Mechanical Properties of Crimped Mineral Wools: Identification from Digital Image Correlation

Abstract

Mineral wool is usually used for thermal and acoustic insulation with no need for mechanical performances. However there are some applications where this material must have a significant stiffness and strength to sustain mechanical loads. Crimping is performed to enhance the mechanical properties of mineral wool. As this process is governed by a lot of parameters one looks for ways to characterize the mechanical properties one-line. The aim of the present paper is to present an identification technique for the elastic properties of such a medium, based on texture analysis, digital image correlation, and a Finite Element based identification. Local anisotropic elastic behavior is identified through a combination of different tools based on image processing. First the local orientation map is determined from a reference image. Second, a series of images captured at different loading stages is analyzed with a digital image correlation code to estimate the local displacement field. Last, an inverse problem procedure is applied to evaluate the four elastic moduli of the material. The first experimental step is to perform mechanical tests on this type of material, and then the measurement and identification steps. A hexapod is used to perform a biaxial experiment (compression and shear).