Transverse singular effects in V-shaped notches stressed in mode II

Abstract

The concept of a stress singularity is a cornerstone of modern fracture mechanics. A new mode of stress singularity, the out-of-plane singular mode or K (O) mode, was recently identified for V-shaped notches subjected to in-plane loading. This new mode is coupled with the shear mode and related to Poisson's effect. The previous studies based on the first order plate theory focused on the derivation of a characteristic equation describing the strength of this singularity and provide no information regarding the intensity, extent and relevance of this mode to practical problems. This paper aims to fill this gap. The approach utilises the 3D finite element method and a standard regression technique for characterisation of the notch singular modes. A comprehensive study of the influence of Poisson's ratio, plate thickness and notch opening angle on the value of the notch stress intensity factor associated with this mode is conducted for infinite plates. Additionally, to demonstrate the relevance of this new singular mode to practical problems an investigation of the out-of-plane mode and associated three-dimensional effects are presented for the case of a welded lap joint. Main areas of further research are also identified

A disk-shaped domain integral method for the computation of stress intensity factors using tetrahedral meshes

“…Such behavior is inconsistent with the free boundary conditions and zero anti-plane shear stress at the free surfaces. This inconsistency has been noticed by Harding et al (2010); Kotousov et al (2010), as the K III values they computed using the stress extrapolation method deviates from the ones obtained by Nakamura and Parks (1989) for the points very close to the corner point. The reason for this inconsistency has not been investigated previously.…”

Evaluation of Fatigue Crack Front Shape for a Specimen with Finite Thickness

“…6 is developed. From linear elastic three-dimensional finite element analysis the distribution of the maximum stress intensity factors along the thickness direction under the maximum loading conditions are obtained in accordance with the techniques developed in Harding et al [21] and Kotousov et al [22].…”

Comportamento a fatica dei giunti saldati in funzione della densità di energia di deformazione locale: influenza dei campi di tensione singolari e non singolari

“…Tali singolarità potrebbero avere pratiche conseguenze sulle proprietà di resistenza a fatica di alcune geometrie di giunti saldati [29]. Si ritiene utile qui inquadrare analiticamente il problema, chiarendo le conseguenze sulle distribu-zioni di tensione relative ad alcune geometrie di interesse applicativo.…”

“…Figura 9: Rappresentazione schematica dell'effetto 'out-of-plane'; sistema di coordinate utilizzato nella trattazione analitica (simbologia in accordo con le referenze [27][28][29]). …”

“…L'espressione di destra dà invece il modo 'out-of-plane'. Si noto come tale espressione coincida perfettamente con l'espressione che esprime gli autovalori di modo III [29]. Per illustrare la formulazione analitica, si consideri il giunto a sovrapposizione di Fig.…”