UNSTRUCTURED MULTIGRID METHOD FOR SHELLS

An accelerated multigrid method, which exploits shell element formulation to speed up the iterative process, is developed for inherently poor conditioned thin domain problems on unstructured grids. Its building blocks are: (i) intergrid transfer operators based on the shell element shape functions, (ii) heavy smoothing procedures in the form of Modified Incomplete Cholesky factorization, and (iii) various two- and threeparameter acceleration schemes. Both the flat shell triangular element and the assumed strain degenerated solid shell element are considered. Numerical results show a remarkable robustness for a wide spectrum of span/thickness ratios encountered in practical applications