Читать книгу Finite Element Analysis - Barna Szabó - Страница 43

The goal of finite element computations is to estimate certain quantities of interest (QoIs) such as, for example, the maximum and minimum values of u or on . Since finite element solutions are approximations to an exact solution, it is not sufficient to report the value of a QoI computed from the finite element solution. It is also necessary to provide an estimate of the relative error in the QoI, or present evidence that the relative error in the QoI is not greater than an acceptable value.

In this section we will use the a priori estimates described in Section 1.5.2 to obtain a posteriori estimates of error in energy norm. It is possible to obtain very accurate estimates for a large class of problems which includes most problems of practical interest.