Design and Development of a Complex Shear Modulus Measurement Setup for Viscoelastic Materials

Details of the design and development study of a complex shear modulus measurement setup for viscoelastic materials have been presented in this paper. The new setup is specifically designed for measuring the complex shear modulus of pressure sensitive adhesives. The setup consists of a rigid block that is connected to a rigid fixture through two identical shear specimens of the viscoelastic material to be tested. The rigid block and the shear specimens resemble a single degree of freedom system. Once the frequency response function of the rigid block is measured, the frequency dependent material properties of the viscoelastic material can be calculated in a frequency range of 20 to 200 Hz. The setup also has a forced liquid convection heating/cooling system that enables testing in a temperature range of 5° F to 200° F. Test results for a sample viscoelastic material have also been presented in this paper. Basic principals of this testing method can be found in various sources, yet very few of them provide detailed information for practical implementation. Also, unlike the widely-known vibrating beam technique, no detailed standards exist on the subject. The main objective of this paper is to be an aid for future implementations of the testing approach through summarizing this recent effort for the design, analysis and construction of a sample test setup.