misuse. Protection against misuse by a proper design has to be given highest priority for the safety improvement of future CRS.
Hummel, Th., Langwieder, K., Finkbeiner, F., Hell, W.
Children as Front Seat Passengers Exposed to Airbag Deployments97329511/12/1997
From a review of 722 “airbag” crashes investigated by UMTRI personnel, there were 117 front seat passengers exposed to passenger side airbag deployments. The majority of these were 16 years of age or older (90 of the 117), with 20 passengers. 11 years of age or younger. Two cases, both fatalities, will not be described, for these crashes have been investigated also by NHTSA's Special Crash Investigation Program personnel. The crashes and injuries of these 18 passengers are described. In this group there were 13 children who had MAIS-1 level injuries and two sustained an MAIS-2 injury. One child was without injury, and two had MAIS-5 level injuries. The description of the crash and of the major injuries sustained are detailed in each of the case capsule descriptions. Most of the children were properly restrained.
Huelke, Donald F.
Biomechanically Based Design and Performance Targets for a 3-Year Old Child Crash Dummy for Frontal and Side Impact97331611/12/1997
The Q-series of child dummies is a new family of advanced child dummies covering the complete child population up to 12 years. The Q-series' design is not only advanced in terms of its biomechanical basis, it is also developed to be used in both front and side impact making it the first “multi-directional” series of (child) dummies. This paper presents the functional targets for the Q-series, a set of biomechanically based design and performance targets for a 3-year-old dummy and the validation of the prototype version of the 3-year-old Q-dummy, the Q3.
Barnes, Andy, Platten, Geoff, van Ratingen, Michiel R., Twisk, Dirk, Schrooten, Mark, Beusenberg, Marc C.
The Effect of Top Tether Strap Configurations on Child Restraint Performance97330411/12/1997
This paper reports the results of a study to determine the effects of a top tether strap on the performance of child restraint systems (CRS). Four commercially available CRSs and the CanFIX were tested. All restraints tested had a similar design T-shield type harness system to minimize harness variability. As part of the test matrix, tether webbing, tether height and tether slack were varied. The dummies used for testing were the 12-and 18-month CRABI. Head and chest acceleration, head excursion, upper and lower neck loads and resultant moments were recorded. Although the presence of slack in the tether strap degrades the performance of the CRS, a tether strap with slack present improved the response of a dummy restrained in a CRS when compared to an identical tetherless restraint. With maximum slack, the results for the restraint condition approached results from a tetherless condition while still demonstrating a slight benefit.
Legault, France, Gardner, Bill, Vincent, Alex
Nonfatal Air Bag Deployments Involving Child Passengers97329711/12/1997
This study describes nonfatal interactions between children and front passenger air bags. Twelve surviving children aged 12 and younger who experienced passenger air bag deployments were identified from hospital emergency department records and police accident reports. Data from crash reconstructions and medical records were analyzed to determine mechanisms responsible for each injury sustained. Four of six children in safety seats and one of six children restrained in lap/shoulder belts sustained significant brain injuries. It is recommended that infant seats and forward facing safety seats be placed in the rear seats of vehicles equipped with passenger air bags.
Gotschall, Catherine S., Eichelberger, Martin R., Morrissey, J. René, Better, Allison I., Reardon, Jean
Children in Adult Seat Belts and Child Harnesses: Crash Sled Comparisons of Dummy Responses97330811/12/1997
Many children are still restrained in adult belts alone, even though an adult seat belt is not optimal for small occupants for whom a child restraint would be safer and more desirable. Therefore, a test program was designed to investigate the impact responses of three dummies representing children aged 18 months, three years and six years. The simulations were sled runs at a delta-V of 48 km/h with accelerations of 27 g. The dummies were restrained in adult lap/shoulder, lap-only and child harness belt systems. Neck shear, axial tension and bending moments were rather higher with a lap/shoulder than a lap-only belt. However, the lap/shoulder system minimised dummy head and upper torso excursion, head acceleration and pelvic accelerations. Lap belt loads, head accelerations, HIC and chest accelerations were higher with the lap belt alone than with the lap/shoulder belt. The lap belt also permitted considerable excursion and head contact with the hard frame of the test seat, which affected HIC and neck loads. The lap/harness system gave generally the highest head and neck forces.
Brown, Julie, Griffiths, Michael
Injury Risk Curves for Children and Adults in Frontal and Rear Collisions97331811/12/1997
This paper describes the development of injury risk curves for measurements made with the CRABI and Hybrid III family of biofidelic child and adult dummies that are used to evaluate restraint systems in frontal and rear-end collision simulations. Injury tolerance data are normalized for size and strength considerations. These data are analyzed to give normalized injury risk curves for neck tension, neck extension moment, combined neck tension and extension moment, sternal compression, the rate of sternal compression, and the rate of abdominal compression for children and adults. Using these injury risk curves dummy response limits can be defined for prescribed injury risk levels. The injury risk levels associated with the various injury assessment reference values currently used with the CRABI and Hybrid III family of dummies are noted.
Mertz, Harold J., Prasad, Priya, Irwin, Annette L.
Air Bags and Children: Results of a National Highway Traffic Safety Administration Special Investigation into Actual Crashes96243811/1/1996
Air bags have been and continue to be an effective, life-saving technology. The National Highway Traffic Safety Administration (NHTSA) has estimated that air bags have saved almost 1,500 lives, with an estimated 569 lives saved in 1995 alone. However, the increasing availability of air bags in passenger vehicles and light trucks has seen a concomitant rise in the report of injuries related to air bag deployment. While the vast majority of these injuries has been minor, the exposure of children to passenger-side air bag deployments has resulted in reports of more serious injuries. The objective of this study was to examine the interaction of air bags and children in actual crash scenarios. Investigations were conducted as part of the NHTSA's Special Crash investigation Program. This paper will present a case series of more than twenty serious or fatal injuries in children attributed to air bag deployment. Cases of children whose lives were saved by air bags, the “success stories,” were not included in the series because these cases were not reported to the NHTSA. Analysis of the investigations included determination of vehicle dynamics, occupant kinematics and injury patterns in order to define injury mechanisms.
Winston, Flaura Koplin, Reed, Richard
Comparison of the AIS-85 and AIS-90 with NASS-939600952/1/1996
Two injury severity systems in widespread use by automobile manufacturers, motor vehicle accident investigators, researchers and trauma centers are the Abbreviated Injury Scale (AIS) and the National Accident Sampling System (NASS) Occupant Injury Classification [1][2][3]. Updates of these systems by AAAM (AIS-90) and NHTSA (NASS93), prevent data collected in differing versions of these systems from being accurately combined or trended without severity adjustments. This paper discusses and summarizes major differences between these coding systems, compares the number and percent distribution of injuries by severity, and reviews the need for methods to adjust severity.
Garthe, E. A.
Injury Assessment Reference Values for the CRABI 6-Month Infant Dummy in a Rear-Facing Infant Restraint with Airbag Deployment9508722/1/1995
The purpose of this paper is to establish injury assessment reference values specific to the CRABI 6-Month infant dummy for use in evaluating the interaction of rear-facing infant restraints with a deploying passenger airbag. The available literature on the biomechanics of child injury and mechanical response and the results of impact tests with various child and infant dummies are reviewed and summarized. Estimations of the injury assessment reference values for use with the CRABI 6-Month dummy are made using scaling techniques based on the principles of dimensional analysis and dummy test data from infant restraint tests under conditions where injuries are not likely to occur. The information developed in this report will allow the assessment of injury potential in tests of the interaction of passenger airbags with rear-facing infant restraints. This issue is of particular importance to vehicles with only front seats, such as pickup trucks and sport vehicles.
Melvin, John W.
Biomechanical Analysis of Tractor Induced Head Injury9417269/1/1994
Head injury is a serious threat to lives of people working around farm machinery. The consequence of head injuries are costly, paralytic, and often fatal. Clinical and biomechanical data on head injuries are reviewed and their application in the analysis of head injury risk associated with farm tractor discussed. A significant proportion of tractor-related injuries and deaths to adults, as well as children, is due directly or indirectly to head injury. An improved injury reporting program and biomechanical studies of human response to tractor rollover, runover, and falls, are needed to understand mechanisms of the associated head injury.
Yoganandan, Narayan, Sances, Anthony, Ewing, Channing L., Thomas, Daniel J.
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