FINITE-ELEMENT ANALYSIS OF 2-PHASE INSTABILITY FOR SATURATED POROUS HYPOELASTIC SOLIDS UNDER PLANE-STRAIN LOADINGS

Investigates the effects of two-phase instability on finite element (F E) solutions for porous hypoelastic solids saturated with an instersti tial fluid. Demonstrates that two-phase instability creates definite p roblems to the FE computations of coupled solid-fluid systems. The eig envectors oi the tangential finite element matrices which are responsi ble for problems are not artificial, but are the bifurcating modes of physical solutions. The investigation, although limited to the plane s train undrained compression of hypoelastic models, is relevant to the investigation of the two-phase instability of other materials and boun dary value problems, and may lead towards an explanation for numerical problems in soil liquefaction analysis.