A rigid plastic finite element model has been developed to investigate the plastically flattening process of surface asperity in metal forming. Contact ratio between a flat rigid tool and a rough soft workpiece in the presence of bulk deformation is analyzed in detail. As a bulk strain is applied, the plastic area spreads all over the bulk except for the rigid area under the valley. Contact ratio increases with the bulk strain and normal pressure. The validity of the present model is proven by good agreement with the experimental results.

Considering nonlinear characteristics of springiness and damping element, the quarter-car suspension nonlinear dynamic model is established with ADAMS. The simulation model of suspension established, and the simulation curve of nonlinear suspension is gotten by using the numerical simulation methods. The target parameters of the piecewise linear three stage control mode of the shock absorber are studied under the different random road excitation, it would provide the theoretical basic for the nonlinear damping matching of the vehicle suspension system.

In this paper, a 3D slab method model has been developed. Two differential equations governing the longitudinal and transverse force equilibriums coupled with the Von Mises yield criterion have been solved to obtain the rolling pressure distribution. The strip speed is calculated according to the volume constancy. The Coulomb friction law with different frictional coefficient and speeds were applied to the longitudinal and transverse direction. Coupled with the roll stack deformation model and thermal model, the developed 3D slab method model was used to predict the strip profile and edge drop. The effects of bending force, reduction and transverse friction on the strip profile and edge drop have been discussed in this paper. The calculated result predicted by the 3D slab method is in very good agreement with measured results. The results have shown that the large bending force, small reduction and small friction will improve the strip profile and reduce the edge drop.

Crash simulation systems in laboratory are widely used in the development of components or protect against the crash pulse. Based on a rod control hydraulic engery absorber, the paper describes a new crash simulator providing repeatable simulation of the important parameters of the automobile deceleration pulses during crash condition. The mathematic models of absorber and the control rod design method were presented also .According to replaced the different variable diameter control rod of absorber, the simulator is simple and easy to simulate different crash pulses including total velocity and acceleration during the pulse. and the control effect of the simulator was tested and verified by experiments.

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