Papers by Author: Yong Jun Li

Abstract: A new method called Grey Relation Modal Flexibility Curvature Difference (GRMFCD)is proposed and applied to the numerical experiment and experimental research of a substructure. The results show the ability of GMFCD to locate the inflicted damage and qualitatively evaluate its severity for single and multiple scenarios, with only a few lower order modal parameters. The effectiveness and advantages of GMFCD as compared to the flexibility indicators, such as the change in flexibility, the curvature of the flexibility difference, are demonstrated.

Abstract: The frequencies and vibration modes of a launch platform are acquired through finite element simulation, and their actual values are obtained through modal test. On this basis, constructing objective function for the structure modal parameter relative residual error to be minimum, can transform model updating problem into optimization problem. Then the trust region algorithm is adopted to solve this optimization problem. This algorithm bears better robustness and computing efficiency. Through model updating, the frequency and vibration mode errors are reduced, supplying a basis for further simulation.