Torsional impact response of multiple cylindrical interface cracks between a functionally graded interlayer and homogeneous material
功能梯度夹层多个环形界面裂纹扭转冲击

In this paper the problem of multiple cylindrical interface cracks located between a functionallygraded material(FGM)interlayer and its external homogeneous cylinder subjected to torsional impact loading isinvestigated.The FGM interlayer is assumed simultaneously to bond two coaxial dissimilar homogeneous elasticcylinders,and the shear modulus and mass density of the FGM interlayer are assumed to vary continuouslybetween those of the two coaxial materials.The number of cylindrical interface cracks is arbitrary.Themixed boundary value problem is at first reduced to a singular integral equation with a Cauchy type kernel inthe Laplace domain by applying Laplace and Fourier integral transforms and introducing dislocation densityfunction.The singular integral equation is then solved numerically.The dynamic stress intensity factor(DSIF)is also obtained by a numerical Laplace inversion technique.The DSIF is found to rise rapidly to a peak,then oscillate and tend to the static value.The influences of geometric configuration of the cracks and relativemagnitudes of the adjoining material properties are examined.It is found among others that the DSIF can begreatly reduced by increasing the FGM gradient.