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Transfer or response equations are important as they provide relationships between the responses of different surrogates under matched, or nearly identical loading conditions. In the present study, transfer equations for different body regions were developed via mathematical modeling. Specifically, validated finite element models of the age-dependent Ford human body models (FHBM) and the mid-sized male Hybrid III (HIII50) were used to generate a set of matched cases (i.e., 192 frontal sled impact cases involving different restraints, impact speeds, severities, and FHBM age). For each impact, two restraint systems were evaluated: a standard three-point belt with and without a single-stage inflator airbag. Regression analyses were subsequently performed on the resulting FHBM- and HIII50-based responses. This approach was used to develop transfer equations for seven body regions: the head, neck, chest, pelvis, femur, tibia, and foot.

Current state-of-the-art vehicles implement pedestrian protection features that rely on pedestrian detection sensors and algorithms to trigger when impacting a pedestrian. During the development phase, the vehicle must “learn” to discriminate pedestrians from the rest of potential impacting objects. Part of the training data used in this process is often obtained in physical tests utilizing legform impactors whose external biofidelity is still to be evaluated. This study uses THUMS as a reference to assess the external biofidelity of the most commonly used impactors (Flex-PLI, PDI-1 and PDI-2). This biofidelity assessment was performed by finite element simulation measuring the bumper beam forces exerted by each surrogate on a sedan and a SUV. The bumper beam was divided in 50 mm sections to capture the force distribution in both vehicles. This study, unlike most of the pedestrian-related literature, examines different impact locations and velocities.

In the present study, transfer equations relating the responses of post-mortem human subjects (PMHS) to the mid-sized male Hybrid III test dummy (HIII50) under matched, or nearly-identical, loading conditions were developed via math modeling. Specifically, validated finite element (FE) models of the Ford Human Body Model (FHBM) and the HIII50 were used to generate sets of matched cases (i.e., 256 frontal impact cases involving different impact speeds, severities, and PMHS age). Regression analyses were subsequently performed on the resulting age-dependent FHBM- and HIII50-based responses. This approach was conducted for five different body regions: head, neck, chest, femur, and tibia. All of the resulting regression equations, correlation coefficients, and response ratios (PHMS relative to HIII50) were consistent with the limited available test-based results.

Injury to the far side occupant has been demonstrated as a significant portion of the total trauma in side impacts. The objective of the study was to determine the response of PMHS in far side impact configurations, with and without generic countermeasures, and compare responses to the WorldSID and THOR dummies. A far side impact buck was designed for a sled test system that included a center console and three-point belt system. The buck allowed for additional options of generic countermeasures including shoulder or thorax plates or an inboard shoulder belt. The entire buck could be mounted on the sled in either a 90-degree (3-o'clock PDOF) or a 60-degree (2-o'clock PDOF) orientation. A total of 18 tests on six PMHS were done to characterize the far side impact environment at both low (11 km/h) and high (30 km/h) velocities. WorldSID and THOR-NT tests were completed in the same configurations to conduct matched-pair comparisons.

Vehicle front-end geometry and stiffness characteristics have been shown to influence pedestrian lower extremity response and injury patterns. The goal of this study is to compare the lower extremity response and injuries of post mortem human surrogates (PMHS) tested in full-scale vehicle-pedestrian impact experiments with a small sedan and a large sport utility vehicle (SUV). The pelves and lower limbs of six PMHS were instrumented with six-degree-of-freedom instrumentation packages. The PMHS were then positioned laterally in mid-stance gait and subjected to vehicle impact at 40 km/h with either a small sedan (n=3) or a large SUV (n=3). Detailed descriptions of the pelvic and lower extremity injuries are presented in conjunction with global and local kinematics data and high speed video images. Injured PMHS knee joints reached peak lateral bending angles between 25 and 85 degrees (exceeding published injury criteria) at bending rates between 1.1 deg/ms and 3.7 deg/ms.

A dynamic rollover test system (DRoTS) capable of simulating rollover crashes in a laboratory was designed for research use at the University of Virginia. The goal of the current study is to describe the system's capabilities and specifications as well as to explore the limitations of the system's ability to simulate rollover crashes. The test apparatus was designed to permit simulation of a single roof-to-ground interaction of a rollover crash with the potential to be modified for evaluation of pre-roof contact occupant motion. Special considerations were made to permit testing of both dummies and post-mortem human surrogates in both production vehicles and a parametric test buck. DRoTS permits vertical translation, pitch, and roll of the test vehicle while constraining longitudinal and lateral translations and yaw. The study details the ranges of test parameters capable with the DRoTS and evaluates the limitations of the system relative to rollover crash conditions.

The accidentological studies dealing with automotive side collisions suggest that the pelvis is very vulnerable. Car manufacturers are more and more concerned with the protection of the occupant in lateral impact, but there is a lack of knowledge of the behavior of the pelvic bony structure and of its biomechanical tolerances. This knowledge however is essential in order to optimize protection devices and car structures with regard to the security of the occupants. The main goal of this study is thus two-fold: First, a field accident analysis was carried out in order to document the lesions and the injury mechanisms encountered in lateral impact. The accident database of the Laboratory of Accidentology and Biomechanics (LAB) was used and a sample of 219 injured occupants sustaining 381 injuries in lateral collision enables to evaluate the most frequent injuries and their location. Those injuries were also analyzed with regard to the car characteristics.

The Frangible Abdomen is a crushable Styrofoam insert for the abdominal region of the Hybrid III family of dummies, which has biofidelity, and assesses the occurrence of submarining and its risk of injury. It was first developed for the mid-sized male Hybrid III dummy. This paper describes the design of the Frangible Abdomen for the small female Hybrid III dummy, and how to use it to assess the occurrence and the risk of injury from submarining. The force-deflection properties of the mid-sized male insert were scaled to the small female dimension using equal stress/equal velocity scaling. Sled tests were run to compare the kinematic and dynamic performance of the baseline small female Hybrid III dummy with the same dummy modified to incorporate the Frangible Abdomen. The kinematic and submarining performance of the small female Hybrid III dummy was unchanged by the addition of the Frangible Abdomen. The Frangible Abdomen was easy to install and use, and had excellent repeatability.

This study applies a detailed finite element model of the human body to simulate occupant knee impacts experienced in vehicular frontal crashes. The human body model includes detailed anatomical features of the head, neck, chest, thoracic and lumbar spine, abdomen, and lower and upper extremities. The material properties used in the model for each anatomic part of the human body were obtained from test data reported in the literature. The total human body model used in the current study has been previously validated in frontal and side impacts. Several cadaver knee impact tests representing occupants in a frontal impact condition were simulated using the previously validated human body model. Model impact responses in terms of force-time and acceleration-time histories were compared with test results. In addition, stress distributions of the patella, femur, and pelvis were reported for the simulated test conditions.

This paper presents the results of biomechanical testing of the SID-IIs beta+-prototype dummy by the Occupant Safety Research Partnership. The purpose of this testing was to evaluate the dummy against its previously established biomechanical response corridors for its critical body regions. The response corridors were scaled from the 50th percentile adult male corridors defined in International Standards Organization Technical Report 9790 to corridors for a 5th percentile adult female, using established International Standards Organization procedures. Tests were performed for the head, neck, shoulder, thorax, abdomen and pelvis regions of the dummy. Testing included drop tests, pendulum impacts and sled tests. The biofidelity of the SID-IIs beta+-prototype was calculated using a weighted biomechanical test response procedure developed by the International Standards Organization.

Airbag deployments are associated with loud noise of short duration, called impulse noise. Research performed in the late 1960's and early 1970's established several criteria for assessment of the risk of impulse noise-induced hearing loss for military weapons and general exposures. These criteria were modified for airbag noise in the early 1970's, but field accident statistics and experimental results with human volunteers exposed to airbags do not seem to agree with the criteria. More recent research on impulse noise from weapons firing, in particular that of Price & Kalb of the US Army Research Laboratory, has led to development of a mathematical model of the ear. This model incorporates transfer functions which alter the incident sound pressure through various parts of the ear. It also calculates a function, called the “hazard”, that is a measure of mechanical fatigue of the hair cells in the inner ear.

Two-dimensional film analysis was conducted to study the kinematics of the head and neck of 17 restrained human volunteers in 24 frontal impacts for acceleration levels from 6g to 15g. The trajectory of the head center of gravity relative to upper torso reference points and the rotation of head and neck relative to the lower torso during the forward motion phase were of particular interest. The purpose of the study was to analyze the head-neck kinematics in the mid-sagittal plane for a variety of human volunteer frontal sled tests from different laboratories using a common analysis method for all tests, and to define a common response corridor for the trajectory of the head center-of-gravity from those tests.

The present study describes the development of a refined finite element model of the human pelvis. The objectives of this research work were to: Statistically study the human pelvis geometry, and develop a parameterized model. Mechanically validate the model with regard to the available in-house experimental data. Model the injury mechanisms observed in the experimental studies. The significant dimensions of the pelvis were identified by statistical analysis of the pelvis geometry based on the Reynolds et al. data [1]. Those dimensions were used to classify the in-house tested pelves. An interpolation technique (Kriging [2, 3, 4, 5, 6, 7 and 8]) was then used in order to distort a reference mesh and adapt its geometry to the measured geometry of the tested pelvis. The mechanical validation of the model was carried out by comparing numerical and experimental results, and the influence of the geometrical variations on the behavior of the pelvis was thus assessed.

Two post-mortem human subjects were subjected to dynamic, non-injurious (up to 20% chest deflection) anterior shoulder belt loading at 0.5 m/s and 0.9 m/s loading rates. The human surrogates were mounted to a stationary apparatus that supported the spine and shoulder in a configuration comparable to that achieved in a 48 km/h sled test at the time of maximum chest deformation. A hydraulically driven shoulder belt was used to load the anterior thorax which was instrumented with a load cell for measuring reaction force and uniaxial strain gages at the 4th and 8th ribs. In addition, the deformation of the chest was measured using a 16- camera Vicon 3D motion capture system. In order to investigate the chest deformation pattern and ribcage loading in greater detail, a human finite element (FE) model of the thorax was used to simulate the tests.

This investigation explored THOR's force-deflection response to upper abdomen/lower ribcage steering wheel rim impacts in comparison to the Hybrid III and cadaver test subjects. The stationary subjects were impacted by a ballasted surrogate wheel propelled at 4 m/s, a test condition designed to approximate the upper abdomen impacting a steering wheel rim in a frontal crash. Both the standard THOR and the Hybrid III crash dummies were substantially stiffer than the cadavers. Removing THOR's torso skin and foam from the upper abdomen and replacing the standard Hybrid III abdomen with a prototype gel-filled unit produced force-deflection results that were more similar to the cadavers. THOR offers advantages over the Hybrid III because of its ability to measure abdominal deflection. THOR, with modification, would be a useful instrument with which to assess the crashworthiness of steering assemblies and restraint systems in frontal crashes.

A finite element human model has been developed to simulate occupant behavior and to estimate injuries in real-world car crashes. The model represents an average adult male of the US population in a driving posture. Physical geometry, mechanical characteristics and joint structures were replicated as precise as possible. The total number of nodes and materials is around 67,000 and 1,000 respectively. Each part of the model was not only validated against human test data in the literature but also for realistic loading conditions. Additional tests were newly conducted to reproduce realistic loading to human subjects. A data set obtained in human volunteer tests was used for validating the neck part. The head-neck kinematics and responses in low-speed rear impacts were compared between the measured and calculated results. The validity of the lower extremity part was examined by comparing the tibia force in a foot impact between the test data and simulation results.

This paper presents a technique for developing corridors from individual subject responses contained in experimental biomechanical data sets. Force-deflection response is used as an illustrative example. The technique begins with a method for averaging human subject force-deflection responses in which curve shape characteristics are maintained and discontinuities are avoided. Individual responses sharing a common characteristic shape are averaged based upon normalized deflection values. The normalized average response is then scaled to represent the given data set using the mean peak deflection value associated with the set of experimental data. Finally, a procedure for developing a corridor around the scaled normalized average response is presented using standard deviation calculations for both force and deflection.

This paper discusses struck-side occupant thoracic response to side-impact loading and the requirements of a sled system capable of reproducing the relevant motions of a laterally impacted vehicle. A simplified viscoelastic representation of a thorax is used to evaluate the effect of the door velocity-time profile on injury criteria and on the internal stress state of the thorax. Simulations using a prescribed door velocity-time profile (punch impact) are contrasted against simulations using a constant-velocity impact (Heidelberg-type impact). It is found that the stress distribution and magnitude within the thorax, in addition to the maximum thorax compression and viscous response, depend not only on the door-occupant closing velocity, but also on the shape of the door velocity-time profile throughout the time of contact with the occupant. A sled system capable of properly reproducing side-impact door and seat motion is described.

This paper presents an analysis of the displacement measurement of the Hybrid III 50th percentile male dummy chest in quasistatic and dynamic loading environments. In this dummy, the sternal chest deformation is typically characterized using a sliding chest potentiometer, originally designed to measure inward deflection in the central axis of the dummy chest. Loading environments that include other modes of deformation, such as lateral translations or rotations, can create a displacement vector that is not aligned with this sensitive axis. To demonstrate this, the dummy chest was loaded quasistatically and dynamically in a series of tests. A string potentiometer array, with the capability to monitor additional deflection modes, was used to supplement the measurement of the chest slider.

Studies show that the pedestrian population at high risk of injury consists of both young children and adults. The goal of this study is to gain understanding in the mechanisms that lead to injuries for children and adults. Multi-body pedestrian human models of two specific anthropometries, a 6year-old child and a 50th percentile adult male, are applied. A vehicle model is developed that consists of a detailed rigid finite element mesh, validated stiffness regions, stiff structures underlying the hood and a suspension model. Simulations are performed in a test matrix where anthropometry, impact speed and impact location are variables. Bumper impact occurs with the tibia of the 50th percentile adult male and with the thigh of the 6-year-old child. The head of a 50th percentile male impacts the lower windshield, while the 6-year-old child's head impacts the front part of the hood.