Damage Identification Based On Vibration Response Covariance Parameters And D-S Evidence Theory

At first,this paper introduces the structure damage identification in the field of the research background and research status at home and abroad,some common structural damage identification methods are reviewed in this paper,based on this,puts forward using response covariance parameters as indicators of damage,and respectively using strain response and the acceleration response to damage identification,the resulting two kinds of damage identification index,the first is a strain response covariance parameters(Co S),the second is covariance parameters of acceleration response on different frequency bands(Co I),by comparing the structural damage before and after the identification,the damage of the Co S or Co I without structure analysis model,It can be realized by analyzing the measured strain response and acceleration response directly.However,since the excitation position and noise will affect the accuracy of these two damage indicators,D-S evidence theory fusion technology is proposed to improve its accuracy and applicability(D-S evidence theory fusion technology has the advantage of no prior probability).Co S change quantity of different incentive location of damage probability vector data fusion on D-S evidence theory can improve the accuracy of the final damage vector,using a seven layer frame structure including single damage and damage and so on the many kinds of damage condition of numerical simulation,to institute the suitability and effectiveness of the proposed method,the results show that the method can determine damage occurrence and accurately identify the damage locations,finally use laboratory test of simply supported beam is verified based on strain effect of covariance parameters and D-S evidence theory of damage identification method is effective.Has good localized strain response,but it’s easier to measure acceleration response,the local weak in strain response,due to the neglected modes are more sensitive to the damage,so this article use covariance parameters of acceleration response on different frequency bands to damage identification,in order to improve the covariance parameters of high order modal contribution in the process of damage identification,and ultimately improve the accuracy of damage identification.So in this paper,and the acceleration response at different frequency bands of covariance parameters as indicators of damage,through the D-S evidence theory fusion technology of different incentive location and noise,the different frequency band of acceleration response covariance parameters(Co I)of damage probability vector fusion,also with seven layer frame structure for a variety of damage condition of numerical simulation,and seven layers framework of laboratory test data is analyzed to validate,the results show that the method is sensitive to damage and robust to noise,is effective method of damage identification,and without a structure analysis model,this method has good prospects for engineering applications.