The Investigation And Numerical Simulation On Dynamic Plastic Buckling Of Copper Alloy Cylindrical Shells Under Axial Impact Loading

Since the particular configuration of the thin-walled metal cylindrical shells, they are applied as light infrastructure components in the area of civil engineering, chemical, mechanical, aerospace, nuclear engineering, and many other civilian and defense industrial areas. Over the years, buckling behavior of thin-walled metal cylindrical shells of different materials, under different types of impact load interests many scholars, having become an active part of the solid mechanics research;Structure Characteristics of cylindrical shells with static instability and dynamic instability, under axial impact load, are quite different, because of the interaction between stress wave effect induced by axial impact load and inertial effect caused by structure themselves. N.Jones and co-workers put forward the conception of dynamic progressive buckling and dynamic plastic buckling, through the experimental study of cylindrical shells under axial impact. Generally speaking, dynamic progressive buckling of the thin-walled metal cylindrical shells occur under the low impact velocity (vo<5m/s), while dynamic plastic buckling and dynamic progressive buckling both emerge under high impact velocity. And, Impact velocity will influence the buckling morphology, besides the effect of material properties and geometry size. However it is still obscure to determine the conditions under which dynamic progressive buckling or plastic dynamic buckling intended to turn up. Consequently, further study of the dynamic plastic buckling thin-walled metal cylindrical shells under axial impact load is particularly important.Dynamic buckling of copper alloy cylindrical shells, insensitive to the strain rate, under axial impact load has been analyzed by low1. Speed axial impact experiments and numerical simulation. The main work and the conclusions are as follows:1.Employing DHR-9401falling weight impact test machine, a series of experiments with cylindrical shells of same thickness, same diameter while different length under low velocity axial impact were conducted. Most of the cylindrical shells yielded expected crinkle. Using5115force sensor, both counter force of impact ends and reflect ends were recorded, and the force-time diagrams were gained. When the impact time was about2ms, the average value of the impact force was30-60kN.2.Finite element analysis program ANSYS/LS-DYNA was used to model and simulate corresponding experimental conditions, and the counter-forces of both ends of the cylinder shells are obtained. The results showed that the numerical simulations were in good agreement with experimental results. In the case of local buckling, shells showed the plastic status. Then, shell vibrated, after the elastic unloading, until stationary on the basis of plastic deformation. When the impact velocity was2.57m/s, and the shell length was168mm, overall instability of the cylindrical shell occurred, and both ends were in the plastic state.