Estimation of three‐dimensional stress intensity factor for structural ‘T’ details

Three‐dimensional (3D) opening mode stress intensity factors (SIFs) for structural steel‐welded ‘T’ details were investigated by the finite element method. A 3D shape‐dependent correction factor is proposed for semi‐elliptical surface cracks. The aspect ratio (a/c) of a semi‐elliptical crack plays a key role in the approximation of 3D‐SIF values, and in the present study, it was estimated for a 3D crack analysis. The estimated 3D‐SIF was determined through a correlation between the a/c ratio and the two‐dimensional SIF for semi‐elliptical cracks in the thickness direction adjacent to the web‐flange junction of a welded ‘T’. The resulting equation can be used to estimate the 3D‐SIF values from the two‐dimensional SIF without much ambiguity.     

Discussion on ‘influence of applied electric field and mechanical boundary condition on the stress distribution at the crack tip in piezoelectric materials’

Using the finite element results, Kumar and Singh [3] have amazingly pointed out that the applied electric field can strongly influence the mechanical boundary condition. Due to the importance of the applied electric field, the applications of various kinds of electric boundary conditions have been discussed in order that one can correctly make use of both electric and mechanical boundary conditions. The influence of the applied electric field has also been proved on the basis of analytic method.