Numerical Simulation and Experimental Validation of Gap Supported Tube Subjected to Fluid-Elastic Coupling Forces for Hybrid Characterization Tests

Abstract

Steam Generator (SG) tubes are subjected to fluid-elastic coupling forces and impacts against support plates & anti-vibration bars. Understanding their vibrations is crucial not only at the design stage, but also to optimize the SG maintenance policy and to lengthen the SG service life. The aim of our research is to provide a better understanding of the conjugate stabilizing effects of impacts and coupling with fluid-elastic forces. Since fluid-elastic forces are difficult to simulate and expensive to reproduce experimentally, the fluid coupling forces of our numerical model are represented using velocity dependent damping and stiffness matrices, both for the fluid and the tube. Their effect is experimentally reproduced having recourse to active vibration control in the frame of specifically designed “hybrid” experimental tests. In this paper, we present a method for modeling tube vibrations in order to estimate the conjugate effects of the coupling between the fluid elastic forces and impacts. This strategy lowers the costs and avoids the difficulties associated to the case of fluid in the experiments. Our numerical model will be implemented in the active control loop in the next step of the study.