Loss of Convergence of Nonlinear Analysis
Loss of convergence of the solution of nonlinear analysis calls for certain modifications of the underlying computational model - the following steps can be adopted:
- Increase the stiffness of the structure
- Decrease the applied loads
- Split the soil excavation in more steps
- Improve material parameters of existing soils
- Change material model of soils in places of plasticity
- Add reinforcing members (beams, anchors)
- Add supports
- Change parameters settings affecting the iteration process (increase number of iterations).
Distribution of plastic strains may provide some explanation to why the analysis failed to converge. Note that the distribution of equivalent plastic strain locates the regions of probable evolution of critical failure surfaces.
Analysis failed to converge - plot of equivalent plastic strain