A NEW APPROACH TO DYNAMIC CONDENSATION FOR FEM

A new dynamic condensation model reduction (CMR) theory is implemented into a linear finite element environment, and applied to transient tw o-dimensional elasticity problems. This approach, which utilizes proje ction operators, avoids both the periodic media and global boundary la yer restrictions which limit popular methods of homogenization/smoothi ng. This method is a general purpose approach that is applicable to he terogeneous media and allows dynamic degree of freedom (d.o.f.) reduct ion in a straight- forward fashion without the introduction of additio nal approximations. The CMR algorithm is directly applicable to genera l second-order (in time) linear differential equations and has been co upled with both explicit and implicit FEM solvers in this work. The CM R method contains Guyan reduction as a special case. Numerical results and direct comparisons to Guyan reduction for two-dimensional wave pr opagation problems are made. In addition, the results indicate a relax ation of the Courant stability limit for explicit analysis, allowing l arger time steps in the reduced models. Copyright (C) 1996 Elsevier Sc ience Ltd