Experimental research on damage identification of fully free beams based on modal shapes: Fid-Bau Portal

Experimental research on damage identification of fully free beams based on modal shapes

Cheng, Haoyue / Guo, Jun / Zhang, Yin / Li, Wenzhuo

Abstract Ship damage identification is a new field of ship research, which is of great significance to damage control, life and property safety and strategic decision-making, but there is no effective method for ship damage identification. The structural system changes caused by ship damage are usually represented by the change of system mass, stiffness and energy dissipation characteristics, and then the change of structural dynamic characteristic parameters, which provides a theoretical basis for ship damage identification. In this paper, the ship is simplified as a beam model with fully free boundary conditions. Based on the dynamic characteristic parameter of the modal shape, the damage identification of the ship under six damage conditions is carried out through numerical simulation and experimental verification by using COMAC and the derived indexes of curvature mode and modal flexibility. The results show that the first four orders of curvature mode difference mean index and the curvature index of modal flexibility change rate can accurately locate the damage of hull beam structure; The damage degree of hull beam can be identified by the change of curvature mode difference index, but there are some errors in this method; The curvature index of modal flexibility change rate is positively correlated with the damage degree, which can reflect the damage degree of the structure. The research results of this paper can provide new methods and ideas for hull beam damage identification.