Lin-Zhi Wu

Dynamic stress intensity factors around two parallel cracks in a functionally graded layer bonded to dissimilar half-planes subjected to anti-plane incident harmonic stress waves

The time-harmonic problem of determining the stress field around two parallel cracks in functionally graded materials (FGMs) is studied. The Fourier transform technique is used to reduce the boundary conditions to four simultaneous integral equations which are then solved by expanding the differences of crack surface displacements in a series. The unknown coefficients in the series are obtained by the Schmidt method. Numerical calculations are carried out for dynamic stress intensity factors (DSIF) in FGMs.

A Mechanical Model of 3D Braided Composites with Internal Transverse Crack

A laminated mechanical model has been developed that can predict the mechanical properties of 3D braided composites with internal transverse crack. By using the principle of minimum complementary energy, the stress components are obtained in closed-form expressions in terms of a perturbation function, which is governed by two fourth-order inhomogeneous ordinary differential equations. The effective Young’s modulus and Poisson’s ratio of 3D braided composites with internal crack are calculated using the homogenization theorem. To demonstrate the solution, some examples are analyzed. Good agreement is obtained between the presented results and the values predicted by the modified finite element method.