Structural Damage Identification Method Based On Modal Parameters Of The Project

Modern project structures are proceeding at the direction of maximization, complication, automation and continuousness. The complicated environments of service threat functional safety of the structure. To guarantee the safety and avoid disaster, the scholars, engineers and technicians are paying attention to the research of identification for the damage of structure real-timely, on-line and accurately.It elaborates the contents and requirements of the technique means of fault diagnosis and damage identification for structure, and the present research and application of damage identification for structure with vibration diagnosis technique; Based on the modal parameters, it discusses the theory and technique of the damage identification for structure with the flexibility difference method and curvature modal method, then present the idea of damage identification for structure with flexibility difference curvature method. The application of the three damage identification techniques above for simple supported beams and cantilever beams confirm that vague or wrong location will occur in the damage location method based on flexibility difference, and the curvature modal method need not rely on the structural parameter before the damage, but has the hidden trouble of vague location for small damage. It studies and puts forward the flexibility difference curvature method, and many simulated damage examples show that the method has notable advantages such as high damage identification sensitivity, strong reliability, and visualization and simplicity in amount and graph analysis.The use of the batten interpolation for modal parameter in the curvature modal and flexibility difference curvature method can solve the contradiction between decreasing measure points and the guarantee of identification precision ; The identification program has also been developed in Matlab: as long as the former 3 step vibration shape and frequency are input, the value and the graphic representation of damage identification will be obtained by flexibility difference curvature method.