Speaker
Jacek Jackiewicz
Description
Material instability is often associated with the loss of ellipticity for the constitutive equations of the considered material. Determining when ellipticity is lost using the acoustic tensor is a bit complicated. For each load increment value of the updated Lagrangian formulation, the algorithm must assess the tangent modulus tensor at each point in the material. Accordingly, the Routh–Hurwitz stability criterion evaluates the loss of material stability. The Routh–Hurwitz criterion application requires transforming the finite element equilibrium equations to the state-space formulations for each load increment. The algorithm then changes the resulting discrete differences equation matrices into their continuous system form.
