Experiments and numerical simulations on low cycle ductile damage and failure under shear loading conditions

Ductile damage is an irreversible process that may appear during the service life of engineering structures, resulting in the degradation of material elastic behavior. Its accumulation ultimately leads to failure. An advanced phenomenological cyclic plastic-damage continuum model is employed to predict material behavior under reverse loading conditions. The Bauschinger effect, stress differential effect, and non-hardening effects are taken into account to more accurately capture plastic and damage deformations. In this context reverse cyclic shear loading is of special interest and corresponding experiments can be conducted with specially designed specimens on a standard testing device. For this loading scenario stress triaxialities remain nearly constant with values of approximately 0 during load reversal. Moreover, this shear loading sequence influences the material behavior at both macro- and micro-levels. Thus, a series of novel reverse cyclic shear experiments is realized to analyze this influence in detail. The digital image correlation technique records the deformations and changes in strains during the experiments, and selected fracture surfaces are examined by scanning electron microscopy to verify the damage and fracture mechanisms. The numerical results regarding load-displacement curves and strain fields are compared with the experimental ones.