A novel approach for determining the stress intensity factor for cracks in multilayered cantilevers

Abstract

In modern engineering applications, multilayered structures are extensively used. The material property variations between the layers affect the fracture behavior of the multilayer by the reduction or enhancement of the crack driving force. This “material inhomogeneity effect” complicates the determination of the stress intensity factor of cracks in multilayered components, and a combination of experimental measurements and numerical computations was necessary to determine correctly the fracture toughness. A procedure is presented in this paper, which enables the simple determination of the stress intensity factor from analytic relations, without numerical analysis. These relations are valid for multilayered cantilevers and multilayered three-point bend specimens with variations of the Young’s modulus. The procedure can be also used for the design of tough multilayered composites. The procedure is verified for different multilayer configurations by finite element computations and validated with the help of experimental results from literature.