DYNAMIC RESPONSE RESEARCH OF U SHAPED PIPE WITH VISCOELASTIC DAMPING LAYER

The frequency dependency property of viscoelastic material leads to the dynamic analysis of compound structures which are complex and costly. Furthermore, using commercial finite element software, it is difficult to carry out the dynamic response analysis with this characteristic. Based on finite element iterative and modal strain energy (MSE) method, a mode superposition algorithm was proposed to solve the dynamic response of viscoelastic damping structure in this paper. Through iterative and MSE method, the modal frequency and loss factor for each mode can be obtained. Before calculating the next order modal frequency, the modal mode and corresponding load are extracted and the response of node was calculated at first in this algorithm. As a consequence, the node displacement response can be solved by summarizing the response results of each independent mode in the required frequency range. Numerical calculation of U shaped pipe with viscoelastic damping layer illustrates that the method is simple and practical. Moreover, the simulations with this method agree quite well with the experimental derived results. In the meantime, the damping layer parameters study shows that the position of the damping layer has an obvious effect of reducing the vibration response of U shaped pipe, but the width of the damping layer has little influence. The procedure proposed in this paper can be extended to analyze other more complex structures with viscoelastic material.