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The objective of the current study was to provide a comprehensive characterization of human biomechanical response to whole-body, lateral impact. Three approximately 50th-percentile adult male PMHS were subjected to right-side pure lateral impacts at 4.3 ± 0.1 m/s using a rigid wall mounted to a rail-mounted sled. Each subject was positioned on a rigid seat and held stationary by a system of tethers until immediately prior to being impacted by the moving wall with 100 mm pelvic offset. Displacement data were obtained using an optoelectronic stereophotogrammetric system that was used to track the 3D motions of the impacting wall sled; seat sled, and reflective targets secured to the head, spine, extremities, ribcage, and shoulder complex of each subject. Kinematic data were also recorded using 3-axis accelerometer cubes secured to the head, pelvis, and spine at the levels of T1, T6, T11, and L3. Chest deformation in the transverse plane was recorded using a single chestband.

A total of eight low-speed, rear-end impact tests using two Post Mortem Human Subjects (PMHS) in a seated posture are reported. These tests were conducted using a HYGE-style mini-sled. Two test conditions were employed: 8 kph without a headrestraint or 16 kph with a headrestraint. Upper-body kinematics were captured for each test using a combination of transducers and high-speed video. A 3-2-2-2-accelerometer package was used to measure the generalized 3D kinematics of both the head and pelvis. An angular rate sensor and two single-axis linear accelerometers were used to measure angular speed, angular acceleration, and linear acceleration of T1 in the sagittal plane. Two high-speed video cameras were used to track targets rigidly attached to the head, T1, and pelvis. The cervical spine kinematics were captured with a high-speed, biplane x-ray system by tracking radiopaque markers implanted into each cervical vertebra.

Component tests were conducted in order to evaluate the biofidelity of the THOR-NT on the head, neck, thorax, abdomen, face, femur, and lower extremity (THOR-Lx). The biofidelity of the dummy was evaluated by comparing its biofidelic responses with the PMHS response corridors. Likewise, component tests on each body part of the Hybrid III were conducted, and the biofidelity between THOR-NT (THOR-Lx) and Hybrid III were compared. The THOR tests were subject to test procedures established by GESAC, Inc./NHTSA; the THOR-Lx tests were subject to NHTSA/VRTC procedures. Responses on the head and femur of both the THOR-NT and Hybrid III were within the PMHS response corridors. However, for other body parts - although each component of THOR-NT did not yield results that satisfied all the PMHS response corridors - the responses of THOR-NT were closer to the corridors than those of the Hybrid III.

The structural differences between the Thor-NT and Thor-FT dummies, which have been proposed as next-generation dummies for frontal crash tests, were examined and the differences in dynamic response were verified by testing. Tests were performed on a HYGE sled simulating a frontal crash at an impact speed of 56 km/h. The 3-point seatbelt plus air bag combination was adopted as the restraint mechanism. Differences in characteristics of the two dummies in the neck, thorax, and abdomen were found by calibration tests. Test results showed that the variation in shape of the abdominal area of the pelvis generates some disparity in the flexion of the thorax and abdomen.

Numerous studies of pelvic tolerance to lateral impact aimed at protecting car occupants have been conducted on Post Mortem Human Subjects (PMHSs) in a sitting posture. However, it remains unclear whether or not the results of these studies are relevant when evaluating the injury risk to walking pedestrians impacted by a car. Therefore, the first objective of the present study is to determine the injury tolerance and to describe the injury mechanisms of the human pelvis in lateral impacts simulating car-pedestrian accidents. The second objective is to obtain data for validation of mathematical models of the pelvis. In-vitro experiments were conducted on twelve PMHSs in simulated standing position. The trochanter of each PMHS was hit by a ram at speed of 32 km/h, and the pelvic motion was constrained by a bolt. This type of pelvic constraint is difficult to simulate in mathematical models.

Regarding THOR-50AM dummy lower extremities (hereafter referred to as ""THOR''and ""THOR-LX'') developed as an assembly of lower extremities for next-generation dummies in frontal impact test, we have conducted a series of tests as follows. HYGE sled tests with a toe-board simulating the impact upon intrusion into the vehicle compartment around the occupant feet, dummy dropping tests with two different postures; one is the upright posture with the knees set straight and another is the posture with the knees bent, in order to apply impact loads and to measure/evaluate the impact response characteristics.

In recent years, several kinds of seat systems that aim to reduce cervical spinal injuries in rear impacts, so called ‘whiplash injuries’, have been released by some car manufacturers and seat suppliers in the world. Meanwhile, several kinds of dummies have been developed to be representatives of occupants under such conditions. One of these is the BioRID II equipped with a realistic spine constructed of multiple vertebrae similar to that of a human. It is regarded as the most biofidelic dummy for low speed rear impact. Using this dummy, some typical ‘whiplash protective’ seat systems currently available were dynamically tested to see their performance on injury reduction. From the results of these tests, the design direction to lessen the injury level more efficiently was determined.

The non-physiological motions of human cervical vertebrae were analyzed in volunteer tests for rear-end impacts and were considered to be an important parameter for neck injuries. The objectives of this study are to improve the Marko de Jager neck model using volunteer test data and to analyze the influence of horizontal and vertical accelerations on cervical vertebral motion. In the beginning of this study, a neck model was positioned based on X-ray cineradiography of a volunteer. Motions of each vertebra were compared with those of volunteer test data for low speed rear-end impacts (4, 6, 8km/h). In these comparisons, the differences of vertebrae motions between the neck model and the volunteer tests were found. To improve the validity of the neck model, the connection properties and the bending properties of the upper and lower vertebrae of the model were modified to increase rigidity.

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.

It is important to more clearly identify the relationship among the ramping-up motion, straightening of the whole spine, and cervical vertebrae motion in order to clarify minor neck injury mechanism. The aim of the current study is to verify the influence of the change of the spine configuration on human cervical vertebral motion and on head/neck/torso kinematics under low speed rear-end impacts. Seven healthy human volunteers participated in the experiment under the supervision of an ethics committee. Each subject sat on a seat mounted on a sled that glided backward on rails and simulated actual car impact acceleration. Impact speeds (4, 6, and 8 km/h), and seat stiffness (rigid and soft) without headrest were selected. During the experiment, the change of the spine configuration (measured by a newly developed spine deformation sensor with 33 paired set strain gauges and placed on the skin) and the interface load-pressure distribution was recorded.

The most important tool to date for testing seat-systems in rear impacts is a crash test dummy. However, investigators have noted limitations of the most commonly used dummy, the Hybrid III. Although the BioRID I is a step closer to a biofidelic crash test dummy it is not user-friendly and the straightening of the thoracic spine kyphosis is smaller than that of humans. The objective of this study is to compare the performance of the latest prototype of the BioRID, the P3, with those of volunteers. The BioRID P3 has new neck muscle substitutes, a softer thoracic spine and a softer rubber torso than does the BioRID I. The BioRID P3 was validated against volunteer test data in both a rigid and a standard seat without head restraints. The dummy kinematic performance, pressure distribution between subject and seatback, spine curvature, neck loads and accelerations were compared to those of seven volunteers and a Hybrid III fitted with a standard neck.

The main objective of this study is to determine the damage tolerance and describe the damage mechanisms of the extended human knee when it is exposed to lateral impact loads in car-pedestrian accidents, particularly those that occur at a low velocity (20 km/h), and compare the results with those obtained at a high velocity (40 km/h). In-vitro experiments with human subjects were conducted where only the purest possible shearing deformation or the purest possible bending deformation affected the knee region at the time. Five experiments were performed in the shearing setup and another five in bending setup. The peak values of the shearing force and the bending moment related to the damage of knee ligaments and bone fractures were calculated at the knee joint level. Damages were assessed by dissecting the lower extremity. When the knee joint was exposed to the “purest possible shearing deformation”, the common initial damagemechanism was ligament damage related to ACL (60% of cases).

The compatibility problems of the mini car in car-to-car frontal collision and car-pedestrian accident are discussed using accident data and computer simulations. In our analysis of the accident data in Japan, the number of fatalities was investigated using the vehicle masses and classes. It was found that the cars with identical mass are most compatible since the injuries per accident are minimal and injury risks to the driver in both cars are the same. The analysis of the car class indicated that the mini car and the sports utility vehicle are the most incompatible car types, with low and high aggressivity, respectively. Our accident analysis in the present study shows that the safety of mini cars is the key point in achieving the compatibility in Japan. Computer simulations using MADYMO were carried out of crashes of mini car into a rigid wall and into a large car.

The main objective of this study is to determine the damage tolerance and to describe the damage mechanisms of the extended human knee when it is exposed to lateral impact loads in pedestrian accidents, particularly those that occur at high velocity. An experimental method for assessing the damage tolerance of the knee region to loads acting at the extended lower extremity was developed. In-Vitro experiments with human subjects were conducted where only the purest possible shearing deformation or the purest possible bending deformation affected the knee region at the time. Ten experiments at a velocity level of 40 km/h were performed in a shearing and a bending setup, respectively. The peak values of the shearing force and the bending moment related to the damage of knee ligaments and bone fractures were calculated at knee joint level. Damages were assessed by dissecting the lower extremity.

Twelve volunteers participated in the experiment under the supervision of Tsukuba University Ethics Committee. The subjects sat on a seat mounted on a newly developed sled that simulated actual car impact acceleration. We selected impact speeds (4, 6 and 8 km/h), seat stiffness, neck muscle tension, and alignment of the cervical spine for the parameter study of the head-neck-torso kinematics and cervical spine responses. The effects of those parameters were studies without headrest. The muscle activity was measured with surface electromyography. The cervical vertebrae motion was recorded by cineradiography (90 frames/s X-ray) and analyzed to quantify the rotation and translation of cervical vertebrae at impact. Furthermore, the motion patterns of cervical vertebrae in the crash motion and in the normal motion were compared. Subject's muscles in the relaxed state did not affect the head-neck-torso kinematics upon rear-end impact.

The shearing and bending injury mechanisms of the knee joint are recognised as two important injury mechanisms associated with car-pedestrian crash accidents. A study on shearing and bending response of the knee joint to a lateral impact loading was conducted with a 3D multibody system model of the lower extremity. The model consists of foot, leg and thigh with concentrated upper body mass. The body elements are connected by joints, including an anatomical knee joint unit that consists of the femur condyles, tibia condyles and tibia1 intercondylar eminence as well as ligaments. The biomechanical properties of the model were derived from literature data. The model was used to simulate two series of previously performed experiments with lower extremity specimens at lateral impact speeds of 15 and 20 km/h.

A new mathematical multibody-system model of the whole human body was developed to simulate the pedestrian in road accidents with cars. The aim with the model was to achieve better correlation with results from impact tests with cadaver specimens. The pedestrian model was created to be used with the Crash Victim Simulation (CVS) computer program. The model consists of fifteen segments connected by fourteen joints. The geometry and the characteristics of the body segments, and the mechanical properties of the joints are based on available anthropometrical and biomechanical data. In order to verify the pedestrian model with pervious cadaver experiments, the computer simulations were carried out in such a way that the set-up of simulations corresponded to those in the cadaver tests. The model response to following parameters was studied in the simulations: impact speed, bumper height and bumper compliance.

Improvements for pedestrian head protection in a car-pedestrian accident have been discussed in several countries. Test methods for evaluating head protection have been proposed, and most are sub-systems using rigid headforms with or without headskin. In those tests, HIC is used as a criterion for head protection. This paper discusses the test conditions and requirements of the headform impact test. The influence of different test conditions and their importance on head impact test requirements, were verified. The primary items cited are as follows: (1) The results of the rigid headform were similar to that of the human cadaver skull in cases without skull fractures. Consequently, the rigid headform can be used for the impactor simulating a condition without skull fracture. (2) In the cases of HIC≤1000, the force-deformation curves of the hoodtops showed similar characteristics with maximum dynamic deformations over 60mm. (3) Impactor mass affected the maximum acceleration and HIC.

Analysis of the results of previous simulations of pedestrian collision performed with different commercial dummies have indicated that test results do not always correspond with observations in simulations with cadavers. It seems that determining the risk of injury to pedestrians from these dummy tests may be very difficult. To study injury-related parameters in connection with mechanical dummies, 21 crash tests were performed at the Institute of Forensic Medicine at the Medical University of Hannover. Various front structures and velocities of vehicles were simulated. Two measuring tools were used for verification: a standard Hybrid II dummy, and the lower part of a Rotationally Symmetrical Pedestrian Dummy (RSPD) with no representation of the upper body. RSPD was previous developed at the Department of Injury Prevention at Chalmers University in Göteborg.

A 3D pedestrian knee joint model was developed as a first step in a new description of the whole pedestrian body for computer simulations. The model was made to achieve better correlation with the results from previous tests with biological material. The model of the knee joint includes the articular surfaces, ligaments and capsule represented by the ellipsoid and plane elements as well as the spring-damping elements, respectively. The mechanical properties of the knee joint were based on available biomechanical data. To verify the new developed model with results from tests with biological material previously performed at the Department of Injury Prevention, Chalmers University of Technology, the computer simulations were carried out with the model of the knee joint using the MADYMO 3D program.