Validation and Verification of Fatigue Assessment using FE Analysis: A Study Case on the Notched Cantilever Beam

Abstract

The fatigue phenomenon caused by cyclic loads on the mechanical structures needs to be considered during the design process of any engineering structures. Cyclic loads that are even below yield strength can cause failure if they are repeated continuously in a certain period of time. Estimating fatigue life accurately is very important task, which various variables must be taken into calculation in order to avoid catastrophic failure. There are two methods that can be used to predict fatigue life, i.e., conducting experiment tests and using Finite Element Method (FEM)-based simulation. FEM has the advantage that it is possible to identify stress distribution, capable to visualize the failure mechanisms in certain areas, can reduce development time and development cost, facilitate shape optimization, and improve product quality. Nevertheless, FEM needs to be validated to maintain its accuracy in analyzing fatigue phenomena. In this study, a cantilever beam with notched angle 90° and height of 25 mm has been analyzed using fatigue tool on ANSYS. The aims is to present reliable validation reference by considering stress life approach in calculation. The applied material is a structural steel with modulus elasticity of 200 GPa, Poisson’s ratio of 0.3 and yield strength of 250 MPa. Applied load of 10 kN assuming zero based conditions and mean stress theory used are Goodman, Soderberg, Gerber, and ASME Elliptical. Based on the convergence analysis, the optimum mesh size is 4 mm with approximately 90, 322 elements on the specimen geometry. The extended discussion is directed to the total deformation, fatigue life, fatigue safety factor, and fatigue damage.