Locating cracks in a solid object using acoustic emission (AE) is useful both for detecting defects during safety monitoring and basic laboratory studies of fractures. We developed an source location (ASL) method without the use velocity information with AE anisotropics plates, such as carbon fiber-reinforced polymers. Assuming that propagation unknown elastic wave constant anisotropic material...

We analyze the sensitivity to values of material parameters, layer thickness and impact speed of the plate deflection, the contact force between the impactor and the plate, the maximum length of a crack, and the energy dissipated during the low velocity impact at normal incidence of a clamped rectangular laminate by a rigid hemispherical-nosed cylinder. The laminate is comprised of layers of po...

The conditions for crack nucleation under impact loading were investigated systematically for four glasses which differ in their chemical composition, hardness and material density. Edge-on impact experiments were carried out with blunt steel cylinders within the velocity range from 20 m/s to 1000 m/s. The propagation of shock waves, of primary and secondary cracks and crack systems and the gro...

To enable the effective and reliable use of structural adhesive bonding in automotive applications, the cohesive properties of a joint need to be determined over a wide range of loading rates. In this paper, a strategy for determining these properties has been described and used to analyze a set of experimental results presented in a companion paper. In the particular system studied, a crack gr...

Pulsed infrared laser irradiation was used to positively identify small fatigue cracks on the surface of fatigue damaged Ti–6Al–4V specimens. The resulting transient thermoelastic deformation perceptibly changes the opening of partially closed surface cracks without affecting other scatterers, such as surface grooves, corrosion pits, coarse grains, etc. that might hide the fatigue crack from ul...

We analyze a self-consistent theory of crack growth controlled by a cumulative damage variable d(t) dependent on stress history, in the quasistatic regime where the sound wave velocity is taken as infinite. Depending upon the damage exponent m, which controls the rate of damage dd/dt~sigma(m) as a function of local stress sigma, we find two regimes. For 0<m<2, the model predicts a finite-time s...

Oscillatory seismic signals arising from resonant vibrations of hydraulic fractures are observed in many geologic systems, including volcanoes, glaciers and ice sheets, and hydrocarbon and geothermal reservoirs. To better quantify the physical dimensions of fluid-filled cracks and properties of the fluids within them, we study wave motion along a thin hydraulic fracture waveguide. We present a ...

An infinite elastic medium with a planar crack is considered. The crack is subjected to the pressure of fluid injected at a point on the crack surface. Description of the crack growth is based on the lubrication equation (balance of the injected fluid and the crack volume), the equation for crack opening caused by fluid pressure on the crack surface, the Poiseuille equation related local fluid ...