Elastic–plastic damage prediction in notched epoxy resin specimens under mixed mode I/II loading using two virtual linear elastic failure criteria

Abstract

<jats:p> Elastic–plastic damage of a ductile epoxy resin is investigated for the first time in the configuration of semicircular bend specimen weakened by U-shaped notches under mixed mode I/II loading conditions. U-notched specimens are prepared from the characterized epoxy material with different notch rotation angles and notch tip radii. Load-carrying capacities of the U-notched specimens are experimentally obtained by performing fracture tests under various combinations of mode I and mode II loading. The reformulated Equivalent Material Concept is employed for the polymeric material in conjunction with the maximum tangential stress and mean stress criteria to provide the theoretical predictions without any necessity for elastic–plastic analyses of their damage. Scanning electron microscopy micrographs are also taken from the fracture surfaces and utilized for realizing the micromechanical processes of damage in the tested specimens. A very good consistency is found between the experimental results and the predictions of the combined Equivalent Material Concept-maximum tangential stress criterion, as well as those of the Equivalent Material Concept-mean stress criterion. </jats:p>

A convex anisotropic damage model based on the compliance tensor

“…The tensor order of the damage variable naturally distinguishes different phenomenological damage models. Even today, the classical scalar isotropic damage variable serves as a reliable workhorse with numerous applications including cast steel with pores (Yan et al., 2020), concrete (Li and Wu, 2018), rocks (Liu et al., 2018; Xu et al., 2018), framed structures (Yang et al., 2017), unidirectional glass fiber-reinforced plastic composite plies (Sharma and Daggumati, 2020), fibrous composite laminae (Abu-Farsakh and Asfa, 2020), notched epoxy resin specimens (Rahimi et al., 2020) and steel-fiber reinforced concrete (Moradi et al., 2020).…”