Dynamic Response to Normal Stresses in a Transversely Isotropic Material Containing an External Circular Crack

1992 ◽  
Vol 114 (2) ◽  
pp. 208-212 ◽  
Author(s):  
Y. M. Tsai
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Isotropic Material ◽  
Dynamic Stress ◽  
Dynamic Stress Intensity Factor ◽  
Circular Crack ◽  
Transversely Isotropic ◽  
Transversely Isotropic Material ◽  
External Circular Crack

The dynamic response of an external circular crack to a harmonic longitudinal wave in a transversely isotropic material is investigated using the techniques of Hankel transform. The wave impinges normally onto the crack surfaces. The inversion integral is evaluated and simplified through a complete contour integration. An exact expression for the dynamic stress intensity factor is obtained in terms of the wave frequency and the anisotropic material constants. The maximum value of the normalized dynamic stress-intensity factor is shown to occur at different wave frequencies for different sample composite and metallic materials. The dynamic effect on the crack surface displacement is also shown to be a function of the wave frequency and the material anisotropy.

Torsional Vibration of an External Circular Crack in a Transversely Isotropic Composite

2002 ◽  
Author(s):  
Y. M. Tsai
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Dynamic Stress ◽  
Dynamic Stress Intensity Factor ◽  
Circular Crack ◽  
Transversely Isotropic ◽  
Dynamic Crack ◽  
Isotropic Composite ◽  
External Circular Crack

The forced torsional vibratory motion of an external circular crack in a transversely isotropic composite is investigated by using the method of Hankel transforms. A pair of vibratory torques of equal amplitude is applied at infinity. The infinite integral involved is evaluated through a contour integration to be discontinuous in nature. An exact expression for the dynamic stress intensity factor is obtained in terms of the frequency factor and the anisotropic material constants. The maximum value of the normalized dynamic stress-intensity factor is shown to occur at different frequency factors for the sample fiber-reinforced and metal matrix composites. The distortion of the dynamic crack surface displacement from the associated static displacement depends also on the forcing frequency and the material anisotropy.

Forced Vibrations of a Transversely Isotropic Composite Containing an External Circular Crack

2001 ◽  
Author(s):  
Y. M. Tsai
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Dynamic Stress ◽  
Crack Surface ◽  
Dynamic Stress Intensity Factor ◽  
Circular Crack ◽  
Transversely Isotropic ◽  
Force Frequency ◽  
Isotropic Composite ◽  
External Circular Crack

Abstract The problem of a transversely isotropic composite containing an external circular crack is investigated using the method of Hankel transforms. A pair of tensile vibratory forces of equal amplitude are applied normal to the crack surface at infinity. A complete contour integration is employed to simplify the expressions of the results. An exact expression of the dynamic stress-intensity factor is obtained as a function of the force frequency and the anisotropic material constants. The normalized dynamic stress-intensity factor is shown to have different maximum values at different force frequencies for the sample fiber-reinforced and metal matrix composites. The deviation of the dynamic crack surface displacement from the associated static displacement is also shown to be dependent on the force frequency and the anisotropy of the material.

The Dynamic Stress Intensity Factor Due to Arbitrary Screw Dislocation Motion

1983 ◽  
Vol 50 (2) ◽  
pp. 383-389 ◽  
Author(s):  
L. M. Brock
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Plane Wave ◽  
Screw Dislocation ◽  
Dynamic Stress ◽  
Critical Level ◽  
Dynamic Stress Intensity Factor ◽  
Dislocation Motion ◽  
Crack Edge

The dynamic stress intensity factor for a stationary semi-infinite crack due to the motion of a screw dislocation is obtained analytically. The dislocation position, orientation, and speed are largely arbitrary. However, a dislocation traveling toward the crack surface is assumed to arrest upon arrival. It is found that discontinuities in speed and a nonsmooth path may cause discontinuities in the intensity factor and that dislocation arrest at any point causes the intensity factor to instantaneously assume a static value. Morever, explicit dependence on speed and orientation vanish when the dislocation moves directly toward or away from the crack edge. The results are applied to antiplane shear wave diffraction at the crack edge. For an incident step-stress plane wave, a stationary dislocation near the crack tip can either accelerate or delay attainment of a critical level of stress intensity, depending on the relative orientation of the crack, the dislocation, and the plane wave. However, if the incident wave also triggers dislocation motion, then the delaying effect is diminished and the acceleration is accentuated.

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