Dynamic strength of stainless steel subjected to cyclic impact loading of strong motion. Influence evaluation of strain rate

The aim of this study is to reveal the effects of strain velocity caused by dynamic strain under earthquake for the material strength of nuclear equipment and structures quantitatively. From the obtained results, it can be clarified how degree the strain velocity contributes to seismic safety margin in the equipment and structures. This paper addresses the fracture modes of stainless steel and the effect of strain velocity caused by the cyclic impact loading such as seismic motions. The ductile type and brittle type of fracture modes appeared in excess large loading and relative large loading, respectively. The two fracture modes took turns without the transition state rapidly. Compared based on the strain amplitude, the numbers of cycles to fracture in the different stain velocities were the same. Within the extent of the experiment, it was found the fracture behavior of stainless steel did not depend on the strain velocity. (author)