Approximate analysis of necklace coalescence

Two recent models of void coalescence in columns are revisited to provide simpler, approximate expressions for the effective yield surface. Unlike the exact criteria, these are not upper-bound preserving but provide more flexibility in numerical implementation of the models. Both models correspond to limit analysis on the same geometry, namely a cylindrical void of finite height embedded in a cylindrical cell. One model employs a continuous velocity field, the other a discontinuous, yet kinematically admissible velocity field. The approximations are assessed by direct comparison to the exact criteria for several sets of the internal parameters.

Automated summary

Two recent models of void coalescence in columns are reviewed to provide simpler approximations for the effective yield surface. These approximations, unlike the exact criteria, do not preserve upper bounds but offer more flexibility in numerical implementation. Both models involve limit analysis on a cylindrical void embedded in a cylindrical cell. The accuracy of the approximations is evaluated by comparing them directly to the exact criteria for different sets of internal parameters.