Construction and qualification of a micro-tensile testing machine for lower scale digital image correlation applied to Zirconium alloys

Abstract

The aim of this project is the construction, programming and operation of a thermo-mechanical testing machine for the study of the mechanical properties of nuclear fuel cladding material. The strain information is estimated using Digital Image Correlation techniques on pictures taken with a digital camera during the thermo-mechanical test. This prototype will provide better understanding of the local effects of thermo-mechanical loads of hydrogenated Zircaloy cladding. To understand the relevance of this topic, comprehension of how and why the hydrogen uptake process takes place inside Zircaloy claddings is necessary. A short explanation of his process as well as the relation between hydrogen content and the mechanical properties of Zircaloy is the introduction to this work. The next part of this project is dedicated to the setup of the structure and the installation of the five different electric systems of the prototype: force, heating, vacuum, control and optical system. An explanation of the LabView code designed to control the machine is included in this part. After this explanation, qualification of the optical system and Digital Image Correlation code is presented later, with thermal essay results. Hydrogenated Zircaloy sample preparation and experimental set-up is detailed for future experiments. The qualification of the machine finishes with the estimation of the linear thermal coefficient of the machine using DIC.