Design and analysis of multiaxial creep tests

Abstract

Often in the presentation of material data, not all significant measurements are tabulated, nor are all normal and abnormal fluctuations reported. In this paper a procedure is described for presenting the complete data as obtained from tests of thin-walled tubular creep test specimens. Thereafter, a procedure for processing the data is presented. The processed data is based in part upon results of detailed inelastic finite element analyses performed to determine uniform and constant stress quantities and effective gauge lengths. Because little prior experience exists in the use of fully instrumented internally pressurised cylinder tests to generate multiaxial thermal creep curves, the automated data acquisition and data reduction scheme developed in this test program will be of value to others currently involved in setting up similar testing programs. The data handling system significantly reduces the repetitive work involved in the generation of the material creep data at elevated temperatures. Also, this effort provides a baseline for standardisation of the methods of data acquisition and data interpretation and for simplification of data transmittal among organisations.