Study On The Damage Identification Based On The Frequency Response Function Curvature

With the progress of the society and the development of science and technology, Size and complexity of modern engineering structures have very big margin improvement. Large civil engineering structures will have unavoidable damage accumulation during the using period, due to the effect of loads, earthquake, fatigue and corrosion, fires and other natural disasters or materials aging.The maintenance of the damage structure has brought a huge loss in terms ofeconomy, and failed to timely found the damage is affecting people’s life safety. This requests us find out damage detection methods timely which is quick and efficiently, and can accurately identify the structure damage and repair in time, to extend the life of the structure and ensure the safety of the structure.Several structural damage identification methods based on vibration parameters was introduced in this paper. Simply introduced from the theory and practical applications, also listed their respective advantages and disadvantages and the existing problems to be solved.A laboratory investigation was conducted on timber beam which inflictedwith different size and position of damage scenarios using modal test. From the test we can obtain the modal parameters and frequency response function. Using the frequency response function curvature ratio for damage identification, the test results and analysis show that this method can detect damage with higher degree of confidence. In structure dynamic test, the frequency response function is get from the active structural vibration under stationary state, with the dual-channel fast Fourier transform of the excitation and response. From this avoids the error of the modal extract and provide more information of structuraldamage. So this method is very convenient using in structural damage detection. Frequency response function curvature ratio can accurately reflect the damage location and degree, and have advantages in simple measurement and convenient calculation. In this paper, also build the finite element numerical model of the actual structure, which provides the modal data of the Nondestructive status Structure. Also provides basis for further research and verifying the rationality of design and modification specification. Experimental and numerical simulation analysis verified that frequency response function curvature method’s sensitivity of the damage to the timber beam, Can accurately identify the damage location and degrees. And the analysis of the choice of frequency range are discussed in this paper. There is important significance in wood structure health monitoring, early warning and timely maintenance aspect.