1 / 12

SHM: Damage Locating Vector

SHM: Damage Locating Vector. 7/9/2009 Shinae Jang. -4. 10. -5. 10. -6. 10. -7. 10. -8. 10. -9. 10. 0. 20. 40. 60. 80. 100. 120. 140. 160. 180. 200. 1. 0.8. 0.6. 0.4. 0.2. 0. 1. 2. 3. Three Stages of SHM. Impulse response. Data measurement/acquisition

mrinal
Télécharger la présentation

SHM: Damage Locating Vector

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. APSS-SHM lab SHM: Damage Locating Vector 7/9/2009 Shinae Jang

  2. -4 10 -5 10 -6 10 -7 10 -8 10 -9 10 0 20 40 60 80 100 120 140 160 180 200 1 0.8 0.6 0.4 0.2 0 1 2 3 Three Stages of SHM Impulse response • Data measurement/acquisition • Sensors and data acquisition equipment Transfer function 2. System identification Extracting structural features Damage index 3. Condition assessment Damage detection algorithm APSS-SHM lab

  3. Steel corrosion Concrete erosion Concrete cracking Crack open/closing Fatigue damage Scope of this method Damage Definition “Damage can be defined as changes introduced into a system that adversely affects its current or future performance (Sohn et al, 2003)” APSS-SHM lab

  4. 4 3 2 1 Acceleration 0 -1 -2 -3 -4 0 10 20 30 40 50 60 70 80 90 100 Time (sec) -4 10 -5 10 -6 10 Freq response function -7 10 -8 10 -9 10 0 20 40 60 80 100 120 140 160 180 200 Freq (Hz) Vibration-based SHM Algorithms • Natural frequency changes • Mode shapes • Modal strain energy • Flexibility matrix APSS-SHM lab

  5. Damage Locating Vector (DLV) Method • What is the DLV? (Bernal, 2002) • Load vectors that induce zero stress at the damaged elements • Null space of the change of the flexibility matrices before and after damage • Procedure Normalization Summation Normalized Accumulated Stress (NAS) Calculation of DLVs Structural analysis Data measurements SVD of flexibility change matrix Undamaged &damaged Numerical Model Damage indicator APSS-SHM lab

  6. NAS Spring Example APSS-SHM lab

  7. Decentralized Computing Strategy (Gao) • Damage detection by a segment of structure • Data processing in a segment • Effective and economic data processing • Complete scan using limited sensors • Reliable and robust damage detection by overlapping and comparison APSS-SHM lab

  8. Group 1 Group 2 Group 10 Group 11 16 17 18 19 20 21 22 23 24 25 26 27 28 6 10 14 18 22 26 30 34 38 42 46 50 2 5 9 13 17 21 25 29 33 37 41 45 49 53 3 7 11 15 19 23 27 31 35 39 43 47 51 1 15 1 4 8 12 16 20 24 28 32 36 40 44 48 52 2 3 4 5 6 7 8 9 10 11 12 13 14 Experimental Parameters . . . • Distributed computing strategy: Group 1-11 • Element 8: 40% stiffness reduction APSS-SHM lab

  9. Lab-scale ExperimentsAcceleration Measurement System • Wired accelerometer • PCB 353B33 • Sensitivity: 100 mV/g • Freq. range: 1 – 4,000 Hz • Measurement range: ±50 g • Signal conditioner • PCB442B104: 100x • NI AA filter module: SCXI 1141 • NI DAQ-Pad 6052 E APSS-SHM lab Accelerometers Signal conditioner Computer NI Chassis: SCXI 1411

  10. Results APSS-SHM lab

  11. Demonstration APSS-SHM lab

  12. Assignment • Download SHM lab package • Data set on the truss model • Numerical model • DLV code • http://sstl.cee.illinois.edu/apss/2009labMats.html • Assignment • Due midnight today • One report per group • Send to sjang4@illinois.edu APSS-SHM lab

More Related