Theoretical and experimental analysis of dynamic characteristics of elastomeric materials

In this study dynamic characteristics of an elastomer specimen is modelled analytically. As a result of the analytical study an expression for the complex stiffness of the specimen which is a function of geometry, displacement amplitude, and complex Young modulus of the specimen is obtained. Complex Young modulus of the specimen which is a variable of the complex stiffness is modelled for five different configuration which are Maxwell model with two parameters, Voigt model with two parameters, Maxwell model wtih three parameters, Voigt model with three parameters, and Voigt model with five parameters as a function of frequency. To verify the models a test procedure is presented. The test procedure is applied to two different configurations which are constituted by mounting the same specimen in different shapes. The first configuration is tested for 2,56 kN, 4,90 kN, and 10 kN preload conditions and the second configuration is tested for 0,5 kN, and 1,01 kN preload conditions. All these tests are repeated for for the frequencies 0,5 Hz, 1,0 Hz, 1,5 Hz, and 2,0 Hz. For the second configuration, the specimen is also tested for 1,01 kN preload with 2 mm stroke at the same frequencies and with 3, and 4 mm strokes at 0,5 Hz frequency. By using the experimental results, the parameters of models are estimated. The estimation of the parameter is done numerically by using ?fsolve? command of MATLAB software. The estimated models and experimental results are compared and and with tihs process, the effects of configuration and number of parameters on the sensitivity of the models are investigatedAccording to experimental results, K´ and K´´ values increases with the preload. However, these values decreases as the strain amplitude increases. According to the results of analytical study, Maxwell models are more sensitive than Voigt models which have the same numbers of parameters. However, the sensitivitiy of Voigt model is increased by increasing the number of parameters. As a result of analytical study, the hysteresis cycles of the viscoelastic models are obtained and compared with the experimental results. According to the results, it is seen that the models cannot simulate the nonlinear behavior of the specimen but for the higher preload conditions at which the nonlinear behavior of the specimen is not dominant the models give consistent hysteresis cycles with experimental results.Key Words : Elastomeric material, viscoelastic material, dynamic characteristic, storage stiffness, loss stiffness, Maxwell model, Voigt model