Offset Frontal Collision Research Articles

Crushing Strength of Aluminum Honeycomb with Thinning Cell Wall

To evaluate the crash safety of automobiles, various collision tests are performed by the auto industry. In the offset frontal collision test and the side collision test, the target is an aluminum honeycomb material which has thinning cell walls. In this study, based on the analyses of the shock absorption mechanism, a new crushing strength formula is proposed. First, load-displacement curves obtained from compression tests in quasi-static condition showed an almost linear relation between a thinning rate of cell walls and a crushing strength. Second, based on Wierzbicki's theory, a new formula was proposed, which can estimate a crushing strength of a honeycomb material with thinning wall. In addition, a correcting equation which considered an elastic deformation was also proposed. Third, parametric analyses were carried out with a FE model which can simulate a delamination between cell walls. The results obtained from the theory and FEM almost corresponded to each other for a wide range of the thinning rate. Fourth, impact tests were carried out, in which the weight was dropped freely at the speed used for the automobile tests. Those results almost agreed well with the sum of the theoretical crush strength and the inside air pressure.

Application of aluminium honeycomb model using shell elements to offset deformable barrier model

This paper describes the new finite element modelling method of aluminium honeycomb using shell elements. It is our new modelling method in which the cell size of the honeycomb structure is enlarged to increase minimum mesh size, and compressive strength is controlled by thickness of shell elements. New modelling was applied to an offset deformable barrier (ODB) model and a full vehicle crash analysis was performed. The result of offset frontal collision analysis with a new honeycomb model showed better correlation with the test result than the result of previous simulations.

New Crushing Strength Formula of Aluminum Honeycomb with Thinning Cell Wall

An aluminum honeycomb which has etched cell wall is used as a shock absorbent material for the offset frontal collision test and the side collision test of automobile. In this study, based on the analyses of the shock absorption mechanism, a new crushing strength formula is proposed. Firstly, load-displacement curves obtained from compression tests in quasi-static condition showed almost linear relation between a thinning rate of cell walls R and a crushing strength. Secondly, based on Wierzbicki's theory, a new formula was proposed, which can estimate a crushing strength of honeycomb material with thinning wall. Thirdly, parametric analyses were carried out with FEM model which can simulate a delamination between cell walls. The results which were obtained from theory and FEM almost corresponded to each other for a wide range of core ratio. The proposed formula works well for R <70%. Impact tests were carried out, in which the weight was dropped freely at the speed used for automobile tests. Those results almost agreed well with the sum of the theoretical crush strength and the inside air pressure.

Incremental harmonic balance method for analysis of standard/smart vehicles-to-rigid barrier frontal collision

The aim of this paper is to investigate and to enhance crashworthiness of frontal barrier impact using a new idea of crash improvement. Two different types of smart front-end structure are proposed to support the function of the existing vehicle. The work described includes developing and analysing mathematical models of vehicle-to-rigid barrier full and offset frontal collision events for the two types of smart front-end structure. In these models, vehicle components are modelled by lumped masses and nonlinear springs. Moreover, the hydraulic cylinders are represented by non-linear damper elements. In this paper, the dynamic responses of the crash events are obtained with the aid of analytical approach using the Incremental Harmonic Balance Method (IHBM). In addition, the intrusion injury and occupant deceleration are used for interpreting the results. It is demonstrated from simulation results that significant improvements to both intrusion and deceleration injuries are obtained using the smart front-end structures.

Crash analysis and modeling of two vehicles in frontal collisions using two types of smart front-end structures: an analytical approach using IHBM

The aim of this paper is to investigate and to enhance crashworthiness of vehicle-to-vehicle full and offset frontal collisions using two smart front-end structures. Two different types of smart front-end structures, fixed and extendable, have been proposed to support the function of the existing vehicle. The work carried out in this paper includes developing and analyzing mathematical models of vehicle-to-vehicle in full and offset frontal collision events for the two types of smart front-end structures. In this paper, the dynamic responses of the crash events are obtained with the aid of an analytical approach using Incremental Harmonic Balance Method (IHBM). Moreover, the intrusion injury and occupant deceleration are used for interpreting the results. It is demonstrated from simulation results that significant improvements to both intrusion and deceleration injuries are obtained using the smart front-end structures. Furthermore, it is shown that the mathematical models are convenient and can be used in an effective way to give a quick insight of crash accidents.

Investigation of an alleged mechanism of finger injury in an automobile crash

This investigation centers on the case of an adult male whose finger was allegedly amputated by the steering wheel of his car during a crash. The subject claimed to have been driving with his left index finger inserted through a hole in the spoke of his steering wheel and was subsequently involved in an offset frontal collision with a tree. The finger was found to be cleanly severed at the mid-shaft of the proximal phalanx after the crash. This injury was alleged to have been caused by inertial loading from the rotation of the steering wheel during the crash. To determine whether this injury mechanism was plausible, three laboratory tests representing distinct loading scenarios were carried out with postmortem human surrogates loaded dynamically by the subject's steering wheel. It was found that the inertial loads generated in this loading scenario are insufficient to amputate the finger. Additionally, artificially constraining the finger to force an amputation to occur revealed that a separation at the proximal interphalangeal joint occurs rather than a bony fracture of the proximal phalanx. Based on these biomechanical tests, it can be concluded that the subject's injury did not occur during the automobile crash in question. Furthermore, it can be shown that the injury was self-inflicted to fraudulently claim on an insurance policy.

Comparison of shoulder range-of-motion and stiffness between volunteers, Hybrid III and THOR Alpha in static frontal impact loading

The aim of this study was to compare the shoulder range-of-motion and stiffness between volunteers and 50th percentile dummies in static loading conditions simulating frontal collisions. Five volunteers a Hybrid III and a THOR Alpha were positioned in a test rig where both arms were statically loaded in the forward-upward direction at 90°, 135° and 170° angles while the sternum was supported. The distances between right shoulders and sternums were estimated by means of photo analysis. The photo analysis showed that the volunteers’ range-of-motion was at least three times larger for the maximum load (200 N/arm) than those of the Hybrid III and the THOR Alpha. The results indicate that the biofidelity of the dummies used today in full-frontal, oblique and offset frontal collisions may be improved by redesigned shoulder complexes. The dummies would then better predict the human kinematics and the loading of the chest by various restraint systems.

An analysis of interior deformations in offset frontal collisions - experimental consideration of impact situation relating to lower extremity injuries of front seat occupants Minoru Sakurai (Japan Automobile Research Institute)

An analysis of interior deformations in offset frontal collisions - experimental consideration of impact situation relating to lower extremity injuries of front seat occupants Minoru Sakurai (Japan Automobile Research Institute)

Impact force vector in offset frontal collision - car to car offset deformable barrier (ODB) tets Hirotoshi Ishikawa (Japan Automobile Research Institute), Kennerly H. Digges, Jason B. Ennis (The George Washington University)

Impact force vector in offset frontal collision - car to car offset deformable barrier (ODB) tets Hirotoshi Ishikawa (Japan Automobile Research Institute), Kennerly H. Digges, Jason B. Ennis (The George Washington University)

9540075 Restitution coefficients and delta-V in offset frontal collisions Hirotoshi Ishikawa (Japan Automobile Research Institute), Kennerly H. Digges, Jason B. Ennis (The George Washington University)

9540075 Restitution coefficients and delta-V in offset frontal collisions Hirotoshi Ishikawa (Japan Automobile Research Institute), Kennerly H. Digges, Jason B. Ennis (The George Washington University)

Trauma Triage

Field triage of injured patients has the objective of rapid identification of that 5-10% with injuries serious enough to pose a risk to life. The process requires not only the identification of patients with abnormal physiology, but also those whose physiology is normal despite the fact that significant anatomic injury may exist. This paper defines relationships by which vehicle damage information available at the accident may augment the physiologic measures used for triage decisions. Vehicle velocity changes of 20 m.p.h. or more in direct frontal collisions, 22 m.p.h. or more in offset frontal collisions, and 15 m.p.h. or more in side impacts captured 90% of the patients with Injury Severity Scores of 16 or greater. The amount of vehicle damage observed with these velocity changes was found to be 20 inches of crush in direct frontal collisions, 28 inches of crush in offset frontal collisions, and 15 inches of damage in side impacts. Incorporating these findings into triage of trauma patients who exhibit normal vital signs at the accident scene may provide a more structured basis for field triage.