A new error indicator based on stresses for adaptive meshing with Hermite boundary elements

This work presents a new error indicator for adaptive meshing with Hermite boundary elements. The error indicator proposed here directly measures, in an approximate fashion, the error in the numerical solution for the stresse s. The basic idea behind the error indicator is to compare, on an element b y element basis, a solution for the stresses obtained with Hermite elements with a second, "reduced" solution. This "reduced" solution is obtained app roximating the field variables inside each element using Lagrangian shape f unctions together with the nodal values for the displacements and tractions that were obtained from the analysis with Hermite elements. In this sense, it is assumed that the bigger the difference between the two solutions, th e bigger the error in the numerical solution for the stresses corresponding to the model with Hermite elements. Since in the scheme presented here bot h numerical solutions are obtained from the same analysis, the cost associa ted with the computation of the error indicator is minimal. Due to its simp licity and reliability, this new error indicator is very convenient to lead adaptive processes. Furthermore, it can also be used in models with multip le subregions. (C) 1999 Elsevier Science Ltd. All rights reserved.