Study On Inverse Problems In Structures Dynamics And Its Application On Structural Damage Identification

Based on the Inverse Problems in Dynamics, this thesis discusses the damage identification procedure of structures.It is well known that, determining the damage parameters from modal parameter shifts belongs to the group of inverse problems of dynamics. In this thesis, the origin, definition, and dependence of the solution-uniqueness of the inverse problem and ill-conditioning are discussed first. From a theoretical standpoint linger, inverse problem is solvable in straightforward way. However, it requires significant computational efforts and usually results in non-convergence in practice. Alternatively, the genetic algorithms (GA) approach is adopted. Some numerical examples are presented after that.As for Modal Analysis and its application in Structural Damage Identification (SDI) are concerned, system's behavior is assumed to be linear, damage is represented by a more or less concentrated decrease in stiffness. Studies of the sensitiveness of the damage-indicators showed that the success of damage identification procedures depends much on the type of indicator employed for diagnostics. Finally, a generalization of the procedure based on floating-point-coding genetic algorithms associated with finite-element models, which makes possible the tackling possible complex structural cases, is developed and illustrated. Numerical examples are presented in succession and prove the proposed method to be robust and effective.