Rapid fatigue evaluation of additive manufactured specimens: Application to stainless steel AISI 316L obtained by laser metal powder bed fusion

Abstract

Laser powder bed fusion additive manufacturing is a promising technology for manufacturing components in many industrial applications. These components are often subjected to cycling loading and there are concerns about their fatigue performance due to inherent anisotropy, defects, and surface roughness. However, conventional fatigue assessment is time-consuming and expensive. Consequently, several attempts have been made in the last decades to reduce the time and cost associated with these tests by introducing the concept of rapid fatigue testing. Most of these accelerated methods necessitate advanced laboratory equipment and high-precision tests. Recently, a novel approach to rapid fatigue assessment, the stiffness method, has emerged, based on evaluating damage accumulation during the test. This method has been successfully applied and validated across a wide range of wrought metal sheets. In this study, the stiffness method is deployed to evaluate the fatigue performance of additively manufactured stainless steel AISI316L. The results are compared with predictions of the empirical model based on Murakami's approach and the conventional staircase method. A good agreement is obtained between both approaches, showing the stiffness method can estimate the fatigue limit of additive manufacturing specimens in a reliable, fast, and cost-effective way while using a significantly reduced number of tests.