This paper on "Some Experiences with Two Error Estimators within a Commercial Finite Element Code" was presented at the 3rd International Conference on Quality Assurance and Standards in Finite Element Analysis - 10-12 September 1991, Stratford-upon-Avon, England.

Abstract

Error estimates based on the Zienkiewicz-Zhu energy error norm were made available in the ANSYS® program for 2-D and 3-D stress solids in early 1989. Since then, an analogous error estimator has been made available for shell elements. A new heuristic estimator of stress uncertainty in finite element solutions was also included in the program at that time. This paper briefly reviews the error in energy norm as it applies to finite element analysis with shell elements, and introduces this new heuristic method for estimating finite element discretization error based on nodal component stress deviation.
The use of these error estimators and their acceptance by the user community is discussed. Several examples demonstrating the behavior and utility of these error estimators on solutions 10 NAFEMS benchmarks and other problems are presented.