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...

A comparison is made of the mechanochemical activation of three low- and one high-defect kaolinite using a combination of X-ray diffraction, thermal analysis, and DRIFT spectroscopy. The effect of mechanochemical alteration of the kaolinites is greater for the low-defect kaolinites. The effectiveness of the mechanochemical treatment is represented by the slope of the d(001) peakwidth-grinding t...

An experimental setup is designed to detect composite delamination damage based on ultrasonic infrared thermography. The ultrasonic infrared thermography system is composed by ultrasonic excitation system, infrared thermal imager and data acquisition system and two damaged composite plate specimens are produced in the experiment. The image processing methods including thresholding, filters, edg...

Ultrasonic testing using couplants is most popular technique for non destructive testing of solid materials. In the most non – destructive evaluation tasks such as investigation of materials whose properties may be changed by liquid contact this technique can not be used. Use of contact technique can be restricted for complex geometry structures. Also, liquid couplants cannot be used when mater...

Delamination is a type of representative damage in composite structures, severely degrading structural integrity and reliability. The identification of delamination is commonly treated as an issue of nondestructive testing. Differing from existing studies, a hybrid optimization algorithm HOA , combining particle swarm optimization PSO with simplex method SM , is proposed to identify delaminatio...

C-mode scanning acoustic microscopy (C-SAM) is a non-destructive inspection technique showing the internal features of a specimen by ultrasound. The C-SAM is the preferred method for finding “air gaps” such as delamination, cracks, voids, and porosity. This paper presents evaluations performed on various advanced packages/assemblies especially flip-chip die version of ball grid array/column gri...

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...

A three-dimensional spectral element method SEM was developed for analysis of Lamb wave propagation in composite laminates containing a delamination. SEM is more efficient in simulating wave propagation in structures than conventional finite element method FEM because of its unique diagonal form of the mass matrix. Three types of composite laminates, namely, unidirectional-ply laminates, cross-...

Layered composites subject to impacts can fail by delamination, i.e. by debonding between laminae, if the stress waves cause damaging phenomena to take place mainly within the resin-enriched interlaminar phases. To simulate delamination at the structural level, processes dissipating energy are lumped onto fictitious zero-thickness interlaminar surfaces, and softening interface constitutive laws...