Discussion Forum

Dear all:

I am studying a soft & thick cylindrical shell under inner and outer time-dependent pressure loadings. The Solid Mechanics model is 2D (annulus), with a cylindrical pore in the cross-section. Isotropic linear elastic material is assumed, with a Young's modulus of 50 kPa and Poisson's ratio of 0.499.

In my time-dependent study, I constantly experience the following problem:
Failed to find consistent initial values.
Last time step is not converged.
- Feature: Time-Dependent Solver 1 (sol 1/t1)

I looked into previous posts on the convergence problems, tried to refine the mesh, break down time intervals in the time-dependent analysis, but cannot solve this problem.

However, I found that if the Young's modulus is elevated to 500 kPa there is more convergence problem. I checked the evolution of mesh (for Y = 500 kPa) and find no severe distortion of the grid. I thus suspect significant distortion of the mesh may occur for Y = 50 kPa, but I do not know how to solve it.

With this brief summary of my problem, could anyone here help me with the following 2 questions?

(1) did any one encounter this kind of problems and have some experience to share?

(2) how could I 'debug' the model and figure out where this convergence problem is caused? are there any good references for the details (I checked COMSOL's pdf manuals but did not find anything closely related)?

Thank you.

Zhiping