In this paper the problem of a finite element stress recovery is considered. First, a new global coordinate independent approximation of a continuous stress field is presented. It has been shown that the proposed, FEDSS (Finite Element Displacement type Stress Smoothing) method is computationally more efficient, at least compared with the classical stress averaging procedure. Second, there is a numerical evidence that, at least for four noded isoparametric elements, any stress recovey procedure is less accurate in strain energy than direct FEA (Finite Element Analysis). It has also been shown that, for bilinear isoparametric elements, the relative energy error norm with respect to the exact solution, computed by lxl Gaussian integration is smallest for the raw FEA, compared with any other stress recovery procedure and any type of the numerical quadrature. Hence, one can recommend (under)integration in the midpoint of an element, i.e. in the derivative (stress) superconvergent point, when error indicators of Z-Z (Zienkiewicz-Zhu) type are calculated.

purchase the full-text of this paper (price £20)

go to the previous paper
go to the next paper
return to the table of contents
return to the book description
purchase this book (price £85 +P&P)