L. G. Zhou¹, L. M. Hsiung², Hanchen Huang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.6, No.3, pp. 245-252, 2004, DOI:10.3970/cmes.2004.006.245

Abstract Using molecular dynamics simulations, we study the deformation of polysynthetically twinned (PST) TiAl at room temperature. The simulation cell is pre-strained and thermodynamically relaxed to zero stress, so that no dislocations pre-exist in γ−α₂ interfaces. A uniaxial compression is then applied along one 1/6<112] direction. Our results show that interfacial dislocation pairs nucleate at the γ−α₂ interface under the compression. The glide and agglomeration of these dislocations lead to the nucleation of deformation twins from the interface. Based on our studies, twins may nucleate without pre-existing interfacial dislocations. Further we have monitored the propagation of the More >

G. Cocchetti², G. Maier², X. P. Shen³

CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.3, pp. 279-298, 2002, DOI:10.3970/cmes.2002.003.279

Abstract Interface models mean here relationships between displacement jumps and tractions across a locus of displacement discontinuities. Frictional contact and quasi-brittle fracture interpreted by cohesive crack models are typical mechanical situations concerned by the present unifying approach. Plastic-softening multidissipative interface models are studied in piecewise linear formats, i.e. assuming linearity for yield functions, plastic potentials and relationships between static and kinematic internal variables. The properties and the pros and cons of such simplified models in a variety of formulations (fully non-holonomic in rates, holonomic and in finite steps), all mathematically described as linear complementarity problems, are More >