Shape optimization of continuous structures under impact load

Most of the structures in civil engineering are usually designed only for static load, wind load, earthquake load and vehicle loads, but more lately there has been an awareness raising that some structures must be designed to withstand both dynamic (impact) loads and static loads. Especially after increasing terrorist activates in a new day. Many researchers and engineers are studying the behavior of the structures under impact load and trying to improve the structures in different ways. Study on the behavior of structure and optimization shape of the structure under impact load is important for many designs, not only building structures such as automobile particles, military sector and for other mechanical design because optimization shape means reducing the weight of the structure. This research deals with the determination of the stress velocity under impact loading and optimization of the structures by using evolutionary structural optimization (ESO) under low impact loading, and in this research the effect of the material properties and impact velocity on stress velocity is studied. Determination of explicit time integration and time step (minimum time step (tmin) and maximum time step (tmax) also be studied. The aim of this study is to improve the structures under impact loading by the determination of a suitable optimization shape for the structure. Structures were modeled by macro program in the ANSYS-APDL/LS-DYNA CODE by a specific dimension. The main structure in this study is the beam with dimension (2000*500*200) mm for length, thickness and width respectively. Different programs were written and modeled Analyzing the beam under impact loading for different properties to find the effect of material properties on the behavior of the structure (beam) under impact load. Determination of optimization shape for the different structures (beam, cantilever beam, slab and cantilever slab.) under impact loading, then finding the volume, maximum stress and minimum stress of the structures for the real shape and optimization shape, then comparing the results for both situations.