engine and ride vibration calculation

[sleighty]

Hi,

I'm sure this question will seem pretty basic for most here but I'm not particularly familiar with vibration and would really appreciate pointing in the correct direction.

I'm trying to set up a test whereby i will test different sensors using different vibration frequencies. The idea is to attempt to find if the sensors (which will eventually be used for race vehicle acquisition) read the same whether they are in vibration or steady. The problem is that I want to calculate the realistic vibration. I need to work out firstly, engine vibration from a theoretical engine that im basing the test upon. Secondly i need to work out the road vibration or wheel induced vibration. I know the potential gearing, wheel speeds, wheel sizes and rpm.

How might I go about doing this, any help is appreciated.

Thanks

 

[IRstuff]

Sounds like a lot of work for a hypothetical. Why not use the test PSDs in something like MIL-STD-810?

TTFN
faq731-376

 

[sleighty]

it does but i wanted it to be quite specific to the application.

I'm not looking to work out the exact vibration as i know you would have to work out the vibration through materials etc.

Is there a relatively simple method of working out what vibration would potentially come from the engine/gearing and the road due to bump??

Thanks

 

[IRstuff]

Not without knowing the suspension response. However, MIL-STD-810's vibration profiles represent the vibration imposed on cargo from a range of trucks driving over a variety of road surfaces.

Your best answer is probably to instrument a variety of vehicles driving over the specific surface of interest, envelope the response, and generating PSDs from the measured data.

TTFN
faq731-376

 

[GregLocock]

4 cylinder SI engine max vib say 20g rms at 2nd order at 6000 rpm, on the head.

typical body vibrations are less than 1g, don't have a good feel for the numbers.

typical suspension vibrations might be 10g peak in a curb strike, very roughly.



Cheers

Greg Locock


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