The Coupling Impulsive Response Of Front Face And Back Face Of Sandwich Structure

With a high energy absorption capacity, cellular material has been widely applied in protection area. However, because of its relatively low strength, it is seldom used independently but more frequently put among faces of high strength materials as core to form a sandwich structure for enhancement. Although much research has been conducted to study sandwich structure, most of them concentrate on the overall deformation of structure while the coupling impulsive response between front and back face has seldom been considered. But research shows that the stress and motion of front and back face is not always consistent. In this thesis the coupling impulsive response between front and back face is explored basing on macroscopic mechanics model and microscopic mechanics model of2D cellular materials (honeycomb) and3D cellular materials (foam). The results can provide theory basis to improve the dynamic response analysis model of sandwich structure. The main work of the thesis is described below:(1) A macroscopic simplified model of sandwich structure is built where the stress-strain curve and failure mechanism is applied. In the results, the relationship between the the corresponding impulsive force between front and back face and impact velocity is revealed qualitatively, which proves the necessity of considering coupling effects in sandwich structure model.(2) The dynamic responses of2D honeycomb sandwich structure under various impact velocities are investigated. By introducing an inertial factor, a theoretical formula is proposed for the relationship between the responsive stress between front and back face and impact velocity.(3) For two kinds of tetradecahedron model for3D foam materials, their deformation modes and dynamic plateau stresses are compared. The results shows that complete filling model has a better energy absorption capacity. Based on it, the complete filling model is selected to build a tetradecahedron model with aspect ratio of2, which is used for further analysis of deformation modes and the relationship between the plateau stress between front and back face. The results fit well with the theoretical formula previously proposed.