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User:Crecasens

1,564 bytes added, 10:47, 31 January 2013

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== Vibrations ==

Radar technology can also be used to make non contact remote measurements of building vibrations with high precision level.

This is a very interesting application on the construction area.<br>

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp; Measurements set up: IGEP RADAR LAMBDA eith special software is placed on the ground facing the top of the viaduct at a distance of 15m<br>

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 The next figure show the graphic obtained at the time the train was passing over the bridge. The graphic represents the relative position of the top of the viaduct over the ground. Yes, the structure moves 2mm, will you take the next high speed train? Do not worry this is normal and you do not have to worry about it, this vibration response has a normal profile.

The advantage of this kind of measurements is that tdepending on the vibration wave profile engineers can detect structure problems, in the same way a doctor can check if your hearth is OK by lookintg at an EKG.<br>

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Vibration wave graph obtained on the measurement. It can be clearly shown the high precision of the measurement<br>

Y Axis: Relative movement between viaduct top and ground in millimeters

X Axis. Time in seconds

We can see from the graph that the radar technology has a precision better than 50 micrometersY Axis: Relative movement between viaduct top and ground in millimeters

X Axis. Time in seconds

<u>'''We can see from the graph that the radar technology has a precision up to 50 micrometers'''</u>

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [[Image:AVEMESURA-3-Bs.jpg]]

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 2D graph representing frequency domain measurements.<br>  Y Axis: Represents the sample number of the FFT of the captured data so, it is the Frequency axis X Axis: represents the Captured file number, so it is the Time axis This is another way to present the results, by representing all the measurements FFT. It can be seen the peak due to the viaduct top reflection, and in the mid measurements it can be noted the vibration during the time the train is passing.   The figure below is a 3D representation of the same: FFT module of all the measurements. Look at the vibration in the central area.  

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [[Image:AVEMESURA-3s.jpg]]

<br> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 3D graph representing frequency domain measurements.

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Carles Recasens

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