Characterisation of the anisotropic response of wire and arc additively manufactured stainless steel

Abstract

In contrast to conventional structural steel and stainless steel, wire and arc additively manufac-tured (WAAM) material can exhibit a strongly anisotropic response. To investigate the degree of anisotropy in WAAM sheet material, data obtained from tensile tests on machined and as-built stainless steel coupons are utilised. The WAAM material was tested in three different loading di-rections relative to the deposition direction and the response was captured using digital image correlation; a summary of the key results is presented. In the elastic range, the observed mechan-ical response is characterised using an orthotropic plane stress material model, which requires the definition of two Young’s moduli, the Poisson’s ratio and the shear modulus. Good agreement be-tween the test results and the theoretical predictions based on the orthotropic material model is demonstrated. In the inelastic range, to describe the anisotropic yielding of the material, the well-known Hill’s criterion utilising the 0.2% proof stresses is employed. Overall, the elastic and inelas-tic properties of the studied material are shown to vary significantly with the direction of loading.