Hi, I have instrumentet a concrete bridge with 6 accelerometers, and I have roughly a plan for what to do in order to implement a predictive maintenence monitoring system;
- Modal identification using Frequency Donaim Decomposition(FDD)
- Use the modal parameters to compare with and update the FEM-model so that the stiffness, mass and damping is closely fitted to the real bridge.
- Predict structural load over time using analysed accelometer data as intput to the FEM model.
So, is FDD a reasonable method to use? The accelerometers are sending measurement data continously, so if needed i can treat several days of measurement data.
Any thoughts or comments will be greatly appreciated.
Regards, Ole-Martin
Hei Ole-Martin
The above sounds like a good approach for model QA as well as for Test/Test QA where you compare vibration patterns over time.
From what I have understood from people working with Structural Health Monitoring (never worked with it myself), a good way to detect changes is to look at local transfer functions between closely located sensors, i.e. SensorX/SensorY, as these tend to be the more sensitive to change than is modal natural frequency and damping.
With your sensor signals, you should be able to do this as well as what you write above.
Sincerely
Claes
Hei
For hwat it is worth. You might like these. They are not related to SHM but capture some aspects of interest for Model QA
Article SM98-124/626 Force Measurements during Vibration Tests with ...
Article FE Model Correlation & Mode Shape Updating using Qualificati...
Presentation Analysis Technology:; A discussion on some of the fundamentals
http://qringtech.com/learnmore/why-simulate-measure-correlate-automate/
/C
Hi Ole-Martin,
Good job, but I agree with Huynh as well as you need more sensors to monitor your structure in better way.
Here is the link of my article ,Hope is helpful:
Article SVM Multi-Classification of Induction Machine's bearings def...
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