Effects of the legacy pipe ends on the behaviour of pipe-in-pipe repair systems under internal pressure
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Engineering topics
Publications and source records attributed to Karunasena, W..
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Dispersion of guided waves in a cross-ply laminated plate has been studied here using a stiffness method and an exact method. It is shown that the number of laminae strongly influences the dispersion behavior. Further, it is found that when the number of laminae is sufficiently large, then the dispersion behavior can be predicted by treating the plate as homogeneous with six stiffness constants obtained by using an effective modulus method.
Guided wave propagation in a periodically laminated plate is considered when each lamina is transversely isotropic with its symmetry axis lying in the plane of the graphite-epoxy plate. The dispersion behavior of propagation modes influences the dynamic response and can be used to ultrasonically characterize the mechanical properties of the laminated plate. It is assumed that fibers are oriented at 90 deg to one another in adjacent layers and all the laminae are of equal thickness. Results obtained are in good agreement with exact solutions of previous studies.
Characteristics of wave propagation in an undamaged composite medium are influenced by many factors, the most important of which are: microstructure, constituent properties, interfaces, residual stress fields, and ply lay-ups. Measurements of wave velocities, attenuation, and dispersion provide a powerful tool for nondestructive evaluation of these properties. Recent developments are reviewed for modeling ultrasonic wave propagation in fiber and particle-reinforced composite media. Additionally, some modeling studies are reviewed for the effects of interfaces and layering on attenuation and dispersion. These studies indicate possible ways of characterizing material properties by ultrasonic means.