A Study of the Vehicle Structure Crashworthiness in Dolly and Curb-Trip Rollover Tests

Rollover crashes can be the most dangerous vehicular crashes among all crash types which have a higher fatality rate than other kinds of crashes. The orthogonal design was adopted to evaluate structure parameters how to affect the vehicle rollover crashworthiness in dolly and curb-trip tests. It is simulated with a finite element model of SUV, which has been developed previously. The parameters are based on maximum vertical roof deforming velocity, maximum vertical deformation and lateral roof deformation which nearby occupant head. They have been selected as dependent variables or responses which reflect roof stiffness and roof crush magnitude respectively. There are 11 structure factors which have an effect on the vehicle rollover crashworthiness. It can be determined under the location of crash zone in rollover. Those factors have significant effects to the vertical roof deformation, lateral roof deformation and vertical roof deforming velocity. The result can be obtained from a series of the analysis. The main effects are compared with those factors to vertical and lateral roof deformation in dolly and curb-trip tests.

Study on the Influence of Deforming Velocity on Steel Ball Quality Based on DEFORM

The ball defects generated in skew rolling process have restricted to large extent the further application of skew rolling technology in ball manufacturing industry. Research was carried out so as to find the factors and laws of influencing on skew rolling ball quality. It was found by analyzing the forces exerting on the ball that the deforming velocity of ball had the largest influence on the resistance to deformation. Simulations were done respectively under different roller obliquities, different distances between two guide plates, and different rotation speeds of rollers by means of DEFORM-3D software. Finally, the influencing factors and laws on ball quality were discovered.

CORRECTION OF LATERAL INERTIA EFFECT IN SHPB

A theoretical analysis of the stress state in specimen of the SHPB experiment was performed in consideration of lateral inertia effect. The nonuniformity of lateral stress in specimen and variety of deforming velocity in the loading process were taken into account in the analysis. A formula to correcting the lateral inertia effect was obtained. The force and deformation velocity of specimen-bar interfaces during the loading process got from a numerical simulation of SHPB were used to verify the theoretical analysis formula. It shows that the deviation of reconstructed curve from the inputted relationship can be brought down with the correction formula.