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| Statistical damage detection based on frequencies of sensitivity-enhanced structures |
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| DOI：10.7511/jslx20086157 |
| KeyWord:damage detection,small damage,dynamic characteristics,feedback control,statistical analysis |
| CHENG Yuan-sheng1 WANG Zhen1 2 |
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| Abstract: |
| A statistical method using frequencies of structures under control is proposed for detecting small damages.In the study,feedback control based on independent modal space control is first used to assign the pole of the system under detection intentionally.Then the prescribed characteristic frequencies of the structure under control,which may be more sensitive to the damage,are obtained and further employed to constitute a sensitivity-enhanced damage indicator(SEDI).The principle of sensitivity-enhancing feedback control for stiffness damage detection of multi-degree-of-freedom systems is argued in theory.To tolerate measurement noise on modal frequencies,a hypothesis test involving t-test that utilizes the SEDI to constitute the statistical quantity is employed to estimate the existence of damage while a statistical pattern recognition method that uses the feature vectors consisting of SEDI is employed to locate damage.Based on perturbation theory the feature vectors are normalized in order to eliminate the effect of damage extent on damage localization.The proposed method is verified by examples including the damage detections of the IASC-ASCE benchmark structure with self-defining single damaged brace.Simulation results show that the proposed damage indicators are more sensitive to damage by using the frequencies of the structures under control and are capable of detecting and locating small damage of structures. |
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