Structural Analysis and Design for Energy Absorption in Impact.

摘要

A general assessment of the nature of the dynamic problem of analyzing the collision of a vehicle is first given. A vehicle commonly comprises an open structure of beams and thin shells of ductile metal and the kinetic energy to be absorbed as energy of deformation is usually sufficient to cause plastic flow. This is generally localized on hinges and is associated with appreciable elastic deformation. Thus elastic-plastic theory is needed including geometrical and material non-linearities. Integration through the history of the motion is needed for solution. Theorems are given which provide approximations to the maximum plastic deformation and the duration of plastic flow without determining the whole solution. Application of these to simple models is presented. The theorems are also applied to determine the stiffness of a structural element so that it will transmit impulse to the rest of the structure without itself deforming appreciably, a so-called stiff interface. The ability of porous metal to absorb energy of deformation is also analyzed by solving the microscopic problem of collapse of the cavities. The overall macroscopic deformation laws can then be determined. Tests of the behavior of porous metal in impact are presented and related to quasistatic measurements of its deformation properties. Conclusions from these studies and recommendations for new work are given.