Low cycle fatigue modelling of cellular materials produced by laser-powder bed fusion

Abstract

A finite element (FE) modelling approach is developed to reproduce the cyclic elastoplastic response and to assess the low cycle fatigue (LCF) life of two cellular materials (strut-based, gyroid) investigated in a previous experimental campaign. The cyclic response of different FE models (unit cell, one layer structure) is compared in terms of computational cost and modelling accuracy. The most satisfactory model is further updated based on the actual relative density of fabricated cellular materials. The LCF assessment exploits a volume-based strain energy density (SED) criterion, calibrated after comparing static properties of strut-based and bulk materials. The cyclic elastoplastic response is well reproduced for both cellular materials, whereas the estimated fatigue lives are in closer agreement for the gyroid structure than the strut-based one.

Keywords

• Cellular materials
• Low cycle fatigue
• Cyclic elastoplastic behaviour
• Finite element
• Laser-powder bed fusion
• 316L stainless steel