Implementation of essential boundary conditions in a meshless method

Accurate imposition of essential boundary conditions is a main drawback in the use of the element-free Galerkin (EFG) method. A way to solve the probl em, is to use a constrained variational principle with a penalty function. This new treatment for essential boundary conditions is simple and logical and works very well in all numerical examples for 2-D potential problems th at are presented here, considering an approximation close to an interpolati on. It is shown that the present constrained variational formulation togeth er with the EFG method and appropriated weighting function exhibit very hig h accuracy and stability, for regular and irregular grids of nodes. Copyrig ht (C) 2000 John Wiley & Sons, Ltd.