Kaishin Liu

A numerical method for axisymmetric wave propagation problem of anisotropic solids

A numerical algorithm based on the method of characteristics is presented for calculating axisymmetric wave propagation problems of anisotropic solids. The algorithm is applied to study the dynamic behaviour of a transversely isotropic tube due to impact loading. The stability of the present algorithm is investigated. The limitation in the treatment of boundaries and the advantages of present method are discussed.

A numerical solution of transient torsional wave propagation in a transversely isotropic cylinder

SummaryA numerical technique is proposed to obtain the solution for the transient torsional wave propagation in a transversely isotropic cylinder when a torque is suddenly applied to its end surface. The dynamic behavior in the vicinity of the impact end of the transversely isotropic cylinder is studied. The stability and convergence of the present numerical technique and the validity of the numerical solution are examined.

Reflection characteristics of torsional waves in transversely isotropic stepped bars

Abstract By means of the method of numerical integration along bicharacteristics, propagation of transient torsional waves in transversely isotropic stepped bars are analysed under the incident torsional stress pulse varies proportionally with the distance from the stepped bar axis. The numerical results for a special transversely isotropic stepped bar are compared with the available exact solutions. The influence of the size and material property of the stepped bar on its reflection characteristic is presented.

Numerical analysis for dynamic stress concentration in a rectangular block due to impact

This paper presents a numerical analysis for three-dimensional stress waves in an elastic rectangular block subjected to compression pulses at its end surface. The numerical technique is based on the method of finite differences along bi-characteristics. By obtaining the numerical results for various loading conditions and Poissons ratios of the block, the effect on the tensile stress concentration in the block is demonstrated clearly. It is shown that the generation of the peculiar fracture patterns for a brittle rectangular block, which were presented by Kolsky and Shearman can be explained well by the distribution of maximum tensile stress arising in the block.

Dynamic Behavior of Elastic/Viscoplastic Stepped Bar Due to Torsional Impact.

Two-dimensional elastic/viscoplastic stress waves in a semi-infinite stepped bar are analyzed numerically, when torsional impacts are applied to the end face of the stepped bar. For the numerical analysis, a finite difference method along the bicharacteristic is employed. By examining the distributions of maximum tensile stress arising in the vicinity of the junction of the stepped bar, influences of the stepped bar shape and loading condition on stress concentration are investigated. It is also found that the maximum tensile stress is at the corner of the stepped bar for every numerical condition.