Mechanisms influencing the plane-strain fracture toughness behavior of commercial aluminum-lithium alloys at cryogenic temperatures are investigated as a function of microstructure and plate orientation. It is confirmed that certain alloys show a marked increase in tensile ductility and toughness with decrease in temperature, although such behavior is not found in the short-transverse orientati...

Delamination is an important concern in the context of structural behaviour of laminated composite materials. It is known that delamination can diminish the stiffness and the strength of the material and promote structural failure. Delamination onset and growth is governed by interlaminar fracture toughness of the material. Delamination propagation is frequently dominated by mode II fracture; c...

Composite materials are prone to delamination as they are weaker in the thickness direction. Carbon nanotubes (CNTs) are introduced as a multiscale reinforcement into the fiber reinforced polymer composites to suppress the delamination phenomenon. This review paper presents the detailed progress made by the scientific and research community to-date in improving the Mode I and Mode II interlamin...

This study uses observations of mechanisms from previous work (the “undamaged cone”, toughness and extent of permanent out-of-plane deformation) to examine parametrically their effects on residual compression after impact (CAI) strength using finite element models. In previous experimental work, tougher material systems exhibited up to 30% greater CAI strength for a given damage area. Based on ...

Delamination is a predominant failure mechanism in composite structures. In the present study, double cantilever beam tests were performed to investigate the effects of temperature and fiber orientation on the Mode I interlaminar fracture toughness, G I , of carbon fiber-reinforced epoxy composites, T800H/#3631. The values of G I for three kinds of laminates, [0 12 //0 12 ], [22.5/-22.5/0 8 /-2...

The demands by the semiconductors industry for high levels of integration, lower costs and a growing need for complete system solutions has led to the emergence of ”System In Package” (SIP) solutions in which ”the package is the system”. Since SIP-microsystems have multiple thin and stacked layers manufactured using different processes and materials, internal (intrinsic and/or thermal) mismatch...

The indentation of a brittle film on a ductile substrate is analysed for obtaining the interface toughness. This measurement method of adhesion provides a simple technique for sampling a small area of the interface on practical geometries with common laboratory equipment. Mechanics solutions are presented to access the interface toughness, Fc, from measurements of the applied load, delamination...

In this study, a novel numerical method is proposed for determination of mode-I interlaminar fracture toughness, GIc, in multi-directional (MD) double cantilever beam (DCB) specimens using fracture properties of unidirectional DCB specimens. Two factors, β and Dc are defined to minimize the undesirable effects on strain energy release rate. β describes the difference between maximum and average...

Thin film delamination can occur when the stored elastic energy per unit area in the film due to the residual stress exceeds the interfacial toughness. Telephone cord morphology is commonly observed in delaminating thin films under compressive stresses. Here, the biaxial film stress is partially relieved by film buckling in the direction perpendicular to the telephone cord propagation, and by "...

Interlaminar fracture mechanics has proven useful for characterizing the onset of delaminations in composites and has been used with limited success primarily to investigate onset in fracture toughness specimens and laboratory size coupon type specimens. Future acceptance of the methodology by industry and certification authorities however, requires the successful demonstration of the methodolo...