Ductile Fracture in WAAM‐Fabricated High Strength Steel for Structural Applications

Abstract This study investigates the ductile fracture behaviour of coupon‐like specimens produced by Wire Arc Additive Manufacturing (WAAM) using AM70 high‐strength low‐alloy steel wire. Experimental testing under uniaxial tension and shear loading was conducted, supported by digital image correlation to capture strain fields. The material's plastic response was calibrated using a combination of true stress‐strain conversion, a weighted average model for post‐necking behaviour, and finite element simulations. Ductile damage was implemented numerically to simulate fracture, showing good agreement with experimental results in both failure mode and stress‐strain response. The AM70 WAAM material exhibited a fracture strain of 0.65 in uniaxial tension and 0.70 in shear, indicating enhanced ductility compared to high‐strength steels and previously reported WAAM references. Despite a moderate reduction in yield strength the material showed promising mechanical performance, particularly under shear‐dominated conditions. These findings suggest the suitability of AM70 WAAM components for applications requiring high deformation capacity. The validated modelling approach offers a robust basis for predicting failure, and future work will explore the application of advanced fracture models for improved accuracy across diverse loading conditions.