In this article, high-speed photographic investigations of the dynamic crack initiation and propagation in several inorganic glasses by the impact of small spherical and conical projectiles are described. These were carried out at speeds of up to approximately 2×10(6) frames s(-1). The glasses were fused silica, 'Pyrex' (a borosilicate glass), soda lime and B(2)O(3). The projectiles were 0.8-2 ...

The intrinsic coupling between the mechanical and the electric _elds assigns a unique feature for the fracture in a piezoelectric solid[ We model the kink of a crack by continuous distribution of edge dislocations and electric dipoles[ The problem admits an approach based on the Stroh formalism[ A set of coupled singular integral equations are derived for the dislocation and electric dipole den...

This paper investigates the role of material properties on crack path selection in adhesively bonded joints. First, a parametric study of directionally unstable crack propagation in adhesively bonded double cantilever beam specimens (DCB) is presented. The alternating crack trajectories in specimens of various material systems are simulated using the finite element method and the results indica...

Ductile-brittle fracture transition was investigated using compact tension (CT) specimens from -70 o C to 40 o C for a carbon steel. Large deformation finite element analysis has been carried out to simulate the stable crack growth in the compact tension (CT, a/W=0.6), three point-point bend (SE(B), a/W=0.1) and centre-cracked tension (M(T), a/W=0.5) specimens. Experimental crack tip opening di...

Continuum mechanics predicts that the propagation speed of non-equilibrium information in solids is limited by the longitudinal wave speed, so is crack propagation. However, solids are essentially discrete systems. In this paper, via theoretical analysis and numerical simulations, it is demonstrated in a straightforward way that nonequilibrium disturbance (e.g. force, displacement, energy, and ...

An assessment of the effects of microstructure on room temperature fatigue crack initiation and short crack propagation in a Ni-base superalloy is presented. The assessment was carried out on microstructural variants of U720Li, including as-received U720Li, U720Li-LG (large grain variant) and U720Li-LP (large intragranular coherent γ′ variant). Fatigue tests were carried out at room temperature...

Methods Nine AIS patients undergoing casting for new braces participated in this pilot study (2 males, 7 females, aged 11-16, Cobb angles 16-44 degrees). An ultrasound scan was used to measure the patient’s (baseline) Cobb angle. The orthotist then used a custom standing Providence system to apply corrective pressures simulating a brace. A second ultrasound scan measured the new (corrected) Cob...