In this paper, the data reduction equations for common delamination toughness tests are rederived for use with specimens which have bonded doublers. The common toughness tests considered here are the double cantilever beam (DCB) for mode I toughness; the end notch flexure (3ENF) and 4 point ENF (4ENF) for mode II toughness; and the mixed mode bending (MMB) test for testing under combined mode I...

Channeling cracks in brittle thin films have been observed to be a key reliability issue for advanced interconnects and other integrated structures. Most theoretical studies to date have assumed no delamination at the interface, while experiments have observed channel cracks both with and without interfacial delamination. This paper analyzes the effect of interfacial delamination on the fractur...

The effects of temperature and loading rate on delamination growth were studied. The delamination fracture toughness of IM7/K3B was measured at 149°C, 177°C, and 204°C. At each temperature the tests were performed with a variety of loading rates so that the delamination initiated over the range of time from 0.5 sec to 24 hrs. The double cantilever beam (DCB) test was used to measure fracture to...

The orientation dependence of Charpy toughness has been investigated in API-X80 linepipe steel. The occurrence of delamination and preferential alignment of {100} cleavage planes are found to contribute to the observed anisotropy in Charpy properties. Delamination is also related to the presence of banding in the hot–rolled alloy, and the additional plasticity it entails during the process of f...

In this chapter some of the standard procedures for delamination testing of unidirectional polymer composites will be examined. The main objective is to explore the possibilities of applying the standard testing methods to interlayer toughened composites and to establish parameters which may influence fracture toughness measurements. Existing standards for mode I and mode II delamination testin...

(2005) Fracture behavior of polyetherimide (PEI) and interlaminar fracture of CF/PEI laminates at elevated temperatures. Abstract To investigate effects of environmental temperature on fracture behaviour of a polyetherimide (PEI) thermoplastic polymer and its carbon fibre (CF/PEI) composite, experimental and numerical studies were performed on compact tension (CT) and double cantilever beam (DC...

Ceramic coatings deposited on metal substrates generally develop significant compressive stresses when cooled from the temperature at which they are processed as a result of thermal expansion mismatch. One of the main failure modes for these coatings is edge delamination. For an ideally brittle interface, the edge delamination of a compressed thin film involves mode II interface cracking. The c...

A finite element (FE) model is developed to investigate mode I delamination toughness of z-pin reinforced composite laminates. The z-pin pullout process is simulated by the deformation of a set of non-linear springs. A critical crack opening displacement (COD) criterion is used to simulate crack growth in a double-cantilever-beam (DCB) made of z-pinned laminates. The toughness of the structure ...

Mode II delamination toughness of z-pin reinforced composite laminates is investigated using finite element (FE) method. The z-pin pullout process is simulated by the deformation and breakage of non-linear springs. A critical shear stress criterion based on linear elastic fracture mechanics is used to simulate crack growth in an end-notched-flexure (ENF) beam made of z-pinned laminates. The mod...