Investigation And Numerical Evaluation On Low-velocity Impact And Strength-after-impact Of Hollow Integrated Sandwich Composites

Composites are sensitive to the load of impact. The in-plane properties of composites, especially the composite with sandwich structure, are seriously affected by the damage caused by impact. As a new kind of 3D woven mezzanine composite, hollow integrated sandwich composite material has good property of integration and can overcome the weaknesses of hierarchical after impact and bad property of resistance of impact which the traditional mezzanine composites have. Since the property of low-velocity impact is a significant parameter in widely promotion of appliance, this article focuses on the property of low-velocity impact and residual strength after impact of the material and investigates it with a great deal of FEM calculation, and compares them with experimental results.Firstly, a minimal structure element is modeled and the in-plane modulus of the hollow integrated sandwich composite material is predicted. Based on the model and prediction, the author has modeled the dynamic finite element analysis of the material and simulated the process of impact with different energy. Then the curve of stress-time and damage situation has been obtained.The FEM model of hollow integrated sandwich composite material with impact damage has been built. The residual strength has been analyzed and predicted by means of Equivalent opening and Sub-layer buckling. And the experiments of low-velocity impact and residual strength of the material have been carried on. The comparison between theory and experiments suggests that it is reasonable to build the model. And the property of the material above has also been compared with sandwich composite in the situation of low-velocity impact...