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The number of passenger cars equipped with side air bags is steadily increasing. With the aim of investigating the mechanical responses and the injuries of the arm under the influence of a side air bag, tests in probably higher injury risk configurations with dummies and cadavers were performed. The air bag was installed at the outer side of the seat back, with the subject seated in the driver or front passenger seat of a passenger car. During the inflation of the air bag, the left or right forearm of the subject was positioned on the arm rest while the upper arm made contact with the seat back edge. The volume of the thorax air bag was 15 litres and for the thorax-head air bag 28 litres. The dummy was instrumented at the thorax c.g. shoulder, elbow and wrist with triaxial accelerometers. In the cadaver, triaxial accelerations in three orthogonal directions were measured at the upper and the lower humerus, the upper radius and the lower radius and the first thoracic vertebrae.

Experimental tests were performed on the modified Polar-II pedestrian dummy lower extremity components to evaluate their biofidelity in lateral impact loading corresponding to a 40 km/h pedestrian-car collision. The bending moment-angle response from a newly developed knee joint, dynamically loaded in four-point valgus bending, was compared against previously published postmortem human subject (PMHS) response corridors. In addition to the stiffness characteristics of the knee joint, individual ligament forces were also recorded during the bending tests. The evaluated force-relative elongation response of the medial collateral ligament (MCL) in the new knee was compared against PMHS data on MCL tensile stiffness. Lower extremity long bones developed for improved anthropometrical accuracy and deformability were dynamically loaded in latero-medial three-point bending.

This paper presents a study characterizing the interaction between a small female upper extremity and a deploying side air bag. The results are based on 12 tests with small female cadavers, and 15 tests with the instrumented SAE 5th percentile female upper extremity attached to the 5th percentile Hybrid III female dummy. The upper extremity was loaded by a deploying seat mounted thoracic side air bag in a static test environment. Three types of inflators were used that varied in peak pressure and pressure onset rate. Three upper extremity positions where chosen that maximized loading to the humerus and elbow joint. Upper extremity instrumentation for both the cadaver and dummy tests included accelerometers and angular rate sensors on the forearm, humerus, and upper spine. Additional instrumentation on the cadavers included strain gage rosettes on the anterior and posterior humerus.

A biaxial test procedure is used to assess the constitutive properties of polymers in tension. The constitutive constants are derived for high strain rate applications such as those associated with crashworthiness studies. The test procedure is used in conjunction with a time- and strain-dependent quasi-linear viscoelastic constitutive law consisting of a Mooney-Rivlin formulation combined with Maxwell elements. The procedure is demonstrated by describing the stress vs. strain relationship of a rubber specimen subjected to a step-relaxation input. The constitutive equation is transformed from a nonlinear convolution integral to a set of first order differential equations. These equations, with the appropriate boundary conditions, are solved numerically to obtain transient stresses in two principal directions. Material constants for use in the explicit LS-Dyna non-linear finite element code are provided.

Pediatric pedestrians are frequently involved in Pedestrian versus Motor Vehicle Collisions (PMVCs). While in recent years, the automotive industry has worked towards making cars less aggressive to pedestrians, the efforts have mainly focused on adult pedestrian safety. When they have included considerations for children, only head injuries have been evaluated. The development of automotive counter-measures that provide protection for both adult and pediatric pedestrians requires access to injury criteria for the entire body that specifically account for both the age-dependent tissue properties and the pedestrian's size. The objective of the present study is to derive lateral injury criteria for the head, neck, thorax, abdomen and pelvis that can be used in finite element and multi-body simulations of PMVCs involving the 6-year-old pedestrian (corresponding injury criteria for the upper and lower extremities are derived in part II of this study).

This paper presents a parametric study that utilized the CVS/ATB multi-body simulation program to investigate the interaction of the hand and wrist with a door handgrip during side air bag loading. The goal was to quantify the relative severity of various hand and handgrip positions as a guide in the selection of a test matrix for laboratory testing. The air bag was represented as a multi-body system of ellipsoidal surfaces that were created to simulate a prototype seat-mounted thorax side air bag. All simulations were set in a similar static test environment as used in corresponding dummy and cadaver side air bag testing. The occupant mass and geometric properties were based on a 5th percentile female occupant in order to represent a high-risk segment of the adult population. The upper extremity model consisted of wrist and forearm rotations that were based on human volunteer data.

Pediatric pedestrians are frequently involved in Pedestrian versus Motor Vehicle Collisions (PMVCs). While in recent years, the automotive industry has worked towards making cars less aggressive to pedestrians, the efforts have mainly focused on adult pedestrian safety. When they have included considerations for children, only head injuries have been evaluated. The development of automotive countermeasures that provide protection for both adult and pediatric pedestrians requires access to injury criteria for the entire body that specifically account for both the age-dependent tissue properties and the pedestrian's size. The objective of the present study is to derive lateral injury criteria for the upper and lower extremities that can be used in finite element and multi-body simulations of PMVCs involving the 6-year-old pedestrian (corresponding injury criteria for the head, neck, thorax, abdomen and pelvis are derived in part I of this study).

Computer simulations, dummy experiments with a new enhanced upper extremity, and small female cadaver experiments were used to analyze the small female upper extremity response under side air bag loading. After establishing the initial position, three tests were performed with the 5th percentile female hybrid III dummy, and six experiments with small female cadaver subjects. A new 5th percentile female enhanced upper extremity was developed for the dummy experiments that included a two-axis wrist load cell in addition to the existing six-axis load cells in both the forearm and humerus. Forearm pronation was also included in the new dummy upper extremity to increase the biofidelity of the interaction with the handgrip. Instrumentation for both the cadaver and dummy tests included accelerometers and magnetohydrodynamic angular rate sensors on the forearm, humerus, upper and lower spine.

Axial loading of the foot/ankle complex is an important injury mechanism in vehicular trauma that is responsible for severe injuries such as calcaneal and tibia pilon fractures. Axial loading may be applied to the leg externally, by the toepan and/or pedals, as well as internally, by active muscle tension applied through the Achilles tendon during pre-impact bracing. In order to evaluate the effect of active muscle tension on the injury tolerance of the foot/ankle complex, blunt axial impact tests were performed on 44 isolated lower legs with and without experimentally simulated Achilles tension. The primary fracture mode was calcaneal fracture in both groups, but tibia pilon fractures occurred more frequently with the addition of Achilles tension. Acoustic emission demonstrated that fracture initiated at the time of peak local axial force.

The prevention of lower extremity injuries to front seat car occupants is a priority because of their potential to cause long-term impairment and disability. To determine the types and mechanisms of lower extremity injuries in frontal collisions, studies under controlled test conditions are needed. Sled tests using belt-restrained cadavers and dummies were conducted, in which footwell intrusion was simulated via a plane surface or simulated brake pedal. Human cadavers in the age range from 30 to 62 years and Hybrid III dummies were used. The footwell intrusion had both translational (135 mm) and rotational (30 degrees) components. Maximum footwell intrusion forces and accelerations were measured. The lower legs were instrumented with accelerometers and a ""six axis'' force-moment transducer was mounted in the mid shaft of the left tibia.

Real-world crash investigations have suggested that lower limb injury risk is increased with the occurrence of toepan intrusion in a frontal collision. In order to more closely evaluate the effects of different modes of toepan intrusion, a rotational and translational intrusion device was built for the test sled at the University of Virginia. Sled tests were performed at a velocity of 56 km/h with a belted Hybrid III occupant and a simulated knee bolster and steering wheel air bag. Lower limb injury risk measures were obtained with Hybrid III and Thor Lx dummy lower extremities. Dummy response variables of interest included tibia axial and shear loads, tibia bending moments, ankle rotations and foot and tibia accelerations. The tests were conducted with no intrusion and with a translational intrusion with a peak deceleration of approximately 175 g's with 14 cm of translation.

Multiple series of frontal sled tests were performed to evaluate the new Thor-Lx/HIIIr lower extremity developed by the National Highway Traffic Safety Administration for retrofit use on the 50th percentile male Hybrid III. This study's objective was to compare the Thor-Lx/HIIIr to the existing Hybrid III dummy leg (HIII) from the standpoint of repeatability and effects on femur and upper body response values.\ The test-to-test repeatability of the dummy responses, as measured by the coefficient of variation (CV), was generally acceptable (CV < 10%) for all of the test conditions for both legs. Overall, tests with the Thor-Lx/HIIIr legs produced upper body movement and injury criteria values for the head and chest that were acceptably consistent and were generally indistinguishable from those produced with the HIII leg. Low right femur loads, which ranged from 4 to 25 percent of the injury assessment reference value, varied substantially test-to-test for tests with both types of legs.

This paper presents a load distribution-specific viscoelastic structural characterization of the Hybrid III 50th percentile male anthropomorphic test dummy thorax. The dummy is positioned supine on a high-speed material testing machine and ramp-and-hold tests are performed using a distributed load, a hub load, and a diagonal belt load applied to the anterior thorax of the dummy. The force-deflection response is shown to be linear viscoelastic for all loading conditions when the internal dummy instrumentation is used to measure chest deflection. When an externally measured displacement (i.e., a measurement that includes the superficial skin material) is used for the characterization, a quasilinear viscoelastic characterization is necessary. Linear and quasilinear viscoelastic model coefficients are presented for all three loading conditions.

Crash test dummies rely on biomechanical data from cadaver studies to biofidelically reproduce loading and predict injury. Unfortunately, it is difficult to obtain equivalent measurements of leg loading in a dummy and a cadaver, particularly for bending moments. A methodology is presented here to implant load cells in the tibia and fibula while minimally altering the functional anatomy of the two bones. The location and orientation of the load cells can be measured in all six degrees of freedom from post-test radiographs. Equations are given to transform tibial and fibular load cell measurements from a cadaver or dummy to a common leg coordinate frame so that test data can be meaningfully compared.

Previous lateral knee bending and shear tests have reported knee joint failure moments close to failure bending moments for the tibia and femur. Eight tibias, eight femurs and three knee joints were tested in lateral bending and two knee joints were tested in lateral shear. Seven previous studies on femur bending, five previous studies on tibia bending, two previous studies on knee joint bending, and one on shear were reviewed and compared with the current tests. All knee joint failures in the current study were either epiphysis fractures of the femur or soft tissue failures. The current study reports an average lateral failure bending moment for the knee joint (134 Nm SD 7) that is dramatically lower than that reported in the literature (284-351 Nm), that reported in the current study for the tibia (291 Nm SD 69) and for femur (382 Nm SD 103).

A current priority in Europe and the USA is the development of improved side collision dummies. This report presents the results of sled tests with three test subject types: cadavers (PMHS), EUROSID 1 and BIOSID. Twenty one (21) cadaver tests were performed and 9 dummy tests a piece. The left side of the test subjects were impacted under one of two different test conditions: 24 km/h rigid wall and 32 km/h padded wall. The cadavers were instrumented with a 12 thoracic, and triaxial pelvic accelerometer arrays. Thoracic deformation was calculated from rib accelerations. The dummies were instrumented in their standard formats, which included the ability to measure coronal plane thoracic deformation. For all test subject types and measurement locations the 3ms. acceleration standard deviations were low. Mean 3ms. accelerations showed no consistent relationship in magnitude between subject types. The measured dummy rib deformations were compared to the calculated cadaver deformations.

The objectives of this study were to evaluate and compare the responses, repeatability, and durability of the Thor-Lx/HIIIr and Hybrid III/Denton lower extremities in frontal sled tests. Effectiveness of the two limb types was studied by evaluating responses in different test configurations using existing and proposed Injury Assessment Reference Values (IARVs) for both leg designs. Hybrid III or Thor-Lx legs were attached to the distal femurs of a 50th percentile male Hybrid III dummy, which was subjected to three series of 56 km/h frontal sled tests with and without toepan intrusion. Due to the design differences, many of the absolute response values were different between the Hybrid III and Thor-Lx legs. The expanded measurement capabilities, modified geometry and refined responses of the Thor-Lx limbs provide a more thorough and conservative judgment of injury risk.

This paper compares restrained Hybrid III and THOR thoracic kinematics and cadaver injury outcome in 30° oblique frontal and in full frontal sled tests. Peak shoulder belt tension, the primary source of chest loading, changed by less than four percent and peak chest resultant acceleration changed by less than 10% over the 30° range tested. Thoracic kinematics were likewise insensitive to the direction of the collision vector, though they were markedly different between the two dummies. Mid-sternal Hybrid III chest deflection, measured by the standard sternal potentiometer and by supplemental internal string potentiometers, was slightly lower (∼10%) in the oblique tests, but the oblique tests produced a negligible increase in lateral movement of the sternum. In an attempt to understand the biofidelity of these dummy responses, a series of 30-km/h human cadaver tests having several collision vectors (0°, 15°, 30°, 45°) was analyzed.

The University of Virginia is investigating the biomechanical response and the injury tolerance of the lower extremities. This paper presents the experimental and simulation work used to study the injury patterns and mechanisms of the ankle/foot complex. The simulation effort has developed a segmented lower limb and foot model for an occupant simulator program to study the interactions of the foot with intruding toepan and pedal components. The experimental procedures include static tests, pendulum impacts, and full-scale sled tests with the Advanced Anthropomorphic Test Device and human cadavers. In these tests, the response of the lower extremities is characterized with analogous dummy and cadaver instrumentation packages that include strain gauges, electrogoniometers, angular rate sensors, accelerometers, and load cells. An external apparatus is applied to the surrogate's lower extremities to simulate the effects of muscle tensing.

The response and risk of injury for occupants in frontal crashes are more severe when structural deformation occurs in the vehicle interior. To reproduce this impact environment in the laboratory, a sled system capable of producing structural intrusion in the footwell region has been developed. The system couples the hydraulic decelerator of the sled to actuator pistons attached to the toepan and floorpan structure of the buck. Characterization of the footwell intrusion event is based on developing a toepan pulse analogous to the acceleration pulse used to characterize sled and vehicle decelerations. Preliminary sled tests with the system indicate that it is capable of simulating a complex sequence of toepan/floorpan translations and rotations.