Vibration Perception 2

[eureka]

I have a graph that has plotted on the x-axis Dynamic Amplitude and on the y-axis Frequency.<br><br>On the graph are two lines: SNAME line and CDG &quot;D&quot; line.<br><br>They divide the graph into Acceptable and Not Acceptable areas of vibration perception.<br><br>There are no references sited.&nbsp;&nbsp;Can anyone shed light on references for the SNAME line and CDG &quot;D&quot; line?

 

[brin]

I don't know, but ask someone at SNAME (Society of Naval Architects and Marine Engineers)

 

[brin]

also, could you provide a bit of information on what you are trying to measure?&nbsp;&nbsp;eg:&nbsp;&nbsp;building vibration, bus & train, etc.

 

[eureka]

We have been asked by our client to quantify the vibration due to large compressor trains on some offshore platforms.&nbsp;&nbsp;The workmen sometimes complain that the vibrations are excessive.&nbsp;&nbsp;We can measure the frequency and the dynamic amplitude.&nbsp;&nbsp;We can see where these fall on the graph.&nbsp;&nbsp;We are interested in finding the source of the two lines dividing the areas on the graph in order to see what criteria was used for establishing these lines.&nbsp;&nbsp;Ultimately, we need to determine if these complaints are justified, and if so, we will need to make recomendations to minimize the vibrations to an acceptable level.

 

[noise]

Habitability vibration criterion are provided in SNAME T&R Bulletin 2-25 and ISO 6954.

 

[TimC]

In the off-chance that you haven't considered this, when you take your measurements, be sure to look at the phase relationships between the different compressors. It may be that when the &quot;workmen sometimes complain&quot; there are two or more compressors that are causing &quot;beats&quot;.

 

[Hatch]

If you want to quantify the wholebody vibration (which is what you have for standing workers (or seated), ISO 2631 details the measurements and evaluation of wholebody vibration.<br><br>I have applied the criteria several times and found that the results correlate very well with my own response.&nbsp;&nbsp;i.e. if it is rated very uncomfortable, I do not want to be standing in that area very long.<br>