Numerical determination of dynamic stress concentration factors for an axially loaded strut with elliptical and notch discontinuities

Numerical modeling, simulation, and analysis of axial struts (with geometrical discontinuities) subjected to dynamic loading conditions is the focus of this paper. Understanding how geometrical discontinuities influence the stress distribution within a structural member is critical for design applications. Furthermore, understanding how axial struts perform under dynamic loading conditions is critical in the design of automobiles, airplanes, and a large number of potentially dynamically loaded structures. A large amount of research investigating static loading conditions of struts with geometrical discontinuities has been conducted. With the development of finite element codes, numerical dynamic analyses can be completed much easier and at much lower costs than would occur for experimental methods. In this research finite element simulations were conducted on struts with centrally located elliptical holes as well as struts with circular notches subjected to an impact load. The stress distributions of the models were studied to determine the maximum stress state for each geometric configuration. This information was used to determine the dynamic stress concentration factor for each configuration. The dynamic stress concentration factor is plotted as a function of time and three-dimensional surface plots are shown, illustrating how the dynamic stress concentration factor varies with discontinuity geometry. It is shown that the dynamic stress concentration factor varies with time more significantly for discontinuities that minimize the nominal cross section of the strut.