CONCEPTION OF AN EXPERIMENTAL DEVICE FOR MEASURING THE INPLANE SHEAR MODULUS OF FILM MATERIALS

A freely oscillating torsional pendulum was designed and built for mea suring the in-plane shear modulus of film materials. To make the work easier for the experimenter, an online computer application was also d eveloped with the help of numeric tools (Fourier and Hilbert transform s) for data acquisition and processing, The experimental part was perf ormed on various materials. Experiments on a brass foil (isotropic mat erial) validated measurements achieved with this experimental device. Experiments on orthotropic materials (base papers with different basis weights) gave prominence to the good reproducibility of measurements and to the ability for using this torsional pendulum. For this kind of material (large basis weight base paper), the in-plane shear modulus seemed independent of the fiber orientation.