ABSTRACT
This chapter presents various types of a-posteriori error estimation techniques. It also presents the basic procedures of recovery based, residual based, goal oriented and hierarchical techniques. Several a-posteriori error estimation methods have been developed to indicate the distribution of discretization error. The goal of many finite element computations is to determine specific output data of the finite element approximation. In contrast to other methods of computing error where the current solution is compared with the exact solution, this method compares the current solution with the next refined solution. The norm calculated using wavelet coefficients will show a sudden jump in some areas which will indicate the need for mesh refinement in the zone. The approximation of exact strain improves as the number of elements and order of polynomial increases. This approximated exact strain is compared with the strain in the elements to find the elements with large error.
