Thermomechanical interaction effects in composite sandwich structures – initial experimental analysis and derivation of mechanical properties

Abstract

An experimental study of the effect of increasing temperature on the tensile modulus of PVC foam is presented. The focus is on obtaining reliable measurements of specimen deformation using optical techniques based on digital image correlation (DIC). A FE model that accounts for the 3D strain distribution in the specimen was used to inform the test specimen design. A new testing methodology and test rig design is devised and described in the paper. Firstly, tests are conducted at room temperature using DIC to obtain the strain on two opposite surfaces of the specimen simultaneously, to assess the effect of any specimen misalignment and devise a correction approach referred to as a ‘misalignment ratio’. In the elevated temperature test only one face was optically accessible through an optical window in a thermal chamber. Therefore the experiments are performed over a temperature range of 30°C to 90°C using only a single camera and the misalignment ratio applied. It is shown that the proposed methodology provides precise measurements and the thermal degradation of the tensile modulus can be obtained