A High Precision Axisymmetric Triangular Element Used in the Analysis of Hydraulic Turbine Components

Abstract

A structural analysis program (Axibody) using conforming triangular finite elements is developed and applied to the study of composite axi-symmetric structures. Two types of elements are used: a novel axi-symmetric ring element and a two-dimensional plain stress element of varying thickness. The displacements in both cases are represented by a complete third-degree polynomial. The derivation of the stiffness and the consistent equivalent load matrices of the elements are described as well as a brief note on the program. Several examples are treated and the results are compared with the theoretical solution. A direct comparison with the results of a strain gauge test performed on a large stay ring—spiral case assembly is also made. Excellent agreement is obtained in all cases.