Full-field measurement techniques such as the scanning laser Doppler vibrometer (LDV) and the electronic speckle pattern interferometry systems can provide a dense and accurate vibration measurement on structural op...Full-field measurement techniques such as the scanning laser Doppler vibrometer (LDV) and the electronic speckle pattern interferometry systems can provide a dense and accurate vibration measurement on structural operating deflection shape (ODS) on a relatively short period of time.The possibility of structural damage detection and localization using the ODS looks likely more attractive than when using traditional measurement techniques which address only a small number of discrete points.This paper discusses the decomposition method of the structural ODSs in the time history using principal component analysis to provide a novel approach to the structural health monitoring and damage detection.The damage indicator is proposed through comparison of structural singular vectors of the ODS variation matrixes between the healthy and damaged stages.A plate piece with a fix-free configuration is used as an example to demonstrate the effectiveness of the damage detection and localization using the proposed method.The simulation results show that:(1) the dominated principal components and the corresponding singular vectors obtained from the decomposition of the structural ODSs maintain most of all vibration information of the plate,especially in the case of harmonic force excitations that the 1st principal component and its vectors mostly dominated in the system;(2) the damage indicator can apparently flag out the damage localization in the case of the different sinusoidal excitation frequencies that may not be close to any of structural natural frequencies.The successful simulation indicates that the proposed method for structural damage detection is novel and robust.It also indicates the potentially practical applications in industries.展开更多
With the aid of non-contact measurements of vibrating surfaces through laser scanning,operating deflection shapes(ODSs)with high spatial resolutions can be used to graphically characterize damage in plane structures.A...With the aid of non-contact measurements of vibrating surfaces through laser scanning,operating deflection shapes(ODSs)with high spatial resolutions can be used to graphically characterize damage in plane structures.Although numerous damage identification approaches relying on laser-measured ODSs have been developed for plate-type structures,they cannot be directly applied to circular cylinders due to the gap between equations of motions of plates and circular cylinders.To fill this gap,a novel approach is proposed in this study for damage identification of circular cylinders.Damage-induced discontinuities of the derivatives of ODSs can be used to gra-phically manifest the occurrence of the damage,and characterize the location and size of the damage.The approach is experimentally validated on a specimen of the circular cylinder component,whose out-of-plane ODSs in an inspection region are acquired through laser scanning using a scanning laser vibrometer.The results suggest that the occurrence,location,and size of the internal damage of the circular cylinder can be identified.展开更多
基金supported by Jiangsu Provincial Natural Science Foundation of China (Grant No. BK2008383)Scientific Research Foundation for the Returned Overseas Chinese Scholars,Ministry of Education of China (Grant No. M0903-021)+1 种基金Nanjing University of Aeronautics and Astronautics Grant for the Talents,China (Grant No.KT50838-021)Jiangsu Provincial Research Foundation for Talented Scholars in Six Fields of China (Grant No. P0951-021)
文摘Full-field measurement techniques such as the scanning laser Doppler vibrometer (LDV) and the electronic speckle pattern interferometry systems can provide a dense and accurate vibration measurement on structural operating deflection shape (ODS) on a relatively short period of time.The possibility of structural damage detection and localization using the ODS looks likely more attractive than when using traditional measurement techniques which address only a small number of discrete points.This paper discusses the decomposition method of the structural ODSs in the time history using principal component analysis to provide a novel approach to the structural health monitoring and damage detection.The damage indicator is proposed through comparison of structural singular vectors of the ODS variation matrixes between the healthy and damaged stages.A plate piece with a fix-free configuration is used as an example to demonstrate the effectiveness of the damage detection and localization using the proposed method.The simulation results show that:(1) the dominated principal components and the corresponding singular vectors obtained from the decomposition of the structural ODSs maintain most of all vibration information of the plate,especially in the case of harmonic force excitations that the 1st principal component and its vectors mostly dominated in the system;(2) the damage indicator can apparently flag out the damage localization in the case of the different sinusoidal excitation frequencies that may not be close to any of structural natural frequencies.The successful simulation indicates that the proposed method for structural damage detection is novel and robust.It also indicates the potentially practical applications in industries.
基金The authors are grateful for the supports from the Changzhou Policy Guidance Plan-International Science and Technology Cooperation(No.CZ20200003)the Anhui International Joint Research Center of Data Diagnosis and Smart Maintenance on Bridge Structures(No.2021AHGHYB01)+1 种基金the Nantong Science and Technology Opening Cooperation Project in 2021(No.BW2021001)the Key R&D Project of Anhui Science and Technology Department(202004b11020026).
文摘With the aid of non-contact measurements of vibrating surfaces through laser scanning,operating deflection shapes(ODSs)with high spatial resolutions can be used to graphically characterize damage in plane structures.Although numerous damage identification approaches relying on laser-measured ODSs have been developed for plate-type structures,they cannot be directly applied to circular cylinders due to the gap between equations of motions of plates and circular cylinders.To fill this gap,a novel approach is proposed in this study for damage identification of circular cylinders.Damage-induced discontinuities of the derivatives of ODSs can be used to gra-phically manifest the occurrence of the damage,and characterize the location and size of the damage.The approach is experimentally validated on a specimen of the circular cylinder component,whose out-of-plane ODSs in an inspection region are acquired through laser scanning using a scanning laser vibrometer.The results suggest that the occurrence,location,and size of the internal damage of the circular cylinder can be identified.