Sign up Calendar Latest Topics Donate
 
 
 


Reply
  Author   Comment  
RHW2ND

Avatar / Picture

Member
Registered:
Posts: 30
Reply with quote  #1 
Our software is not fully developed, and we are not able to convert velocity or acceleration to displacement. What is the formula for integration?
Lost all my books in boxes
Thank you for any help in this matter
Bob W
John from PA

Sr. Member
Registered:
Posts: 963
Reply with quote  #2 
Is something like https://www.stiweb.com/Vibration_Calculator_s/104.htm what you need or are you after the actual equations (assuming sinusoidal motion)?
OLi

Sr. Member
Registered:
Posts: 1,918
Reply with quote  #3 
Best IMHO is actually to do the FFT on the raw signal and then convert from A to B in the "frequency plane", it may be argued what it looks like if you then do the inverse FFT do get a converted TWF to look at but it may be another can of worms, good luck it is not as bad as it sounds ;-)
__________________
Good Vibrations since early 1950's, first patented vibrometer 1956 in the US.
http://www.vtab.se
RHW2ND

Avatar / Picture

Member
Registered:
Posts: 30
Reply with quote  #4 
Thank you John from PA and Oli.
My son insisted on the difficulty of accuracy, as he took statistical analysis among other math courses.
I thought I remembered  a standard formula but it might have been a program which John shared with us. (its been about thirty years ago).[smile]

We are monitoring several operating room's where they use electronic microscopes for brain surgery, 24/7 every ten minutes. We are hoping the programmer gets this worked out this week. Otherwise we won't have the displacement readings for about 4 four accelerometers.

Bob W
John from PA

Sr. Member
Registered:
Posts: 963
Reply with quote  #5 
Quote:
Originally Posted by RHW2ND

I thought I remembered  a standard formula but it might have been a program which John shared with us. (its been about thirty years ago).[smile]
Bob W


Rather than go to the trouble of typing in the standard equations for sinusoidal motion I have scanned the backside of two of the slide rule calculators (Dymac & Endevco) that were common many years ago (I note the Endevco is copyright 1971).  The various equations are in the lower left corner of each slide rule and differ slightly in format depending on which you use.  I've attached the scan as a PDF file.

As you likely know watch out for the units on g's.


 
Attached Files
pdf Scan.pdf (524.29 KB, 19 views)

RHW2ND

Avatar / Picture

Member
Registered:
Posts: 30
Reply with quote  #6 
OMG I forgot I had one of those slide rules it's buried with all my papers.
RHW2ND

Avatar / Picture

Member
Registered:
Posts: 30
Reply with quote  #7 
we have over a thousand readings to integrate
John from PA

Sr. Member
Registered:
Posts: 963
Reply with quote  #8 
Quote:
Originally Posted by RHW2ND
we have over a thousand readings to integrate


Based on your previous...it should be an easy task.

Quote:
Originally Posted by RHW2ND

My son insisted on the difficulty of accuracy, as he took statistical analysis among other math courses. 

Bob W
Walt Strong

Sr. Member
Registered:
Posts: 889
Reply with quote  #9 
I hope all of the 1000 readings are single frequency and not overall levels, otherwise you are not going to convert!

Walt
RHW2ND

Avatar / Picture

Member
Registered:
Posts: 30
Reply with quote  #10 
they are fft's which actually can convert to mills, then have to be entered for a time line report???
Hoping programer an get this fixed this week.
OLi

Sr. Member
Registered:
Posts: 1,918
Reply with quote  #11 
I monitored a MRI (on our designed seismic mount) during rock blasting as close as 12m from it. It got 1T (long time ago) superconductive super cool magnets, it was fun, the fat screens of the time were not LCD but got distorted by the magnetic field and was only possible to use in certain angles or it got bananas, long time ago.....
__________________
Good Vibrations since early 1950's, first patented vibrometer 1956 in the US.
http://www.vtab.se
RHW2ND

Avatar / Picture

Member
Registered:
Posts: 30
Reply with quote  #12 
What type of seismic mount did you use
OLi?
OLi

Sr. Member
Registered:
Posts: 1,918
Reply with quote  #13 

Classic spiral steel springs, in one case standard iron where the device had to be recalibrated in another case stainless springs and was plug and play albeit you need to hoist it and set it down.... KISS[cool]

In one case it was the blasting of a rock cavern near machine in Stockholm (12m bedrock!) in the other case it was the hospital air-condition AC on umpteenth floor in US where the MRI was "near" so they had to drive up with a portable device n a trailer in the yard to keep the delivery as the pictures got blurred from the AC floor vibration. After isolation mounting, pictures clear as the sky, not clear as mud anymore. Great fun![smile]
You know that center tube hangs in glassfiber "fishing rods" frozen to -200 and more (less) deg C by I think cryogenic helium or similar in the same circuit as the super conductive magnets so there are strict vibration limits for shock from blasting. Part from the blurring problem from external vibration during measurement but it is a fantastic type of device. 


__________________
Good Vibrations since early 1950's, first patented vibrometer 1956 in the US.
http://www.vtab.se
Previous Topic | Next Topic
Print
Reply

Quick Navigation:

Easily create a Forum Website with Website Toolbox.