Coupled fracture modes of discs and plates under anti‐plane loading and a disc under in‐plane shear loading

Abstract

Three-dimensional effects near crack tips have been deeply investigated in the past, but the topic is still ongoing and under investigation. However, the understanding is in some cases limited, and the problem requires further attention. Three-dimensional effects are in fact neglected in situations where they may play an important role. The main aim of this review paper is to summarise some recent results of a study carried out on the coupled in-plane fracture mode induced by a nominal anti-plane (mode III) loading applied to plates and discs weakened by a straight crack. Only linear elastic conditions are considered herein. The results derived by a large bulk of finite element models allow a better understanding of coupled modes generated by anti-plane loading. The influence of plate/disc bending on three-dimensional stress fields is considered in the investigation, showing that it becomes non-negligible as the thickness decreases. Some considerations on the trend of KIII as the corner point is approached are also part of this paper. In addition, the trend of the strain energy density (SED) in a volume surrounding the crack tip is shown and commented on. This parameter allows the precise determination of the weakest point of the component through the thickness becoming a useful tool. Some new results for a disc under in-plane shear loading are included. These results clarify the influence of disc bending under anti-plane loading

Corner point singularities under in-plane and out-of-plane loading: a review of recent results

“…At the present state of the art the results obtained show that Bažant and Estenssoro's solution for corner point singularities is incomplete (Pook et al 2014(Pook et al , 2016. For mode I loading the analysis successfully predicts the critical angle at which a crack front intersects a free surface.…”

“…In an attempt to resolve paradoxes and inconsistencies an extensive finite element research program has been carried out (Pook et al, 2014(Pook et al, , 2016. The purpose of the present paper is to present some of the results obtained, and also to present a possible approach to resolution of paradoxes and inconsistencies.…”

“…The applied displacements correspond to a nominal mode III stress intensity factor KIII = 1 MPam 0.5 (31.62 N·mm 0.5 ). Recently, results have been obtained for in-plane shear loading of a disc, t/a = 1 (Pook et al 2016). In plane displacements were applied on the cylindrical surface, corresponding to a nominal mode II stress intensity factor KII = 1 MPam .…”

A generalised approach to rapid finite element design of notched materials against static loading using the Theory of Critical Distances

“…In particular, in the vicinity of a stress concentrator the actual linearelastic stress distribution varies across the thickness, with this holding true both under normal [40,42,43] and shear loading [40,44,45]. Under these circumstances, the problem is that the maximum value of the local stress is away from the surface [40].…”

Experimental and FE Modeling of Mixed-Mode Crack Initiation Angle in High Density Polyethylene

“…et al [26], Berto et al [27] and Campagnolo et al [28] to assess the fracture strength of different materials, characterized by different control volumes and subjected to wide combinations of static loading [29][30][31][32]. Moreover, it has been successfully employed for the fatigue strength of welded joints [33][34] and notched components [35,36].…”