Methods for Measuring the Crack Length in Rubbery Pure Shear and Sent Specimens

Abstract

Abstract A new approach for measuring crack length, which can be used for automization of fatigue test of rubber materials, is described. The crack length in the pure shear and SENT(Single Edge Notched Tension) specimens is evaluated from the variation of the peak loads under a constant cyclic displacement. For the pure shear specimen, a simple equation to give the crack length was derived from elementary consideration of the deformation pattern. The equation was applied to two constitutive models to simulate the hyperelastic behavior. It was experimentally proven that the crack length can be measured well. For the SENT specimen, an equation to give the crack length was derived from dimensional analysis. The function was assumed to be separated as the product of the deformation and geometry functions. Experiments were performed to prove the validity of the separation and to evaluate the details of the function.