Vibration Based Techniques for Young's Modulus Determination and Permenant Deformation Assesment

Abstract: This thesis work is devoted to low frequency vibration based method, with remote excitation and laser detection for nondestructive testing and characterization of sheet materials. By this method dynamic properties of different materials can be estimated from the measurement of the resonance frequency in flexural mode. Low Density Polyethylene (LDPE), Ethyl Acid Acrylic (EAA), Aluminium foil (Al) and Paperboard (PPR) are investigated in this work. It is observed that the method allows detection of permanent deformation in sheet materials loaded in tension, as well as determination of Young’s modulus with some exceptions. This study also confirms the use of the presented method for health monitoring of materials having no bending stiffness, developed in a previous work.