A high fidelity delamination failure analysis was developed by combining a local failure analysis with a global fullscale finite element structural analysis to address strength and delamination failure in a single package. The methodology was demonstrated through a local threedimensional pull-off failure analysis and a geometrically nonlinear structural analysis of a five-foot composite helicop...

A new cohesive model for simulating delamination propagation in composite laminates under transverse loads. Running title: A new cohesive model for simulating delamination propagation in composite laminates 2 Abstract In this paper, we propose a new cohesive model to stably and accurately simulate the delamination propagations in composite laminates under quasi-static and low-velocity impact tr...

A shell/3D modeling technique was developed for which a local solid finite element model is used only in the immediate vicinity of the delamination front. The goal was to combine the accuracy of the full three-dimensional solution with the computational efficiency of a plate or shell finite element model. Multi-point constraints provide a kinematically compatible interface between the local 3D ...

Delamination of residually stressed thin film strips is analyzed to expose the dependence on strip width and filmysubstrate elastic mismatch. Isotropic films and substrates are assumed. The residual stress in the film is tensile and assumed to originate from mismatch due to thermal expansion or epitaxial deposition. Full and partial delamination modes are explored. In full delamination, the int...

This paper presents an experimental investigation on mode I delamination of z-pinned double-cantilever-beams (DCB) and associate z-pin bridging mechanisms. Tests were performed with three types of samples: big-pin with an areal density of 2%, small-pin with an areal density of 2% and small-pin with an areal density of 0.5%. The loading rates for each type of samples were set at 1 mm/min and 100...

Drilling of carbon fibre/epoxy laminates is usually carried out using standard drills. However, it is necessary to adapt the processes and/or tooling as the risk of delamination, or other damages, is high. These problems can affect mechanical properties of produced parts, therefore, lower reliability. Production of higher quality holes is a challenge to everyone related with composites industry...

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...

Reinhold Dauskardt Stanford University, Professor Materials Sciences and Engineering The stratum corneum (SC) is the outermost layer of the skin. Its process of reneweal is regulated by various mechanisms, including chemical and structural gradients through the SC thickness. In this study, an in vitro mechanics approach for studying the delamination behavior of SC in the direction perpendicular...

Separation of the anterior layer of the lens capsule, also known as true exfoliation and capsular delamination, has become an increasingly rare clinical finding. Although its pathogenesis is not precisely known, the condition has been associated with age, trauma, and exposure to toxins and/or to thermal radiation. An association with occupational infrared radiation exposure was accepted after E...

Little is known about how intercellular communication is regulated in epithelial cell clusters to control delamination and migration. We investigate this problem using Drosophila border cells as a model. We find that just preceding cell cluster delamination, expression of transmembrane immunoglobulin superfamily member, Fasciclin 2, is lost in outer border cells, but not in inner polar cells of...