A method for measuring compliances and crack length by strain gauge and 3D finite element calculation

Abstract A method for determining compliances and crack lengths of round CT specimen geometries (RCT) by measuring the notch opening displacement (NOD) with strain gauges, combined with 3D finite element calculations to correlate the NOD to the loading point displacements, is presented. The method has been verified for tungsten and it is shown that measured and calculated compliances are in excellent agreement. A general equation is presented correlating compliances and NOD which allows to implicitly determine crack lengths by simply measuring the NOD of RCT specimens.