In this paper, we describe the second part of an experimental investigation concentrating on the study of the effects of impact speed and interfacial bond strength on the dynamic failure of model sandwich structures. Results show that even small variations in impact speed and bond strength substantially influence the initiation behavior of delamination (location and nucleation time) and lead to...

Delamination plays a pivotal role during normal development and cancer. Previous work has demonstrated that delamination and epithelial cell movement within the plane of an epithelium are associated with a change in cellular phenotype. However, how this positional change is linked to differentiation remains unknown. Using the developing mouse pancreas as a model system, we show that β cell dela...

A finite-element-based toolset has been developed to simulate arbitrary evolution of 3-D, geometrically explicit, interlaminar delaminations in composite structures. A new energy-based growth formulation uses the virtual crack extension (VCE) method to predict point-by-point growth along the delamination front. The VCE method offers an accurate and computationally efficient means to extract bot...

Dead cells in most epithelia are eliminated by cell extrusion. Here, we explore whether cell delamination in the amnioserosa, a seemingly stochastic event that results in the extrusion of a small fraction of cells and known to provide a force for dorsal closure, is contingent upon the receipt of an apoptotic signal. Through the analysis of mutant combinations and the profiling of apoptotic sign...

In situ synchrotron X-ray computed micro-tomography and digital volume correlation (DVC) were utilised to understand the failure mechanisms at room temperature 1050 °C of two Nextel™720/alumina oxide-oxide ceramic-matrix composites (CMCs), termed materials A B, sintered respectively 1200 ~1250 °C. At both test temperatures, three-point-bending strengths ~55–58 MPa for material ~94–100 B. Damage...

Delaminations in composite laminates resulting from impact events may be accompanied by minimal indication of damage at the surface. As such, inspection techniques are required to ensure defects are within allowable limits. Conventional ultrasonic scanning techniques have been shown to effectively characterize the size and depth of delaminations but require physical contact with the structure. ...

Over the past few decades, there has been a considerable interest in the use of distributed optical fibre sensors (DOFS) for structural health monitoring of composite structures. In aerospace-related work, health monitoring of the adhesive joints of composites has become more significant, as they can suffer from cracking and delamination, which can have a significant impact on the integrity of ...

This paper is concerned with a progressive failure analysis methodology for fiber reinforced composite laminates combining various analytical models designed for investigating failure mechanisms at different length scales. The methodology here employs a fundamental mechanism based approach to predict failure or damage initiation with strong coupling between the multiple length scales. The discr...