When a femtosecond laser pulse is focused inside a LiF single crystal, four cracks are generated in the <100> directions from the photoexcited region. The time-resolved observation have elucidated that the tensile stress in the laser induced stress wave induces the generation and propagation of the cracks. In this study, to investigate the possibility of control of laser induced cracks inside s...

This paper is aimed at presenting a partition of unity method for the simulation of three-dimensional dynamic crack propagation. The method is a variation of the partition of unity ®nite element method and hp-cloud method. In the context of crack simulation, this method allows for modeling of arbitrary dynamic crack propagation without any remeshing of the domain. In the proposed method, the ap...

The propagation of an interfacial crack front along the weak plane of a thin film stack is considered. A simple patterning technique is used to create a toughness contrast within this perfectly two-dimensional weak interface. The transparency of the specimens allows us to directly observe the propagation of the purely planar crack obtained during a DCB (Double Cleavage Beam) test. The effect on...

This paper presents a stochastic model of fatigue crack propagation in ductile alloys that are commonly encountered in mechanical structures and machine components of complex systems (e.g. aircraft, spacecraft, ships and submarines, and power plants). The stochastic model is built upon a deterministic state-space model of fatigue crack propagation under variable-amplitude loading. The (non-stat...

This paper deals with the implementation of an efficient Arbitrary Lagrangian Eulerian (ALE) formulation for the three dimensional finite element modeling of mode I self-similar dynamic fracture process. Contrary to the remeshing technique, the presented algorithm can continuously advance the crack with the one mesh topology. The uncoupled approach is employed to treat the equations. So, each t...

We report a novel mode of quasi-static oscillatory crack propagation when a cutting tip of moderately large width is driven through a thin brittle polymer film (Roman [1] , Ghatak [2]). Experiments show that the amplitude and wavelength of the oscillatory crack paths scale linearly with the width of the cutting tip over a wide range of length scales but are independent of the width of the sheet...

A technique to heal a fatigue crack in austenitic stainless steel SUS316 by applying a controlled, high-density pulsed current was developed. A surface-activated pre-coating (SAPC), which eliminates the oxide layer and coats a Ni film on the crack surface, was used to improve the adhesion between crack surfaces. Cracks were observed by scanning electron microscopy before and after the applicati...

Bamboo, as a natural hierarchical cellular material, exhibits remarkable mechanical properties including excellent flexibility and fracture toughness. As far as bamboo as a functionally graded bio-composite is concerned, the interactions of different constituents (bamboo fibers; parenchyma cells; and vessels.) alongside their corresponding interfacial areas with a developed crack should be of h...

Abstract: The effect of phase development on peel strength of alumina-copper metalized joint has been investigated. The alumina-copper joint was prepared in three stages. The alumina substrate was, first, metalized at 1500°C in H2-furnace by a new formulation. In the second step, a nickel layer was electroplated on the metalized layer with approximately 10µm thickness. Finally, copper strip...