Use of strain gages for determining generalized stress intensity factors of sharp V-notched plates under transverse bending

Abstract

A strain gage method has been developed for determining the generalized stress intensity factors (GSIFs) of sharp V-notched plates subjected to transverse bending. The study is based on Mindlin’s theory of plate bending. The bisector of the notch opening angle is inclined to the edge of the plate, and the mixed mode loading is created simultaneously. The singular strain fields around the notch tip including the non-singular terms are derived in terms of the GSIFs. These strain fields of dominant terms do not coincide with those of the plane problem. The crack strain fields, however, are coincident with those of the plane problem, if we take a limiting value in the notch strain fields obtained. In order to separate the mixed-mode GSIFs, two strain gages with five element grids are severally positioned along the two lines extending from the bisector of the notch, and a simple procedure to determine the GSIFs for each mode is presented. Experiments on the specimens in strip form with various notch opening angles and inclination angles as well as an inclined crack in rectangular plates are carried out to compare with the results of finite element analyses according to Mindlin’s plate theory. It is shown that the reasonable agreement is obtained between them.