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...

We consider the buckle-driven delamination of biaxially compressed thin films. Telephone-cord-like patterns observed in experiments are explained as a result of the buckling behavior of the film. We perform a stability analysis of a straight blister. A mechanism of instability causing undulations in an advancing finger of delamination is pointed out, which we claim to be the basic phenomenon ex...

In this paper fracture surface of the fatigue delamination have been investigated. Fatigue delamination tests were performed on the crabon/epoxy under different stress ratios. Samples were cut from the DCB specimens and analyzed in Laser Confocal Scanning Microscope. The analysis was used to measure the roughness values. Different fractographic features observed in the study are discussed.

APPROACH: Buckling driven delamination is difficult to control in experiments. Thus, the present study relies on numerical simulations using geometrically nonlinear finite element analysis as well as the softening foundation model, which is an adaptation of Winkler elastic foundation. Delamination fracture is modeled by a cohesive crack model. Dimensionless variables are used to cover the entir...

Delamination is one of the most common failure modes in composite structures. In particular, when the laminated composites are subjected to compressive loads, delamination becomes a constraint in the design process. In this study, the system is modeled as a plate supported by an elastic foundation. The elastic adhesive layer between the buckled sublaminates is represented by some parallel sprin...

A new polymer composite material composed of a fibre reinforced filler and two types matrices: thermosetting (epoxy) elastomeric (organosilicon) is introduced. The main purpose the matrix stress relaxation slowdown prevention crack growth in under dynamic loads, including bending delamination. In this study, finite element model such developed its stress-strain state calculated depending on ela...

A ``mutual integral'' approach is used to calculate the mixed-mode stress intensity factors for a free-edge delamination crack in a laminate under tensile loading conditions. This ``mutual integral'' approach, for generalized plane strain conditions, is based on the application of the path-independent J integral to a linear combination of three solutions: one, the problem of the laminate to be ...

The characteristics of carbon fibre reinforced laminates had widened their use, from aerospace to domestic appliances. A common characteristic is the need of drilling for assembly purposes. It is known that a drilling process that reduces the drill thrust force can decrease the risk of delamination. In this work, delamination assessment methods based on radiographic data are compared and correl...

Beside the twist drill, the effects of various drill geometries were rarely discussed in analytical fashion. This study presents a comprehensive analysis of delamination in use of various drill types, such as saw drill, candle stick drill, core drill and step drill. In this analysis, the critical thrust force at the onset of delamination is predicted and compared with the twist drill. © 2003 El...