30 8 JOURNAL OF VIBRATION AND SHOCK Vol. 30 No. 8 2011 1 2 1 2 2 1. 100044 2. 361005 TU317. 1 A Structural damage detection method based on correlation function analysis of vibration measurement data LEI Jia-yan 1 2 YAO Qian-feng 1 LEI Ying 2 LIU Chao 2 1. School of Civil Engineering Beijing Jiaotong University Beiiing 100044 China 2. Department of Civil Engineering Xiamen University Xiamen Fujian 361005 China Abstract A structural damage identification technique based on correlation function analysis of vibration measurement data was proposed. An 8-storey steel shear building model was chosen as example in the case verification. The results demonstrate that accident magnitude change of correlation function can be used to locate the damage by comparing the shape changes between damaged and undamaged samples. The value of CVAC is effective to determinate whether the damage has happened or not and it can be used as a reference method even for on-line structural health monitoring. The parameter K defined to detect damage severity corresponds to the theoretical damage level in different cases. Key words damage identification correlation function stochastic vibration vibration test 1 2 5 6 CorV CVAC CorV 7 8 863 2007AA04Z420 2010-02 - 22 2010-06 - 28 1978 1
222 4 ~ 9 R R K 1. 2 CVAC CVAC 6 1 n-1 R i R * i 2 1. 1 CVAC = 7 n-1 R i 2 n-1 R * i 2 R i R * i 3 CVAC 0 1 CVAC = 1 CVAC = 0 6 2 x 1 x 2 τ = E x 1 t x 2 t + τ = 7 8 - x 1 x 2 p x 1 x 2 dx 1 dx 2 1 CVAC - 1 τ = lim T T T x 1 t x 2 t + τ dt 2 0 6 R R 1 Δt R 1 = R * /max R 8 T N = T Δt + 1 i i + 1 R * 1 k = 1 N-k x N 1 i x 2 i + k K K = abs r * i i +1 - r i i +1 /r i i +1 9 k = 0 1 2 N 3 r i i + 1 r * i i + 1 K r l l +1 = xl x l+1 τ = xl x l+1 k 4 0 1 K n 1. 3 R = r 1 2 r 2 3 r n-1 n 5 3 R = r k 1 r k 2 r k n 6 5 6 k r 0 1
8 223 1. 4 5 i i + 1 x i x i + 1 x z i x z i + 1 v i v i + 1 2 σ i σ i + 1 τ = E x i t x i +1 t + τ = E x z i t + v i t x z i +1 t + τ + v i +1 t + τ = E x z i t x z i +1 t + τ + x z i t v i +1 t + τ + v i t x z i +1 t + τ + v i t v i +1 t + τ = E x z i t x z i +1 t + τ + E x z i t v i +1 t + τ + E v i t x z i +1 t + τ + E v i t v i +1 t + τ = E x z i t x z i +1 t + τ + E v i t v i +1 t + τ = E x z i t x z i +1 t + τ + E v i t E v i +1 t + τ = E x z i t x z i +1 t + τ Fig. 2 Comparison of signals between tested and preprocessed 2. 2 2 1 2. 1 CVAC 1 1 350 mm 250 mm 200 mm CVAC 1 CVAC CVAC 1 RIGOL DG - 1022 PCB 100 Hz 50% 4 25% 2 3 R 4 a 4 b 25% 5 1 2 1 25% Fig. 1 Test model 3
224 1 CVAC Tab. 1 CVAC values of structure 1 2 1 3 1 4 1 5 2 3 2 4 2 5 3 5 4 5 CVAC 0. 999 3 0. 999 1 0. 999 5 0. 999 8 0. 999 9 0. 999 9 0. 999 8 0. 999 8 0. 999 9 1CVAC 0. 999 8 0. 998 7 0. 999 8 0. 999 6 0. 998 8 0. 999 9 0. 999 3 0. 999 3 0. 999 5 2CVAC 0. 999 9 0. 999 7 0. 999 8 0. 999 8 0. 999 8 0. 999 7 0. 999 9 0. 999 5 0. 999 7 3CVAC 0. 998 2 0. 998 7 0. 998 7 0. 997 6 0. 999 8 0. 999 8 0. 999 9 0. 999 7 0. 999 7 2 K Tab. 2 K values of structure with different damages K1 1 /% K2 2 /% K3 3 /% K4 4 /% K5 5 /% K /% 1 28. 8 3. 8 23. 7 2. 3 22. 6 2. 4 24. 8 0. 2 28. 5 3. 5 25. 68 0. 68 2 51. 4 1. 4 51. 2 1. 2 48. 1 1. 9 49. 0 1. 0 49. 8 0. 2 49. 9 0. 10 3 1 30. 9 5. 9 30. 0 5. 0 29. 1 4. 1 27. 6 2. 6 29. 9 4. 9 29. 5 4. 5 3 2 24. 2 0. 8 25. 2 0. 2 20. 9 4. 1 23. 2 1. 8 20. 0 5. 0 22. 7 2. 3 3 1 3 2 2. 3 2 K K K1 ~ K5 1 ~ 5 1% 5. 9% 5% 3 CVAC K 236
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