Basic NVH Help

[wantolearn]

I'm a product engineer involved with exhaust systems and would like to obtain a better understanding of how to apply the fundamental theory to the practical application. I've had undergraduate and graduate courses in Mech. Vibration and yet, I'm finding it challenging to interpret and/or pull out the necessary data to make good engineering decisions. While I feel a have a general understanding of modal analysis and acceleration data, I'm somewhat lost in evaluating and interpreting the various methods in which the data is reduced (PSD's, waterfall plots, RPM vs Freq., etc.). I have NVH support at my place of employment, however, feel this is something critical to my success and therefore need to learn personally.

Are there any texts, seminars or classes offered with practical examples that can help me in this arena? Again, I'm comfortable with the theory and struggling with the data interpretation.

 

[GregLocock]

Yes. I strongly recommend the NVH reated short courses run by ISVR at Southhampton University in the UK.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[SomptingGuy]

I've heard good reports from the practical course given by Cranfield too.

 

[Rob45]

Depends on where you're located.
If by chance you were in SE Michigan, you'd find some of the courses at Wayne State Univ. to be very useful.
Depending on just how you're "involved" wtih exhaust systems, you'll have different requirements, I think: if you're designing or developing mufflers or other exhaust system components, you might be as interested in vibration and structural issues as much as in the acoustics side of things.
If you're involved in the vehicle side, and are the customer who's buying the exhaust system, you'll possibly be more interested in sound quality issues and overall (exterior) levels.
In either case, you'll want a good understanding of your vehicle, how its powertrain produces noise inputs, how the cabin responds to the those inputs, and the sound paths from exhaust to cabin.
Also, speaking from my own experince here, I'd say you'll find it very important to be able to sort out actual exhaust noise from noise having a similar character but produced by some other source, e.g., the air intake; or between what might appear to be airborne noise (and therefore treatable with the muffler) but which is actually structurally transmitted through e.g. a structurally-deficient bracket or frame member.

Note also that companies such as B&K and Head Acoustics offer very useful short courses in sound and vibration, and there is at the B&K website a great deal of good information that can be downloaded.

Finally, let me suggest that you find someone you work with who is familiar with this field, and ask him to help you.
It's what we do.

 

[wantolearn]

Thank you for your insight. I'm focusing most of my attention toward vibration due to the durability concerns/issues experienced in the past. The systems I release are closer to the manifold (i.e. upstream). I'm in SE Michigan. Any input regarding The Vibration Institute? Other postings on this website have referred to it.

 

[Rob45]

Want:
I've never heard of the Vibration Institute, but I would strongly recommend the B&K website and checking out the current course offerings at Wayne State.

Or LMS: their work focuses a bit more on structure than on acoustics, although you'll find the "hot end" also has a generally poorly-understood effect on vehicle NVH.

 

[wantolearn]

We'll do. Thanks again for you input!

 

[adityak]

I was at Wayne State for my Master's in Acoustics & Vibration. The courses are well designed for theoretical insight of the subject. The advisor's have healthy experience from their consulting work & were all funded in the good weather days. So, they encourage discussion of practical applications.

But if you want to avoid the theory & focus just on practical applications, you might wanna consider B&K, LMS, Vibrant Technologies has good vibration courses.

Other than that, does anybody has a suggestion on a sites that'd have a collection of case studies in Acoustics & Vibraiton?