Interfacial fracture toughness and cyclic fatigue-crack growth properties of joints made from 99.5% pure alumina partially transient liquid-phase bonded using copper/niobium/copper interlayers have been investigated at both room and elevated temperatures, and assessed in terms of interfacial chemistry and microstructure. The mean interfacial fracture toughness, Gc, was found to decrease from 39...

The plane problem of a crack terminating at the interface of a bimaterial piezoelectl:ic, and loaded on its fa.ces, is treated. The emphasis is placed on how to transform this problem into a non-homogeneous Hilbert problem. To make the derivation tractable, the concept of the axial conjugate is introduced and related to the complex conjugate. The angle between the crack line and the interface m...

In order to design composites and laminated materials, it is necessary to understand the issues that govern crack deflection and crack penetration at interfaces. Historically, models of crack deflection have been developed using either a strength-based or an energy-based fracture criterion. However, in general, crack propagation depends on both strength and toughness. Therefore, in this paper, ...

The problem of crack deflection in bimaterial systems is considered in this paper. The material combinations may be of piezoelectric-piezoelectric, or one is piezoelectric and the other is not. Based on the Stroh formulation for anisotropic material, Green’s functions for various bimaterial combinations are presented within the framework of two-dimensional electroelasticity, allowing the crack ...

The dynamic fracture behavior of layered architectures is experimentally studied. Specifically, crack penetration, trapping, and branching at an interface are examined. A newly introduced optical technique called Digital Gradient Sensing (DGS) that quantifies elasto-optic effects due to a non-uniform state of stress is extended to perform full-field measurements during the fracture event using ...

Dynamic crack propagation in a unidirectional carbon/epoxy composite is studied through finite element analyses of asymmetric impact (shear loading) of a rod against a rectangular plate. A finite deformation anisotropic visco-plastic model is used to describe the constitutive response of the composite. Crack propagation is simulated by embedding zero thickness interface element along the crack ...

This paper investigates the role of material properties on crack path selection in adhesively bonded joints. First, a parametric study of directionally unstable crack propagation in adhesively bonded double cantilever beam specimens (DCB) is presented. The alternating crack trajectories in specimens of various material systems are simulated using the finite element method and the results indica...

A detailed experimental and numerical investigation has been performed to validate large scale numerical simulations of dynamic crack propagation, branching, deflection, and penetration at interfaces in brittle homogeneous materials. High-speed photography in conjunction with the dynamic photoelasticity has been used to observe real-time failure mode transition mechanism at the interfaces. Wedg...