Operational Deflection Shape testing (ODS) is the most powerful vibration diagnostic tools an analyst has for understanding vibration problems. Many machines vibrate because of mechanical problems below the machine bearings. Vibration analysis based on bearing measurements doesn't always provide enough information to diagnose problems like loose bolts, cracked welds, foundation problems, resonance resulting in bending and twisting modes of the support structure and other problems.

ODS is an extension of phase analysis. A vibration transducer produces frequency and amplitude information. When a third quantity (Phase) is added to the mix from tens or hundreds of measurement points, the result is one animated movie showing the shape of the machine as it vibrates from linear and non-linear sources. Best of all is the fact that our eyes and brain work very well to diagnose that animated movie.

I have been using ODS testing for many years on consulting jobs and I also offer classes to teach other how to use ODS.

My poll question asks if YOU use ODS testing.
If you use ODS: Choose the only YES answer.
If you don't use ODS: Choose one of the NO answers.
Feel free to leave a comment either way.

Thank you for participating.

Question:
Do you use Operational Deflection Shape testing?

Choices:
Yes, I use ODS testing.
No, I don't use ODS testing because the technique is too difficult to understand.
No, I don't use ODS testing because I don't need it.
No, I don't use ODS testing because I don't own the software.
No, I don't use ODS testing. I have the software but don't know how to use it.
No, I don't use ODS testing because I don't understand how to measure phase.

 

Hi Tony,
I was disappointed in the number of responses your survey attracted. I tried to generate more data by adding the link to the vibration forum. This is where this subject seems to be discussed instead of here.
I really think there are more than 44 people that have an opinion.

Hi Tony,

Is there any article can be shared to understand more about ODS.

Do not read too much into the lack of response. I do not think it really reflects anything.

The members at MaintenanceForums.com do not mind entering discussions, sharing ideas and debating statements - but they rarely submit to anything outside that context.

Personally I would like to see a bigger response however most people enter this site for other activities.

Just my 2 cents from being a forum admin for the past 10 years.

Maybe we should start a Benchmarking or Research forum for this purpose?

Terry O

KJAP,
here is a paper which I presented at a conference in 2000. You may find it of some use.I have been working in this field for over 20 years and have applied the technique to solve problems in a lot of different applications and industries.
Are there any specific applications that you are looking for?
best regards,
Tom Murphy
Tom@reliabilityteam.com

gtfpaper.doc (360 KB, 57 downloads)

I found that the brief post by Tony and the ODS paper by Tom is a good intro to ODS. I doubt I have seen my machinery colleaques use this technique to diagnose machinery problems. Don't really know why. Even in our company's mechanical skill syllabus, I did not read the abbr ODS. Is it a relatively new technique compared to other vibbration techniques?

Hi Josh,
if you are using "relative" in a geological term, then perhaps yes. I have read documents dating back 50 years using this technique.
I first put my hands on software for this in 1988 - then using an HP300 series computer with an IEEE interface to a spectrum analyser.
The hardware took a leap forward about 4 years later and the only real changes since then seem to be just at the edges.
It is an extremely useful tool and I have helped baffled engineers solve many problems with it.

Tom