Solution Method
The program FEM serves to analyze geotechnical problems characterized by a nonlinear response of the soil or rock body. A successful analysis of most of such problems calls for an iterative solution of a given boundary value problem. Applying the finite element method (FEM) then leads to an incremental form of the equilibrium conditions written as:
where: | ΚΤ | - | instantaneous stiffness matrix |
Δu | - | vector of nodal displacement increments | |
Δf | - | vector of out-of-balance force increments |
This equation can be solved only approximately using a suitable numerical method. The goal of the method is to arrive, during the process of iteration, at such a state of stress and strain that satisfies the condition Δf = 0. To that end, the program offers two basic methods:
Analysis settings - setting the solution method