Browse Topic: Injury causation

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Recommendation for Acceptable Operating Parameters of Heated Automobile Seats in Order to Mitigate Occupant InjuryJ3047_202012 (Current)12/7/2020
This recommended practice will promote a temperature and duration guideline that mitigates the risk of thermal injuries to the heated seat user. In addition, recommendations are established to indicate to the user when the heater is operating, and warnings that should be included in the vehicle literature.
Heated Seats Standards Committee
Human Response and Injury Resulting from Head Impacts with Unmanned Aircraft Systems2019-22-00023/31/2020
Unmanned aircraft systems (UAS), commonly known as drones, are part of a new and budding industry in the United States. Economic and public benefits associated with UAS use across multiple commercial sectors are driving new regulations which alter the stringent laws currently restricting UAS flights over people. As new regulations are enacted and more UAS populate the national airspace, there is a need to both understand and quantify the risk associated with UAS impacts with the uninvolved public. The purpose of this study was to investigate the biomechanical response and injury outcomes of Post Mortem Human Surrogates (PMHS) subjected to UAS head impacts. For this work, PMHS were tested with differing UAS vehicles at multiple impact angles, locations and speeds. Using a custom designed launching device, UAS vehicles were accelerated into the frontal, parietal, or vertex portions of subjects’ craniums at speeds up to 22 m/s. Of the 35 UAS impacts carried out, one AIS 2+ injury was observed: a 13 cm linear skull fracture resulting from a Phantom 3 impact. Additionally, injury risk curves used in automotive testing were found to over predict the risk of injury in UAS impact scenarios. Finally, localized skull deformation was observed during severe impacts; the effect that this deformation had on measured kinematics should be further evaluated. Overall, the study found that AIS 2+ head injuries may occur as a result of UAS impacts and that automotive injury metrics may not be able to accurately predict head injury risk in UAS impact scenarios.
Stark, David B., Willis, Arrianna K., Eshelman, Zach, Kang, Yun-Seok, Ramachandra, Rakshit, Bolte IV, John H., McCrink, Matthew
Development of a Subhuman Primate Brain Finite Element Model to Investigate Brain Injury Thresholds Induced by Head Rotation2019-22-00033/31/2020
An anatomically detailed rhesus monkey brain FE model was developed to simulate in vivo responses of the brain of sub-human primates subjected to rotational accelerations resulting in diffuse axonal injury (DAI). The material properties used in the monkey model are those in the GHBMC 50th percentile male head model (Global Human Body Model Consortium). The angular loading simulations consisted of coronal, oblique and sagittal plane rotations with the center of rotation in neck to duplicate experimental conditions. Maximum principal strain (MPS) and Cumulative strain damage measure (CSDM) were analyzed for various white matter structures such as the cerebrum subcortical white matter, corpus callosum and brainstem. The MPS in coronal rotation were 45% to 54% higher in the brainstem, 8% to 48% higher in the corpus callosum, 13% to 22% higher in the white matter when compared to those in oblique and sagittal rotations, suggesting that more severe DAI was expected from coronal and oblique rotations as compared to that from sagittal rotation. The level 1+ DAI was associated with 1.3 to 1.42 MPS and 50% CSDM (0.5) responses in the brainstem, corpus callosum and cerebral white matter. The mass scaling method, sometimes referred to as Holbourn's inverse 2/3 power law, used for development of human brain injury criterion was evaluated to understand the effect of geometrical and anatomical differences between human and animal head. Based on simulations conducted with the animal and human models in three different planes - sagittal, coronal and horizontal - the scaling from animal to human models are not supported due to lack of geometrical similitude between the animal and human brains. Thus, the scaling method used in the development of brain injury criterion for rotational acceleration/velocity is unreliable.
Arora, Tushar, Zhang, Liying, Prasad, Priya
Bone Bandage Soaks Up Pro-Healing Biochemical to Accelerate RepairTBMG-360162/1/2020
Researchers at Duke University have engineered a bandage that captures and holds a pro-healing molecule at the site of a bone break to accelerate and improve the natural healing process. In a proof-of-principle study with mice, the bandage helped to accelerate callus formation and vascularization to achieve better bone repair by three weeks.
5 Ws of Microlattice Pads for Improved HelmetsTBMG-359842/1/2020
Football players and other athletes, motorcycle riders, soldiers, and anyone wearing protective helmets made with the new microlattice pads will have greater protection from both single hits and a series of impacts.
Engineers 3D Print Flexible Mesh for Ankle and Knee BracesTBMG-349848/1/2019
Hearing aids, dental crowns, and limb prosthetics are some of the medical devices that can now be digitally designed and customized for individual patients, thanks to 3D printing. However, these devices are typically designed to replace or support bones and other rigid parts of the body, and are often printed from solid, relatively inflexible material.
Residual Injury Situation and Accident Characteristics of Severe Motorcycle Accidents2019-01-06384/2/2019
The total number of persons severely and fatally injured in road traffic accidents has reduced considerably in recent decades. However, the number of motorcyclists involved in accidents has not reduced to the same extent, and some countries have even recorded an increase. The aim of this study is to analyse the circumstances of motorcycle accidents in Germany involving vehicles with a cubic capacity of over 125 cm3 with particular reference to severely or fatally injured riders. An analysis is to be made of the characteristics and patterns of injuries suffered by the most severely injured motorcyclists and proposals developed for injury prevention. The study included accident data from 464 motorcycle accidents collected in Hanover and Dresden between 2010 and 2015 by an academic research team in the course of the GIDAS project (German In-Depth Accident Study). This data represents a statistically representative sample from real accidents occurring in Germany. The analysis of the current injury situation shows that motorcyclists are often severely injured, i.e. suffered injuries of grade MAIS 3+ (so called serious injuries) in 16.9% of cases and thus around 9 times more frequently than car occupants. Motorcyclists wearing helmets suffered head injuries in approx. 20 % of cases. The serious injuries sustained were in particular skull fractures, including base of the skull and traumatic brain injuries are rare. Severe thoracic injuries included in particular rib and shoulder/clavicle fractures, often accompanied by injuries to internal organs. In terms of spinal injuries, the most common serious injuries were fractures of the thoracic spine, followed by fractures of the lumbar spine and cervical spine. In the abdominal area there were often severe injuries in the form of fractures in the pelvic area and accompanying injuries to internal organs. Arm injuries included, besides minor injuries (grazes, bruises, etc.), most commonly fractures of the hands/fingers and forearms, followed by elbow and upper arm fractures. Leg injuries seen in particular were femoral fractures as well as injuries to the muscles and tendons around the knee, also fractures of the shin and calf bones. Around the feet there were many fractures and dislocations of the wrist and ankle joints, as well as toes. The causes of the injuries, which were recorded in detail in the study for the various regions of the body and individual injuries, were most often caused by impact with the road and collision with objects and solid vehicle structural elements of cars and trucks. Serious injuries are linked with high energy respectively high relative impact speed.
Otte, Dietmar
Thoracic Spine Extension Injuries in Occupants with Pre-Existing Conditions during Rear-End Collisions2019-01-12224/2/2019
Certain ankylosing spondyloarthropathies such as ankylosing spondylitis (AS) or diffuse idiopathic skeletal hyperostosis (DISH) can substantially alter clinicopathologic spine biomechanics as well as injury mechanisms in rear-end motor vehicle collisions. AS is an inflammatory disease which can lead to structural impairments of the spine secondary to flowing ossification along the spinal column, including ossification across the spinal discs, facet joints, and ligaments, and it has also been associated with diffuse osteoporosis of the spine. DISH is characterized by excess bone formation along the spinal column, encompassing the annulus and forming the thickest and strongest bridging osteophytes over adjacent vertebral bodies at the level of the disc space. In both conditions the spine is mechanically stiffened and generally more kyphotic than a healthy spine. This paper presents a series of case studies in which a front-seat occupant with ankylosing spondyloarthropathy experienced a moderate- or high-speed rear-end collision and sustained a thoracic spine fracture/dislocation, often with spinal cord injuries. Forward acceleration of the occupant by the seat back in each case resulted in straightening of the kyphotic thoracic spine and consequent extension fractures of the pathologically stiff and brittle thoracic spine. This paper illustrates the predisposition of thoracic fracture for this segment of the population with spinal pathologies such as DISH and AS in rear impacts and notes the role that seat back stiffness could play in injury mechanism for these individuals.
Davis, Mathieu, Isaacs, Jessica, Graber, Martin, Fisher, Jacob
Quantification of Sternum Morphomics and Injury Data2019-01-12174/2/2019
Crash safety researchers have an increased concern regarding the decreased thoracic deflection and the contributing injury causation factors among the elderly population. Sternum fractures are categorized as moderate severity injuries, but can have long term effects depending on the fragility and frailty of the occupant. Current research has provided detail on rib morphology, but very little information on sternum morphology, sternum fracture locations, and mechanisms of injury. The objective of this study is two-fold (1) quantify sternum morphology and (2) document sternum fracture locations using computed tomography (CT) scans and crash data. Thoracic CT scans from the University of Michigan Hospital database were used to measure thoracic depth, manubriosternal joint, sternum thickness and bone density. The sternum fracture locations and descriptions were extracted from 63 International Center for Automotive Medicine (ICAM) crash cases, of which 22 cases had corresponding CT scans. The University of Michigan Internal Review Board (HUM00043599 and HUM00041441) approved the use of crash cases and CT scan data. The sternum morphomics data showed the thoracic depth increased, except for the 60-74-year-old age group. The average sternum thickness was greater in the older age groups. The sternum bone density decreased from youngest to oldest age groups. The angle between the manubrium and the sternum body decreased by 5.6° between the youngest and oldest age groups. The frequency of sternum fractures increased after age 45. Fractures were most frequent in the sternum body. The seat belt webbing was coded as the source of 54% of the sternum fractures.
Bunn, Barbara, Johannson, Suzanne, Kohoyda-Inglis, Carla, Wang, Stewart, Parenteau, Chantal, Holcombe, Sven
CAE Based Head Form Impact Simulations for Development of Vehicle Interiors2019-26-02371/9/2019
The interior components of a passenger vehicle are designed to provide comfort and safety to its occupants. In the event of accident, vehicle interiors are primary source of injuries when occupants interact with them. Vehicle interiors consists of Instrument panel (IP), center console, seats and controls in front of seating position etc. Severity of the injuries depends on the energy dissipating characteristics, profiles, projections of different interior components. These are assessed by ECE R21 and IS12553 head form impact tests. To evaluate the Head form impact performance on Interior components, Computer Aided Engineering (CAE) simulations are extensively used during the vehicle development. In order to predict failure of plastic components and snap joints which might lead to expose sharp edges, it is critical to model plastic material and snap joint. Vehicle interiors are certified for head form impact requirements based on physical testing where dashboard samples from productions tools are used. At this stage of development, if any failure occurs then changes in interior design becomes very expensive and time consuming. To avoid this situation, CAE based failure predictions and injury performance evaluations are done during initial design phase of product development when changes are easily implemented without time and cost penalties. This paper describes the development of vehicle interior using CAE based head form impact simulations and predicting the failures like sharp edges exposure, structural integrity or joint failures. For accurate prediction of these failures in CAE based vehicle interior development, plastic material characterization and snap joint failure characterization are done.
Suryawanshi, Yuvraj, Joshi, Kedar, Lambate, Sachin, Jadhav, Vilas
Ground Landing Mechanisms in Vehicle-To-Pedestrian Impacts Based on Accident Video Records2018-01-10444/3/2018
Accident data have shown that the pedestrian injuries resulting from contact with the ground are serious and may even be worse than the injuries resulting from the primary contact with the vehicle. The landing mechanisms, including the pedestrian trajectory and subsequent sequential body region contacts to the ground, are the basis for understanding the ground impact injuries of pedestrians. However, the landing mechanisms of pedestrian are too complicated to be categorized via investigation of the collision information after an accident has occurred. Nowadays, pedestrian kinematics after vehicle impacts can be observed from the accident videos that have been recorded by road monitoring and driver recorders. This study was aimed at investigating the pedestrian landing mechanisms and analyzing the influencing factors. In the current study, 134 pedestrian cases (involving 136 pedestrians) were selected from the internet, and 13 types of landing mechanisms were classified according to the fall kinematics and landing posture. Our results show that pedestrians who were thrown forward and hit the ground without a clear rotational tendency (ground landing mechanism II) accounted for the highest frequency, 49.3% in all cases. The landing mechanisms of pedestrians were affected by impact velocities and kinematic trajectories during vehicle impacts. The results of this study can benefit the development of vehicle safety systems that reduce pedestrian ground impact injuries.
Li, Quan, Han, Yong, Mizuno, Koji
Synthetic Hydrogels Deliver Cells to Repair Intestinal InjuriesTBMG-2797512/1/2017
By combining engineered polymeric materials known as hydrogels with complex intestinal tissue known as organoids— made from human pluripotent stem cells — researchers have taken an important step toward creating a new technology for controlling the growth of these organoids and using them for treating wounds in the gut that can be caused by disorders such as inflammatory bowel disease (IBD).
Senior Drivers, Bicyclists and Pedestrian Behavior Related with Traffic Accidents and Injuries2017-01-13973/28/2017
While accident data show a decreasing number of fatalities and serious injuries on European Union (EU) roads, recent data from ERSO (European Road Safety Observatory) show an increasing proportion of elderly in the fatality statistics. Due to the continuous increase of life expectancy in Europe and other highly-developed countries, the elderly make up a higher number of drivers and other road users such as bicyclists and pedestrians whose mobility needs and habits have been changing over recent years. Moreover, due to their greater vulnerability, the elderly are more likely to be seriously injured in any given accident than younger people. With the goal of improving the safety mobility of the elderly, the SENIORS Project, funded by the European Commission, is investigating and assessing the injury reduction that can be achieved through innovative tools and safety systems. The first step was to develop the required understanding of accident scenarios, injury mechanisms and risks and to implement these findings in the test tool and test assessment procedures. To this end, accident databases were studied and compared regarding the more critical accident scenarios involving the elderly and their injuries as well as their behavior and the transport modes that represent higher risk. This paper presents a novel statistical study of the accident database in Spain and provides an overview of the main accident situations involving elderly drivers, bicyclists or pedestrians as well as the most typical causes of injury and its severity. Moreover, the in-depth analysis of scenarios, actions and law violations carried out makes it possible to identify the travelling behavior of the elderly. Differences between ages and gender were also identified. The conclusions match with general beliefs and with literature information. Finally a general comparison with results from other countries was done.
Fornells, Alba, Parera, Núria, Ferrer, Adria, Fiorentino, Anita
Recommendation for Acceptable Operating Parameters of Heated Automobile Seats in Order to Mitigate Occupant InjuryJ3047_201601 (Historical)1/6/2016
This recommended practice will promote a temperature and duration guideline that mitigates the risk of thermal injuries to the heated seat user. In addition, recommendations are established to indicate to the user when the heater is operating, and warnings that should be included in the vehicle literature.
Heated Seats Standards Committee
Field-based Assessments of Various AIS2+ Head Risk Curves for Frontal Impact2015-01-14374/14/2015
In the present study, various risk curves for moderate-to-fatal head injury (AIS2+) were theoretically assessed by comparing model-based injury rates with field-based injury rates. This was accomplished by applying the risk curves in corresponding field models. The resulting injury rates were considered from two perspectives: aggregate (0-56 kph events) and point-estimate (higher-speed, barrier-like events). Four risk curves were studied: a HIC15-based curve from Mertz et al. (1997), a BRIC-based curve from Takhounts et al. (2011), a BrIC-based curve from Takhounts et al. (2013) and a Concussion-Correlate-based curve from Rowson et al. (2013). The field modeling pertained to adult drivers in 11-1 o'clock, towaway, full-engagement frontal crashes in the National Automotive Sampling System (NASS, calendar years = 1993-2012), and the model-year range of the passenger vehicles was 1985-2010. The attendant inhomogeneity of the restraint systems was approximated by four representative systems. Prior to the field modeling, base models were developed and validated to acceptable levels. Specifically, there were seven assessments of head-impact tests (avg PctDiff = 5.2%) and nine assessments of representative restraint-system models relative to fleet-wide tests (avg PctDiff = 5.0% relative to fleet medians). Subsequently, 36 comparisons were conducted via the field modeling relative to NASS (i.e., four curves and nine aggregate/point assessments). On average, the Concussion-Correlate-based curve demonstrated the best fidelity from the aggregate perspective (+7% difference), with the following rank ordering: Concussion Correlate, HIC15, BRIC, and BrIC. As for the point-estimate perspective, the HIC15 curve demonstrated the best fidelity (−26% difference), rank ordered as HIC15, Concussion Correlate, BRIC, and BrIC. The data underlying these results indicated that more study is needed to improve the fidelity of curve-based risk estimation.
Laituri, Tony R., El-Jawahri, Raed E., Henry, Scott, Sullivan, Kaye
Comparison of Mobile Aircrew Restraint Strategies in a Full-Scale CH-46 Airframe Crash TestF-0070-2014-94795/20/2014
A full-scale crash test of a USMC CH-46 helicopter airframe was conducted at NASA-Langley Research Center. One of the internal experiments was an assessment of mobile aircrew restraint concepts. Two Hybrid III Pedestrian Anthropomorphic Test Devices (ATD's) were positioned in a standing position, just aft of the crew door. On the left side, a traditional gunner's belt was employed. On the right side, the Mobile Aircrew Restraint System (MARS) was employed with the Aircrew Endurance vest. The motivation behind this experiment was based on several mishap-based injuries of mobile aircrew that were using traditional gunner's belts. However, correlation of presumed injury causes with equipment deficiencies was difficult because of a near total void of mobile aircrew restraint testing data in a system-level environment. For the condition tested, the measured results for the two ATD's indicated a dramatic reduction in injury probability when employing the MARS. In contrast, the ATD equipped with the gunner's belt experienced accelerations and forces that could generally be considered lethal.
Bark, Lindley
Finite Element Study of Post-crash Kinematics and Injury Mechanisms of Bus-Pedestrian Collisions2014-01-20313/24/2014
Road traffic accidents are major cause of fatalities and losing property. In many big cities, many common fatal accidents are involved buses and pedestrians. In order to increase safety for pedestrians, it is necessary to understand pedestrian-vehicle collisions and injury mechanisms. Injury characteristics and mechanisms depend on post-crash kinematics. It is obvious that post-crash kinematics resulting from passenger car-pedestrian crash is much different from bus-pedestrian crash. Bus-pedestrian collision study can be done through costly full scale crash tests. An alternative approach to these actual tests is finite element simulations which have been widely employed for vehicle components design and optimisation. This paper has addressed the development of bus-to-pedestrian collision finite element model. The model has been used to study influences of impact speed and impact angle on post-crash kinematics and injury mechanisms of a pedestrian. Relations between the injury risk, the impact speeds and the impact angles have been discussed. The analysis information will assist better design of the bus front structure.
Charoenthong, Sujeepapha, Carmai, Julaluk
Reconstruction Tests Design to Support the Correlation of Real Injuries with Dummy Readings2012-36-045610/2/2012
From the many sub-tasks of the four study areas of the EC CASPER project, this paper presents the following point: • Child protection improvements as a result of accident reconstructions and development of injury risk curves. The first step in achieving this aim was to collect real world in-depth road accident data involving restrained children, with injuries systematically coded using the AIS (Abbreviated Injury Scale, AAAM 1998). This activity identified the priority body regions to be protected (therefore requiring injury risk curves) and provided cases to be reconstructed in full scale crash tests. In such reconstructions dummy readings were correlated with the occupants' injuries in the real accident to develop injury risk curves (after validation checks for crash severity and dummy kinematics). At the same time, online and field surveys were carried out to identify the safety of children when travelling in cars. These sociological studies provided information to identify the misuses of the Child Restraint Systems (CRS), resulting in new dynamic testing programs for their evaluation. The integration of these two activities resulted in the development of the criteria for selecting accident cases that would provide valuable information for the injury risk curves and which were technically feasible in crash testing laboratories. In order to select accident cases that would provide valuable information for the injury risk curves - a good spread across the whole spectrum of the AIS injury assessment (AIS1 - AIS6) - a case selection criteria was used that favoured more severe accidents in terms of injury severity or low injury severity accidents with high crash severities. The cases put forward for reconstruction had to be technically feasible in crash testing laboratories. Additionally, the signals captured from the new abdominal sensors, developed in the project, provided information for the injuries prediction in that area of the body. The present document was written before the end of the project so some of the references, such as results and conclusions are preliminary. However, it was possible to identify the child safety protection problems, based on the results of the sociological survey. The final results for the improvement of the Injury Risk Curves will be known when the final reports and models are released.
Longton, Alejandro, Lesire, Philippe, Johannsen, Heiko, Beillas, Philippe, Fiorentino, Anita, Kirk, Alan, Ferrer, Adria
An Investigation of Injury Factors Concerning Drivers in Vehicles Involved in Small-Overlap Frontal Crashes2012-01-05994/16/2012
The causes of injuries suffered by drivers in “small-overlap frontal crashes” (SOFC) were examined. These crashes were defined as ones in which vehicles are loaded outside their longitudinal side members. SOFC accident data sets stored in the National Automotive Sampling System-Crashworthiness Data System (NASS-CDS) database were investigated. Percentages of cases sustaining injury to each body region of drivers were calculated, and the differences between the percentages of injury by body region were examined. To investigate the injury mechanisms, SOFC tests with two types of rigid barrier were then conducted. Injury values in each body region were analyzed to validate the reproducibility of SOFC test as a relevant test.
Kikuchi, Takahiro, Nakao, Tomoyuki, Watanabe, Taisuke, Saeki, Hidetsugu, Okabe, Tomosaburo
Injury Predictors for Traumatic Axonal Injury in a Rodent Head Impact Acceleration Model2011-22-000211/7/2011
A modified Marmarou impact acceleration injury model was developed to study the kinematics of the rat head to quantify traumatic axonal injury (TAI) in the corpus callosum (CC) and brainstem pyramidal tract (Py), to determine injury predictors and to establish injury thresholds for severe TAI. Thirty-one anesthetized male Sprague-Dawley rats (392 ± 13 grams) were impacted using a modified impact acceleration injury device from 2.25 m and 1.25 m heights. Beta-amyloid precursor protein (β-APP) immunocytochemistry was used to assess and quantify axonal changes in CC and Py. Over 600 injury maps in CC and Py were constructed in the 31 impacted rats. TAI distribution along the rostro-caudal direction in CC and Py was determined. Linear and angular responses of the rat head were monitored and measured in vivo with an attached accelerometer and angular rate sensor, and were correlated to TAI data. Logistic regression analysis suggested that the occurrence of severe TAI in CC was best predicted by average linear acceleration, followed by power and time to surface righting. The combination of average linear acceleration and time to surface righting showed an improved predictive result. In Py, severe TAI was best predicted by time to surface righting, followed by peak and average angular velocity. When both CC and Py were combined, power was the best predictor, and the combined average linear acceleration and average angular velocity was also found to have good injury predictive ability. Receiver operator characteristic curves were used to assess the predictive power of individual and paired injury predictors. TAI tolerance curves were also proposed in this study.
Li, Yan, Zhang, Liying, Kallakuri, Srinivasu, Zhou, Runzhou, Cavanaugh, John M.
Development of a Duration Threshold for Modulating Evoked Neuronal Responses After Nerve Root Compression Injury2011-22-000111/7/2011
Cervical nerve roots are susceptible to compression injuries of various durations. The duration of an applied compression has been shown to contribute to both the onset of persistent pain and also the degree of spinal cellular and molecular responses related to nociception. This study investigated the relationship between peripherally evoked activity in spinal cord neurons during a root compression and the resulting development of axonal damage. Electrically evoked spikes were measured in the spinal cord as a function of time during and after (post-compression) a 15 minute compression of the C7 nerve root. Compression to the root significantly (p=0.035) reduced the number of spikes that were evoked over time relative to sham. The critical time for compression to maximally reduce evoked spikes was 6.6±3.0 minutes. A second study measured the post-compression evoked neuronal activity following compression applied for a shorter, sub-threshold time (three minutes). Ten minutes after compression was removed, the discharge rate remained significantly (p=0.018) less than baseline by 58±25% relative to sham after the 15 minute compression, but returned to within 3±33% of baseline after the three minute compression. Axonal damage was evident in the nerve root at day seven after nerve root compression only after a 15 minute compression. These studies demonstrate that even a transient mechanical insult to the nerve root is sufficient to induce sustained neuronal dysfunction and axonal pathology associated with pain, and results provide support that such minor neural tissue traumas can actually induce long-lasting functional deficits.
Nicholson, Kristen J., Quindlen, Julia C., Winkelstein, Beth A.
Combat Casualty Care Educational Program Developed for U.S. Armed ForcesTBMG-104577/1/2011
With American troops leaving Iraq and military efforts continuing in Afghanistan, educators at the University of California at Los Angeles (UCLA) have helped develop a first-of-its-kind educational program to train U.S. armed forces medical personnel in critical combat casualty care. The program will not only help advance military care, the program's developers say, but civilian care as well.
Nerve Level Traumatic Brain Injury in in Vivo/in Vitro Experiments2010-22-001011/3/2010
The number of traffic deaths in Japan was 4,914 in 2009. Since the head was the most common site of injury in traffic accidents (2,302, 47%), traumatic brain injury causes the fatalities in these accidents. The aim of the present study was to quantify micro injuries in the animal brain for gaining insight and understanding of the human brain injury tolerance. Using porcine brain matter, in vitro stress relaxation experiments and in vivo impact experiments were conducted. In both experiments, the distribution of the damage ratio of the transverse to longitudinal length of cells, hereafter, referred to as an aspect ratio, in the brain matter under loading was examined. In the in vitro stress relaxation experiments, specimens were compressed vertically with a compression velocity of 1 mm/s, and the displacement was held for 140 sec when the compression strain reached the target strain. In the experiments, there were five categories of compression strain: 10, 20, 30, 40, and 50 percent. Regarding the aspect ratio of the cell body, it was 1.5 or less in a no-load condition. On the other hand, it was observed to be greater than 1.5 in the results from the experiments if the compression strain was 30% or more. The results from the experiments show that a compression strain between 20% and 30% corresponds to the threshold for the extremely deformed cell at the micro level. In the in vivo impact experiments, pigs in an unconscious state were exposed through craniotomy, and their exposed brains were hit with a ram at a low speed of 3.3 m/s and a high speed of 7.2 m/s, respectively. It was revealed that the number of cells in which the aspect ratio was greater than 1.5 increased if the impact is provided under the high speed. At the same time, the results indicated that cell deformation was dependent on the ram velocity in the brain matter. Thus, the compression strain on the entire brain from the direction of the force applied to the brain may be one criterion for assessment of brain damage.
Matsui, Yasuhiro, Nishimoto, Tetsuya
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
Analysis of Shoulder Ligament Injury Potential in Automotive Rear-End Impacts2009-01-12034/20/2009
The potential for injury to the acromioclavicular (AC) and coracoclavicluar (CC) ligaments as potential sequelae of rear-end collisions is examined. In the current study, rear-end impact data from four crash tests were analyzed to quantify and bound forces applied to the shoulder of the Hybrid III 50th percentile male occupant seated in the target vehicle. Two potential scenarios for AC and CC ligament loading were examined: 1) relative motion between the clavicle and shoulder due to belt loading on the shoulder and torso, and 2) compression of the humerus into the glenoid fossa due to locked arms on the steering wheel. Assumptions were made for the shoulder load calculations to obtain a conservative upper bound of loads that could be applied to the AC and CC ligaments. With the target vehicle at rest, the bullet vehicle speeds were 5, 10, 15, and 20 mph, yielding target vehicle changes in velocity (delta-V) of 3.9, 6.5, 8.9 and 12.2 mph. In all tests, the occupant moved initially rearward relative to the vehicle until accelerated forward by forces transmitted through the seat. For the 50th percentile male, the AC and CC ligament forces for Scenarios 1 and 2 ranged from 38–90 N and 71–462 N. Force values calculated were less than reported force at failure of the AC and CC ligament. The forces and occupant kinematics associated with rear-end, low-speed collisions are not likely to result in AC or CC ligament injury.
Lucas, Scott, Ianuzzi, Allyson, McGowan, Joseph, Toosi, Kevin
Comparison of Impact Configurations for the Development of a Crash-Test Standard in Motorcycle Safety Using a Human Model2008-01-19006/17/2008
The problem of injuries to motorcyclists caused by impacts on roadside barriers has been a research issue for more than two decades. Within the European research project APROSYS SP4 “Motorcycle Accidents”, a European crash test standard for the assessment of impact performance of roadside barriers with respect to injury risks will be proposed. The focus of this work is on the sliding impact after the separation of the rider from the powered two-wheeler. The human model for crash simulation HUMOS2 was applied to gain insights into injury mechanisms. It was found that an impact configuration specifically aiming at the loading of the thorax does not need to be included in a test standard. As there are no crash-test dummies available that have specifically been developed and validated for this application, the use of a numerical human body model is the only way to gain insight into the described problem without conducting PMHS tests.
Peldschus, Steffen, Schuller, Erich, Garcia, David, Pérez-Magallón, Begoña, Mansilla, Alberto
MADYMO Model to Assess Lumbar Spine Loading during Activities of Daily Living2008-01-19106/17/2008
Determining injury causation and/or developing injury thresholds is important, specifically in the lumbar spine during minor accidents. Much work has been done to study cervical spine behavior, however, there is a lack of data on injury thresholds of the lumbar spine and on lumbar exposure during these minor events. A MADYMO model was developed to quantify the lumbar loads and accelerations experienced when dropping down onto a surface into a seated position. The model was validated using data collected during tests involving an instrumented Hybrid III dummy. This work shows that MADYMO models can be used to predict the lumbar spine's exposure during common everyday activities.
Freyder, Dawn R., Peterman, Elaine K., Moor, Douglas R., Ratliff, Adam R., Wiechel, John F.
Region-Specific Tolerance Criteria for the Living Brain2007-22-000510/29/2007
Computational models of traumatic brain injury (TBI) can predict injury-induced brain deformation. However, predicting the biological consequences (i.e. cell death or dysfunction) of induced brain deformation requires tolerance criteria. Here, we present a tolerance criterion for the cortex which exhibits important differences from that of the hippocampus. Organotypic slice cultures of the rat cortex, which maintain tissue architecture and cell content consistent with that in vivo, were mechanically injured with an in vitro model described previously. Cultures were stretched equibiaxially up to 0.35 Lagrangian strain at strain rates up to 50 s−1. Cell death was quantified at 1, 2, 3, and 4 days following injury. Statistical analysis (repeated measures ANOVA) showed that all three factors (Strain, Strain Rate, and Time post-injury) significantly affected cell death. An equation describing cell death as a function of the significant parameters was then fit to the data. Compared to the hippocampus, the cortex was less vulnerable to stretch-induced injury and demonstrated a strain threshold below 0.20. Strain rate was also a significant factor for cortical but not hippocampal cell death. Cortical cell death began at an earlier time point than in the hippocampus, with cell death evident at 1 day post-injury versus 3 days in the hippocampus. In conclusion, different regions of the brain respond differently to identical mechanical stimuli, and this difference should be incorporated into finite element models of TBI if they are to more accurately predict in vivo consequences of TBI.
Elkin, Benjamin S., Morrison, Barclay
Influence of Impact Speed on Head and Brain Injury Outcome in Vulnerable Road User Impacts to the Car Hood2007-22-000710/29/2007
EuroNCAP and regulations in Europe and Japan evaluate the pedestrian protection performance of cars. The test methods are similar and they all have requirements for the passive protection of the hood area at a pedestrian to car impact speed of 40 km/h. In Europe, a proposal for a second phase of the regulation mandates a brake-assist system along with passive requirements. The system assists the driver in optimizing the braking performance during panic braking, resulting in activation only when the driver brakes sufficiently. In a European study this was estimated to occur in about 50% of pedestrian accidents. A future system for brake assistance will likely include automatic braking, in response to a pre-crash sensor, to avoid or mitigate injuries of vulnerable road users. An important question is whether these systems will provide sufficient protection, or if a parallel, passive pedestrian protection system will be necessary. This study investigated the influence of impact speed on head and brain injury risk, in impacts to the car hood. One car model was chosen and a rigid adjustable plate was mounted under the hood. Free-flying headform impacts were carried out at 20 and 30 km/h head impact velocities at different under-hood distances, 20 to 100 mm; and were compared to earlier tests at 40 km/h. The EEVC WG17 adult pedestrian headform was used for non-rotating tests and a Hybrid III adult 50th percentile head was used for rotational tests where linear and rotational acceleration was measured. Data from the rotational tests was used as input to a validated finite element model of the human head, the Wayne State University Head Injury Model (WSUHIM). The model was utilized to assess brain injury risk and potential injury mechanism in a pedestrian-hood impact. Although this study showed that it was not necessarily true that a lower HIC value reduced the risk for brain injury, it appeared, for the tested car model, under-hood distances of 60 mm in 20 km/h and 80 mm in 30 km/h reduced head injury values for both skull fractures and brain injuries. An earlier study showed that the corresponding value for a test speed of 40 km/h is 100 mm. A 10 km/h reduction in head impact velocity, as in automatic braking, allowed 20 mm less under-hood clearance with maintained head protection of the vulnerable road user.
Fredriksson, Rikard, Zhang, Liying, Boström, Ola, Yang, King
Using Forefoot Acceleration to Predict Forefoot Trauma in Frontal Crashes2007-01-07044/16/2007
A common injury type among foot and ankle injury is the Lisfranc trauma, or injury to the forefoot. The Lisfranc injury indicates abnormal alignment of the tarsal-metatarsal joints with the loss of their normal spatial relationships. In 2003, Smith completed a laboratory study of this injury mechanism at Wayne State University [1, 2]. He found Lisfranc trauma was correlated with impact force to the forefoot. He proposed a probability of injury function that is based on the applied force to the forefoot. This study examined the instrumentation in the foot of the dummies in the USA New Car Assessment Program (NCAP) and Insurance Institute of Highway Safety (IIHS) frontal crashes. Nineteen different passenger vehicles representing four different vehicle classes were selected based mostly on a large presence in the USA vehicle fleet. Both NCAP and IIHS crashed these nineteen makes and models. The NCAP dummies were instrumented with an accelerometer at the forefoot that captured the acceleration in the z-direction. The IIHS dummies had a bi-axial accelerometer at the ankle, but not at the forefoot. For the years 1995 - 2005, the real world crash data in the National Automotive Sampling System/ Crashworthiness Data System (NASS/CDS) were examined. The number of female drivers who sustained AIS 2+ level for foot and ankle injuries is higher than the number of male drivers.
Buyuk, Murat, Ozkan, Demet, Morgan, Richard M., Digges, Kennerly H.
Wavelet-based Non-parametric Estimation of Injury Risk Functions2007-01-11564/16/2007
An injury risk function defines the probability of an injury as a function of certain measurable or known predictors. In this paper, wavelet analysis is employed for the non-parametric estimation of injury risk functions. After a brief introduction of the wavelet theory, the representation of density function by wavelet series is given. A procedure for the estimation of density function is described. The risk function estimation for right-censored data is investigated by introducing hazard rate function and its wavelet estimator. The use of the developed method is illustrated in a case study, where two sets of data are used: simulation data with known distribution and censoring information, and thoracic impact testing data, which are assumed to be right- censored. Comparisons are made between the wavelet-based approach and the empirical Kaplan-Meier non-parametric method.
Cheng, Zhiqing, Rizer, Annette L., Pellettiere, Joseph A.
New Method of Vehicle Inspection for Incompatible Crashes2007-01-11844/16/2007
This paper creates a worksheet to thoroughly document vehicle damage during an incompatible vehicle-to-vehicle frontal crash. This data form serves as a supplement to the current and already established NASS inspection forms. It will assist biomechanics research by determining the extent by which incompatibility caused or changed occupants' injuries through structural analysis of the vehicles. This study identifies deficiencies in the current NASS inspection system for compatibility, and develops new measurable parameters to document the crash and associate injury to it.
Alonso, Brian, Stratton, James, Digges, Kennerly
Technical Parameters for Determination of Impact Speed for Motorcycle Accidents and the Importance of Relative Speed on Injury Severity2006-01-15624/3/2006
The value of on scene in-depth accident research studies has been recognized internationally and many countries worldwide have such teams. Since such detailed information is essential for improving the safety of cars, a strong collaboration with automakers developed. This resulted in Germany in a joint project between FAT (Forschungsvereinigung Automobiltechnik -Automotive Industry Research Association) and BASt (Bundesanstalt für Straßenwesen -Federal Road Research Institute). The project started on July 1999 and is called “GIDAS” (German In-Depth Investigation Accident Study). The paper is describing the methodology of this project with statistically orientated procedure of data sampling on the one hand and will give an overview of procedures for the determination of impact speed on the basis of an on scene investigation on the other hand. Crash information e.g. driving and collision speed have to be determined from tire marks and all artefacts at the scene as well as from the final position of vehicles. Different calculations are used by experts, momentum analysis and energy balance. Information on final position of vehicles, deformation pattern on vehicles, tire marks and artefacts found on the road like braking and sliding marks, throwing distances of the motorbike rider and the cyclists supplies possibilities for reconstruction of the movement of the human body and determination of collision speed. The paper describes the possibilities of the use of these parameters for reconstruction and will show the injury pattern for motorcyclists in the German traffic accident situation, based on the GIDAS sample in statistical representative manner.
Otte, D.
Neural Response of Cervical Facet Joint Capsule to Stretch: A Study of Whiplash Pain Mechanism2005-22-000311/9/2005
Cervical facet joints are implicated as a major source of pain after whiplash injury. The purpose of this study was to investigate the proposed capsule strain injury mechanism of whiplash pain using neurophysiologic methods. Strain thresholds, threshold distribution, saturation strains and afterdischarge responses of capsule neural receptors were characterized in vivo. Goat C5-C6 facet joint capsules were used to identify and characterize capsule receptors in response to controlled uniaxial stretch by recording C6 dorsal rootlet nerve discharge. The joints were stretched at 0.5 mm/sec in a series of tests with 2 mm increments until the capsule ruptured. Ninety-two identified units were responsive to physiologic or noxious stretch while 28 were silent receptors. Among the 50 characterized responsive units, 42 showed low strain thresholds at 10.2±4.6% while 8 had high strain thresholds at 47.2±9.6%. Further, 35 of the 42 low-threshold units displayed discharge saturation at various strains (44.2±16.7%). A significant finding was that twelve low-threshold units exhibited afterdischarge for greater than 30 sec after stretch release at 36.6±12.5% strains, and displayed longer-lasting afterdischarge (greater than 4 min) at higher strains (39.0±14.4%) with significant difference (p = 0.019) in strains. Two high-threshold units had afterdischarges for greater than 30 sec or 4 min at 50.3±5.9% and 57.7±10.6% strains, respectively. In addition, the spatial distribution of the 42 low-threshold receptors demonstrated that the receptors on the joint gap were more strain-sensitive, with significantly lower strain thresholds compared to the rostral and caudal regions. No significant difference in strain threshold was observed in the medial-lateral direction. When compared to the reported strains that facet joint capsules experienced in whiplash (35–60%) and the reported capsule subfailure strains (35–67%), the low strain thresholds are substantially lower whereas the high thresholds and afterdischarge strains are within that range. Thus, low threshold units appear to signal proprioception within the physiologic range. High threshold units likely signal nociception (pain sensation) while afterdischarge may signal capsule strain injury and contribute to persistent pain.
Lu, Ying, Chen, Chaoyang, Kallakuri, Srinivasu, Patwardhan, Ajit, Cavanaugh, John M.
Analysis of Finite Element Models for Head Injury Investigation: Reconstruction of Four Real-World Impacts2005-22-000111/9/2005
Previous studies have shown that both excessive linear and rotational accelerations are the cause of head injuries. Although the head injury criterion has been beneficial as an indicator of head injury risk, it only considers linear acceleration, so there is a need to consider both types of motion in future safety standards. Advanced models of the head/brain complex have recently been developed to gain a better understanding of head injury biomechanics. While these models have been verified against laboratory experimental data, there is a lack of suitable real-world data available for validation. Hence, using two computer models of the head/brain, the objective of the current study was to reconstruct four real-world crashes with known head injury outcomes in a full-vehicle crash laboratory, simulate head/brain responses using kinematics obtained during these reconstructions, and to compare the results predicted by the models against the actual injuries sustained by the occupant. Cases where the occupant sustained no head injuries (AIS 0) and head injuries of severity AIS 4, AIS 5, and multiple head injuries were selected. Data collected from a 9-accelerometer skull were input into the Wayne State University Head Injury Model (WSUHIM) and the NHTSA Simulated Injury Monitor (SIMon). The results demonstrated that both models were able to predict varying injury severities consistent with the difference in AIS injury levels in the real-world cases. The WSUHIM predicted a slightly higher injury threshold than the SIMon, probably due to the finer mesh and different software used for the simulations, and could also determine regions of the brain which had been injured. With further validation, finite element models can be used to establish an injury criterion for each type of brain injury in the future.
Franklyn, Melanie, Fildes, Brian, Zhang, Liying, Yang, King, Sparke, Laurie
Injury Tolerance and Response of the Ankle Joint in Dynamic Dorsiflexion2004-22-000111/1/2004
Forced dorsiflexion in frontal vehicle crashes is considered a common cause of injury to the ankle joint. Although a few studies have been published on the dynamic fracture tolerance of the ankle in dorsiflexion, this work reexamines the topic with increased statistical power, adds an evaluation of articular cartilage injury, and utilizes methods to detect the true time of fracture. The objective of this study was to measure the response and injury tolerance of the human ankle in a loading condition similar to that found in a vehicle crash with toepan intrusion. A test fixture was constructed to apply forefoot impacts to twenty cadaveric lower limbs, that were anatomically intact distal to the femur mid-diaphysis. Specimen instrumentation included implanted tibial and fibular load cells, accelerometers, angular rate sensors, and an acoustic sensor. Following the tests, specimens were radiographed and dissected to determine the extent of injury. Eleven of the twenty specimens sustained fracture of the ankle joint. Fractures of the medial malleolus were the most common, while two specimens sustained bimalleolar fractures, and two a talar neck fracture. Other injuries included ligament tears, osteochondral fractures, and cartilage abrasions. Analysis of the acoustic emission indicated that fracture did not always occur at the peak ankle moment. Based on the results of this study, an ankle joint moment of 59 N-m represents a 25% risk of ankle fracture in dorsiflexion for a 50th percentile male. When applied to the Thor-Lx dummy, the 25% risk of injury occurs at 36° of dorsiflexion as measured by the ankle potentiometer.
Rudd, Rodney, Crandall, Jeff, Millington, Steven, Hurwitz, Shepard, Höglund, Niklas
Virtual Testing of Driver OOP Scenarios: Effect of Modeling Detail on Injury Response2004-01-16293/8/2004
This study investigates the relevance of certain parameters for virtual testing of the driver's side OOP problem and attempts to answer the following questions: Which level of detail is needed in the airbag models to assess occupants' injury values for OOP scenarios? What is the influence of the airbag cover on the occupant response for OOP situations and how to accurately model the airbag cover? Are current dummy models suitable to assess the localized human injuries and/or is it beneficial to include human models for injury assessment? The combined multibody-FE code MADYMO was used. A virtual set-up of a folded driver airbag including cover, steering wheel and a simple seat forms the base model. Occupants were positioned according to the two OOP driver positions defined in FMVSS 208, i.e. chin on module to maximize neck injury risk and chest on module to maximize chest injury risk. The 5th percentile Hybrid III dummy model as well as the 5th percentile human model were used and different airbag inflation and cover modeling techniques were investigated. Attention was focussed on analyses of the injury values obtained from the simulations of the different situations (with / without cover, use of gasflow, human / dummy model). From this study, it is concluded that it is important to take into account the geometrical effects of the airbag cover on airbag deployment and hence injury generation in OOP simulations. Adding a gasflow description to the airbag deployment simulation resulted in differences in the early deployment phase. If the dummy's injuries are determined in this phase (dependent of scenario), gasflow contributes to improved airbag modeling at the cost of higher CPU times. From the human model simulations, it is concluded that for this specific scenario, using dummy models could lead to underestimation of human injuries in the chest region, in contrast to overestimation of the head acceleration and the neck loads in the rebound phase. Therefore, human models could provide additional value compared to dummy models.
Bosch-Rekveldt, M.G.C., van Hoof, J.F.A.M.
Use of Throw Distances of Pedestrians and Bicyclists as Part of a Scientific Accident Reconstruction Method2004-01-12163/8/2004
Crash information, e.g. driving and impact speed, have to be determined from traces on the scene, as well as from examination of deformation patterns in order to assess the impact condition and the movement trajectories of the impacted body of bicyclists and pedestrians after car collision. Experts use the following information to calculate speed: Information on final position of vehicles, deformation pattern on vehicles, traces found on the road, such as braking and sliding marks, throw distances of pedestrians and cyclists and injury pattern, all these issues are given possibilities for reconstruction of the movement of the human body. While in car to car crashes the speed calculation is based on the momentum analysis and on energy balance hypothesis of classical physics, the calculation for pedestrian and bicycle accidents have to be based on traces only. The paper describes the possibilities of the use of throw distance as a reconstruction method. The paper also discusses the tolerance fields, compared to the results of crash tests. Throw distances and impact kinematics are shown for pedestrians and bicyclists at low and high impact speeds up to 100 km/h.
Otte, D.
A Tissue Level Tolerance Criterion for Living Brain Developed with an In Vitro Model of Traumatic Mechanical Loading2003-22-000610/27/2003
Traumatic brain injury (TBI) is caused by brain deformations resulting in the pathophysiological activation of cellular cascades which produce delayed cell damage and death. Understanding the consequences of mechanical injuries on living brain tissue continues to be a significant challenge. We have developed a reproducible tissue culture model of TBI which employs organotypic brain slice cultures to study the relationship between mechanical stimuli and the resultant biological response of living brain tissue. The device allows for the independent control of tissue strain (up to 100%) and strain rate (up to 150 s-1) so that tolerance criteria at the tissue level can be developed for the interpretation of computational simulations. The application of texture correlation image analysis algorithms to high speed video of the dynamic deformation allows for the direct calculation of substrate strain and strain rate which was found to be equi-biaxial and independent of radial position. Precisely controlled, mechanical injuries were applied to organotypic hippocampal slice cultures, and resultant cell death was quantified. Cell death was found to be dependent on both strain magnitude and rate and required several days to develop. An immunohistological examination of injured cultures with antibodies to amyloid precursor protein revealed the presence of traumatic axonal injury, suggesting that the model closely replicates in vivo TBI but with advantages gained in vitro. We anticipate that a combined in vitro approach with optical strain mapping will provide a more detailed understanding of the dependence of brain cell injury and death on strain and strain rate.
Morrison, Barclay, Cater, Heather L., Wang, Christopher C-B., Thomas, Fay C., Hung, Clark T., Ateshian, Gerard A., Sundstrom, Lars E.
Tolerance of the Cervical Spine to Eccentric Axial Compression2002-22-002211/11/2002
Cervical spine injury resulting from compressive impact loading is a particularly devastating musculoskeletal injury due to the frequency of neurologic involvement. The objective of this research was to investigate the effect of axial eccentricity on the tolerance of the cervical spine. Two functional spinal unit segments (3 adjacent vertebra and their intervening discs and soft-tissues) were dissected from the lower cervical spine of twenty-four human cadaver cervical spines and randomly assigned to one of three loading groups. The eight specimens were tested to failure in compression, compression-flexion, and compression-extension under displacement control on a high-rate MTS load frame. The resulting six-axis loads were measured and evaluated by injury mechanism (group). Statistically distinct (p < 0.01) injury mechanisms, in terms of measured a eccentricity, were produced by each of the eccentric axial compression inputs (compression-flexion, compression-extension, and compression). The axial force at failure for the compression and compression-extension loading environments were nearly equal and significantly (p < 0.01) larger (4-times) than their counterpart in the compression-flexion group. Failure data were compared with the neck injury criteria (Nij) recently proposed by the NHTSA using the 50th percentile male and 5th percentile female injury reference values. The compression and compression-extension mechanisms produced Nij values near 1.0. The compression-flexion series resulted in significantly lower Nij values at failure (approx. 0.3, p < 0.01). The results of this study provide tolerance data for the cervical spine subjected to different compressive loading environments and may be used to enhance injury reference computations facilitating neck injury prevention.
Carter, Jarrod W., Ku, Grace S., Nuckley, David J., Ching, Randal P.
Biomechanics of Inertial Head-Neck Trauma: Role of Cervical Components2002-01-14453/19/2002
Inertial loading of the head-neck complex occurs in rear impacts wherein the head and neck of the occupant are initially subjected to rearward forces. Epidemiological evidence exists to demonstrate the significance and societal impact of these injuries [4]. From a clinical perspective, trauma secondary to inertial loads belongs to the lower end of the Abbreviated Injury Scale, and no specific diagnostic techniques are available to quantitatively document the injury. Furthermore, identification of the mechanisms of injury and derivation of injury thresholds are limited. In fact, there is a paucity of literature focusing on the reproduction of rear impact-induced neck injuries due to a single-event rear impact. Because the impact acceleration is transmitted to the head from the torso via the cervical column, the components of the human neck play a role in the mechanics of trauma. This paper presents the role of cervical spinal components in the injury and describes their associated mechanisms.
Yoganandan, Narayan, Pintar, Frank A.
Japanese research activity on future side impact test procedures2001-06-01556/4/2001
This paper summarizes a future side impact test procedure based on the Japanese presentation at the recent IHRA Side Impact WG meeting. Under current Japanese regulations, the MDB specifications and test procedures were determined based on a market study more than ten years ago. Thus, they may not reflect current automobile characteristics, the actual accident situation, and crash test results. In this study (1) the vehicle types, velocity of striking and struck vehicles, body injury regions, causes of injuries, etc., are reviewed with reference to the latest Japanese side impact accident data. The occupant percentages for the non-struck-side, rear seat and for female occupants as well as the injury levels were analyzed. (2) To determine the MDB specifications, based on data from passenger car models registered in 1998, the curb mass, geometry and stiffness were examined. (3) For factorial analysis, side impact tests were performed as for real accidents. Issues for future side impact test procedures include protection of the non-struck-side and rear seat occupants, the female occupants and the comparison of the dummy injury severity with or without crabbed angle, along with comparison between EuroSID-1 responses and ES-2 prototype responses. We have conducted full-scale tests in these areas. Based on these results, we present the Japanese view regarding future side impact test procedures.
Yonezawa, Hideki, Harigae, Takeshi, Ezaka, Yukihiro
THE POTENTIAL GAIN TO BE ACHIEVED BY GENERALIZATION OF SEAT BELTS AND AIRBAGS IN TRUCKS2001-06-01936/4/2001
In recent years, throughout Europe, truck manufacturers have developed and installed occupant restraint systems similar to those that have been available in passenger vehicles for a long time. The development of truck seatbelts and steering-wheel mounted airbags is based on occupant safety research, and the need to meet European safety regulations which will come into effect in the near future. This paper aims to evaluate the potential efficiency of a seat belt coupled to an airbag. The study is based on the CEESAR truck accidents database. The sample includes 403 accidents which involved 479 unbelted occupants (all injury level). The injury causation mechanism according to the type and the severity of the crash enable us an effectiveness evaluation based on a supposed 100 % seat belt (and air bag) use rate. The use of seat belts with 3 anchoring points mounted on the seat of trucks (with an airbag) would be effective for 37 % of fatalities, 36 % of seriously injured and 22 % of slightly injured occupants.
Simon, M.C., Botto, P., Page, Y., Paulhet, F.
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.
The Effects of Belt Use and Driver Characteristics on Injury Risk in Frontal Airbag Crashes2001-01-01553/5/2001
From the crash investigation files at the University of Michigan Transportation Research Institute (UMTRI), the crashes involving deployed airbags were reviewed. The total number of deployments is 898 of which 764 are frontal crashes with the principal direction of force (PDF) at 11-1 o’clock. Of the drivers in these frontal crashes 83% were using the belt restraint. Overall, seven of ten drivers have an AIS-0 or 1 level injury as the maximum or highest injury severity level (MAIS). Of the survivors, one in six had a moderate level injury (AIS-2) as their most significant injury and one in nine had an MAIS 3 or greater injury. Fatalities are rare. There is a difference between injury severity frequencies of belted vs. non-belted drivers. Three-quarters of the belted drivers had minor injuries compared to only half of those not belted. A difference was also noted at the AIS-2 level—belted vs. unbelted 14% vs. 23%. Of the belted drivers 10% had an AIS 3–5 injury level compared to 20% of the unbelted. Drivers with AIS 3, 4 or 5 as their highest AIS level, whether belted or not, have the lower extremity as the body region most often injured. Belted drivers have a slightly higher frequency of upper extremity injuries.
Huelke, Donald F.
The Analysis of Accident Data Recorder (ADR) Data in Formula 12000-01-355111/13/2000
The FIA has fitted Accident Data Recorders (ADR) to all Formula1 cars since 1997, and will also fit them to Formula 3000 cars from 2000. Data is recovered, where possible, from all incidents where control of the car has been lost, and the car either impacts another car, or leaves the track and is arrested in a run off area, or impacts a barrier. 3-axis, high-g (±250g) and low-g (±50g) accelerometers, car speed, throttle and steering, the lap marker, and from 2000, yaw rate are recorded. The data is analysed to determine the deceleration on the track and the performance of circuit safety features such as run-off areas and barriers. It is sometimes possible to determine the cause of the loss of control from the data available. The data is used to compute deceleration rates for use in the FIA's Circuit and Safety Analysis System (CSAS) for the assessment of circuit safety features, assess barrier and car impact performance, and provide data for accident reconstruction and modelling. A Severity Index Coefficient (SIC) has been developed to enable impacts to be assessed quickly for their potential to cause head injuries, in order to rate them according to their need for fuller analysis.
Wright, Peter G.
Head Injuries in Vehicle-Pedestrian Impact2000-01-01573/6/2000
In vehicle-pedestrian impacts, the kinematics and severity of pedestrian injuries are affected by vehicle front shapes. Accident analyses and multibody simulations showed that for mini vans the injury risk to the head is higher, while that to the legs is lower than for bonnet-type cars. In mini-van pedestrian impacts, pedestrians ran high risks of a head impact against stiff structures such as windshield frames. When pedestrians are struck by a car with a short hood length, their heads are likely to strike into or around the windshield. The injury risks to the head by such an impact were examined by head form impact tests. The HIC rises from contact with the cowl, windshield frame or A pillar, and it lessens with increasing distance from these structural elements.
Mizuno, Koji, Kajzer, Janusz
Injury Patterns in Side Collisions-A New Look With Reference to Current Test Methods and Injury Criteria99SC0110/10/1999
The UK in-depth data, describing the causation of injuries to casualties in side impacts, was examined for crashes occurring between 1992 and 1998. Slightly more casualties died in side impacts than in frontal crashes, and one-third were seated on the side away from the collision. The collision severity was compared with the European and US legal test procedures and most MAIS 3+ survivors were observed to be in crashes above the severity of the test. The mean delta-V for the fatal group was 48 km/h compared with typically 25 km/h in the test. The most commonly injured body regions of both survivors and fatalities were the head, thorax and lower extremity. The lower extremity was the most frequent site of AIS 2+ injuries of survivors and fractures to the femur and tibia were highlighted, these injuries are not assessed by existing dummies.
Thomas, Pete, Frampton, Richard
The Biomechanics of “Whiplash” in Low Velocity Collisions1999-01-32359/28/1999
Recently, it has been demonstrated experimentally that the so-called “whiplash” response during low velocity rear-end collisions may produce a spontaneously resolving strain injury to muscles of the neck, but that injury to other spinal elements is biomechanically improbable. This paper reviews the results of these studies as a means of addressing the longstanding controversy which surrounds “whiplash” and the claims that the “whiplash” response produces more extensive injuries. It is concluded that there are no objective, experimentally-based scientific data to support the concept that the low-velocity “whiplash” response is capable of producing any injuries beyond those to the cervical musculature.
Howard, Richard P., Harding, Richard M., Krenric, Scott W.
IDENTIFICATION OF HEAD INJURY MECHANISMS ASSOCIATED WITH RECONSTRUCTION OF TRAFFIC ACCIDENTS.1999-13-00029/23/1999
Head injuries often occur in frontal accidents, which are the most frequent type of vehicle collision and causes of injuries. Impact of the head with the steering wheel has been identified as the major source of lesions. In order to mitigate this contact, vehicles available on the European market are now equipped with airbags in addition to the safety belt. Although the inflation of airbags reduces the severity of head injuries in moderate to severe frontal crashes, lesions due to a contact with the steering wheel are still observed in collisions with a severity under the deployment threshold. The analyses of real-life accidents involving airbag deployments show that additional injuries occur in accidents of relatively slight severity. Accordingly, several authors have proposed to increase the deployment threshold of the airbag system for belted occupants. The absence of head injury representative biomechanical criteria prevents an assessment of the risks induced by such a modification. Many studies in the past have demonstrated that the current biomechanical criteria (HIC, SI) are meaningless in real accident situations. Despite the fact that the mechanisms causing head injury were unknown, several injury criteria were proposed which were based on hypothetical theories. To obtain a better understanding of head injury mechanisms and propose new biomechanical criteria in the future, a new research methodology has been developed. The purpose of this study is to present the accident reconstruction methodology so as to provide an estimate of the head loads which are associated with the injuries sustained by the victim. This is however only the preliminary step in the complete analysis. Simulations of head loads with the conditions extracted from the accident reconstruction are the next stage for the identification of head injury mechanisms.
Bertrand, Canaple, Dominique, Cesari, Pascal, Drazetic
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