Performance of low-order triangular elements during plastic flow
An important characteristic of many soil models is a volume change during plastic flow. In computations, this plastic volume change is expressed via a kinematic constraint on the possible deformations. Due to this constraint the plane-strain three-noded triangular element exhibits locking when plastic deformations occur, under dilatant, contractant and isochoric conditions. It is demonstrated that using the method of enhanced assumed strains by Simol this locking cannot be remedied. Far six-noded wedges and four-noded and five-noded pyramids the same conclusion is obtained.
triangular element plastic flow