Coupled fracture mode of a cracked plate under anti-plane loading

Abstract

a b s t r a c tThe existence of three-dimensional effects at cracks has been known for many years, but understanding has been limited, and for some situations still is. Despite increased understanding, three-dimensional effects are sometimes ignored in situations where they may be important. The purpose of the present investigation is to study a coupled fracture mode generated by a nominal anti-plane (Mode III) loading applied to linear elastic plates weakened by a straight through-the-thickness crack. With this aim accurate 3D finite element (FE) analyses have been performed. The results obtained from the highly accurate finite element models have improved understanding of the behaviour of through cracked plates under anti-plane loading. The influence of plate bending is increasingly important as plate thickness decreases. It appears that a new field parameter, probably a singularity, is needed to describe the stresses at the plate surfaces. Discussion on whether K III tends to zero or infinity as a corner point is approached is futile because K III is meaningless at a corner point. Calculation of the strain energy density (SED) in a control volume at the crack tip allows us to predict the most critical point through the plate thickness.

Coupled fracture modes under anti-plane loading

“…s previously pointed out [13][14][15] A corner point stress function could be expected to reduce to a Westergaard stress function as a special case, but the following argument suggests that this is impossible. The Westergaard method of stress analysis [10] makes use of complex variables in which it is assumed that i 2 = -1.…”

“…In plane displacements were applied on the cylindrical surface, corresponding to a nominal mode II stress intensity factor K II = 1 MPam 0.5 (31.62 N·mm 0.5 ). T Secondly, plates of finite thickness under anti-plane (remote nominal mode III) [14]. A square plate with a constant width equal of 100 mm has been considered.…”

“…In an attempt to resolve these an extensive finite element research programme has been carried out [13][14][15]. 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.…”

Effect of corrosion and fatigue on the remaining life of structures and its implication to additive manufacturing

“…As an important factor in failure assessments under fatigue and static loading, 3D effect has been studied in numerous researches and 3D effects in the form of stress state have been investigated for wide variety of notch geometries under various in-plane and out of plane loading conditions by considering stress concentration factors and constraint factors throughout the thickness of the specimen [48,49]. As a representative of stress state in cracked and notched components, the variations of the stress concentration factor as a function of the thickness have been studied in some recent researches by Berto and co-researchers [50][51][52][53][54][55][56]. As an interesting and effective fact, the same concept can be considered for fatigue crack growth assessment in metallic components of steel bridges with presence of natural corrosion in the material.…”

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].…”