Improvements in the design and analysis of the segmented expanding mandrel test

Abstract

The segmented expanding mandrel test is modified and improved to yield more quantitative information on the local stress and strain concentrations in Zircaloy tubing samples. The experimental apparatus has undergone changes in segment design, end restraint fixture design and the method of sample heating. These changes result in localization of stress and strain concentrations to known locations in the tubing, the introduction of a small degree of biaxiality and a more uniform sample temperature, respectively. A chamfered specimen design has been introduced for the purpose of producing a near plane-strain condition. Finite-element analysis has been added to provide information on the magnitude of localized stresses and strains given the sample geometry, test procedure and measured diametral strains. The resulting test represents a significant increase in the quantitative information produced in the segmented expanding mandrel technique.