METHOD FOR MEASURING DISPLACEMENT OF CRACK APERTURE IN DESTRUCTIVE TENACITY TEST

摘要

PURPOSE:To make it possible to calculate the change in the aperture at the leading end of a crack without using yield stress under a testing condition, by simultaneously measuring the displacement between two points holding a crack position therebetween at two positions changed in the distance from a crack leading end position. CONSTITUTION:A jig 2 is mounted to the surface of a test piece 1 at the position of a notch 1-1 and, thereafter, load P is applied to the test piece 1 from the side opposite to the notch 1-1. When the load P exceeds the endurable value of the test piece 1, a crack 1-2 is generated at the leading end of the notch 1-1. When the load P was applied to the test piece 1, displacements V1, V2 between two points respectively holding the crack position therebetween are simultaneously measured by the displacement measuring apparatuses 2-1, 2-2 mounted to the jig 2. Subsequently, the displacement delta of the aperture at the leading end of the crack can be calculated from the measured values V1, V2, a crack length (a), the distance (b) up to the apparatus 2-1 and the distance (c) up to the second displacement measuring apparatus 2-2 from the apparatus 2-1 according to formula (wherein delta is the displacement of the aperture at the leading end of a crack).