Structural Damage Identification By Dynamic Stiffness Matrix Method

Because of various factors, engineering structures will be damaged inevitably, even lead to serious consequence, which will affect safety and usability of structures. Therefore, it is necessary to monitor the health of engineering structures. The applications of structural response to vibrations and the parameter for the systematic dynamic characteristics to the diagnosis of structural damage has been in vogue both home and abroad. By focusing on bar element structural damage identification, this thesis proposes a new method of structural damage identification-dynamic stiffness matrix.Based on the finite element analysis theory, the author proposes a new method of structural damage identification-dynamic stiffness matrix, and then derives its dynamic stiffness matrix. No matter how complex the system is, structures can be analyzed by displacement method which according to the same process with the static direct stiffness method, superimposing of the stiffness which contribute of beam elements to form stiffness matrix of the whole structure, and then obtains the displacement by solved the whole system stiffness matrix of a given load. New features which the dynamic stiffness coefficient have is only a function of frequency, analyzed the structure of the node displacements and element strain. Untold of the damage, assuming the measurable strain as the known data, the author then employs the Tikhonov Regulation Method and Genetic algorithm to identify the damage index of the structural node.Using the dynamic stiffness matrix method, the cantilever beams, simply supported beams and frames are then examined for damage, whose location, degree and the impact of the loaded position upon the damage identification are also to be analyzed with numerical examples.