Edead v1 failures

[johnecon2001 82]

because they're not ment as an adhesive.

A good deadners main purpose is to rid panels of unwanted vibrations that cause and increase noise.

[ANeonRider 3]

Deadeners, by definition, are to reduce vibration (and resonant frequency) by adding mass. A test that tests this would be very welcome. Deadeners only have decent adhesive properties because the application needs them to be applied in car on greater than 90 degree surfaces.

[///M5 2,833]

Why not hang the pieces of sheet metal using the deadeners as adhesive?

That won't be a free-free condition which is necessary.

[///M5 2,833]

The manufacturers (and subsuppliers) do this test in the same setup they measure transmission loss. Doing a sound power measurement at the same time would be cool.

?? damping and transmission loss in the same measurement setup? I'm not sure whether we want clamped edges...

Not sure what the sound power measurement would be used for... but it would be cool, lol. You have access to an intensity probe?

The impact hammer is easy as the vibrometer will trigger an fire the 'autohammer' with an impedance head on the tip, can even do some averaging that way as well. The only difficulty here is consistent boundary conditions when grabbing the sheet metal, really this is my primary concern in the "sheet" consistency. It isn't the easiest thing in the world to get into a near free-free condition and while using a clamping mechanism is fine it has to be repeatable not just in force but in how it affects the target. Obviously a baseline and post deadening scan would be in order for each sample, we can probably post process out the differences but the less you do is better for defending the test on the web.

The book i've been looking into suggests merely hanging the sheet metal by a string that is 'long enough' to not damp the sheet any and not allow vibrations to travel up it to the support. Of course, hanging it by a string would require drilling a hole in the panel.

What magnitude of differences in sheet metal are you talking about? Will it really be of that much difference to affect the measurements?

Sound power would measure the acoustical transfer or transmission loss. It would be possible to see if one is better at isolating outdoor/inside vehicle acoustics. Not a measure of damping at all, but interesting nonetheless. It might make you choose a different type for wheel wells and such. I own an SI probe, but the mics are a bit out of calibration and currently have no way of verifying the phase between them without building a jig. I have some "friends" I could probably borrow one from though.

Not sure what book your reading and am curious. I have tried that actual test, but instead of string we used a bungee like material (which is much better) and did the test that way. The problem is getting the excitation down for the bare metal as it is pretty lively and makes it really tough to do a baseline.

As for the sheet metal, in the fixture above (suspended free-free) it should be fine. Clamped or held differently which really helps in applying a fixed force to it could vary it a lot. I know of some other jigs, but can't copy them or talk about them due to non-disclosures.

[Hobbes26 0]

Sound power would measure the acoustical transfer or transmission loss. It would be possible to see if one is better at isolating outdoor/inside vehicle acoustics. Not a measure of damping at all, but interesting nonetheless. It might make you choose a different type for wheel wells and such. I own an SI probe, but the mics are a bit out of calibration and currently have no way of verifying the phase between them without building a jig. I have some "friends" I could probably borrow one from though.

Not sure what book your reading and am curious. I have tried that actual test, but instead of string we used a bungee like material (which is much better) and did the test that way. The problem is getting the excitation down for the bare metal as it is pretty lively and makes it really tough to do a baseline.

As for the sheet metal, in the fixture above (suspended free-free) it should be fine. Clamped or held differently which really helps in applying a fixed force to it could vary it a lot. I know of some other jigs, but can't copy them or talk about them due to non-disclosures.

The book is Beranek, Noise and Vibration I think (it's at work), bright green cover. I didn't think of using sound power for the transmission loss measurement, as i'm only familiar with the method of using two reverb rooms, etc.. But I think TL would be one of the things that we should measure in these tests.

A bungee material, at first thought, might damp the vibrations too much...?

[///M5 2,833]

You always want to remove as much of the fixture as possible when looking at modal bending a damping measurements. I string is too rigid, while a bungee allows more freedom. It will depend on the frequency range of interest as well though.

[Hobbes26 0]

You always want to remove as much of the fixture as possible when looking at modal bending a damping measurements. I string is too rigid, while a bungee allows more freedom. It will depend on the frequency range of interest as well though.

I know that - I'm just not sure (haven't looked into it much yet) of the frequency dependency of the string/bungee and what we want to have. Man this is getting complicated... lol.

[///M5 2,833]

If it wasn't complicated I would have done it a while ago. Being that I will have to defend the results I want them to be bulletproof.

[stratusrt01 0]

I had edead v1 on my trunklid and around where we cut out the rear deck.

I say had because the 1st time it got over 90 degrees, I found it stuck to the top of my amps and my subs. It just fell off. I have Cascade V-Block now, and no problems whatsoever.

[Hobbes26 0]

If it wasn't complicated I would have done it a while ago. Being that I will have to defend the results I want them to be bulletproof.

LOL... I guess that's why we're having this discussion then! If the results are questioned that only helps us to figure out how to overcome the limitations of the measurements. Although that does make for more work, seeing as you'll probably end up remeasuring everything again.. haha

So I assume that you're not aware of any ISO/ANSI/ASTM/etc. standard that has been developed for measuring what we want to measure... I haven't been able to find anything. Perhaps there is something in the european standards (hopefully they'd be in english)?

Anyways, as far as variation in samples of sheet metal goes, what frequencies are most affected? At low frequencies where we can excite single modes, is there a lot of variation in those resonance frequencies? What variation can we allow in our measurements?

General questions:

What frequencies are we most interested in? Lower / Middle / Higher / Full Bandwidth of Human Hearing? Perhaps we can cancel out the higher frequencies, seeing as those will be most easily damped, but we probably need to find an upper limit. And what frequencies are generated in the car - vibration from the road, noise from the exhaust, wind noise, etc...

What shape and size of panel (and gauge/thickness) ? We can 'easily' calculate (and model) theoretically the response of a square panel given the dimensions, stiffness and density of the material. At least to make sure we're measuring what we expect. Although I'm not sure how to calculate it when we have the damping material applied.

I think we've established that we want to measure both Transmission Loss as well as Damping. I haven't seen the output of a vibrometer - are you able to measure in 2 dimensions? Is there an easy way to show the difference between the damped and undamped measurements and compare them (for the layman (or Lehman ))?

And most importantly, can we abstract this to the real world? There will have to be disclaimers regarding stuff such as application of the material onto a clean surface, something on the location of the material in the car, how the car is a complex structure, etc.

Edited August 21, 2007 by Hobbes26

[///M5 2,833]

So I assume that you're not aware of any ISO/ANSI/ASTM/etc. standard that has been developed for measuring what we want to measure... I haven't been able to find anything. Perhaps there is something in the european standards (hopefully they'd be in english)?

Anyways, as far as variation in samples of sheet metal goes, what frequencies are most affected? At low frequencies where we can excite single modes, is there a lot of variation in those resonance frequencies? What variation can we allow in our measurements?

What frequencies are we most interested in?

What shape and size of panel (and gauge/thickness) ? We can 'easily' calculate (and model)

I haven't seen the output of a vibrometer - are you able to measure in 2 dimensions? Is there an easy way to show the difference between the damped and undamped measurements and compare them (for the layman (or Lehman ))?

And most importantly, can we abstract this to the real world? There will have to be disclaimers regarding stuff such as application of the material onto a clean surface, something on the location of the material in the car, how the car is a complex structure, etc.

Man, you are trying to speed this whole thing up aren't you

There are no current standards and actually none being developed. The industry really only cares about TL which there are 3+ different standards

As to your variation question, lets ignore this one until we decide on a fixture and then I can actually test the differences. With the right fixture and chosen media we should be able to work around it. Fixturing is to measurements what location is to real estate.

Typically the SAE guys are most interested in areas below 400hz.

I can't easily model anything. I am an FEA noob, but I can load an FE model into the vibrometer and make measurements and verify a model is right easily. A simple piece of metal however is a very easy thing for someone with any FE experience to whack out.

I have a 3D scanning vibrometer, meaning I can measure X,Y,Z vibration and then scan the laser across the surface with a high point density. Regularly this is used to verify FE models as well as measure experimentally.

Most definitely we can abstract this to the real world. Everyday the automotive manufacturers do. It is also very easy to compare the damped and undamped measurements.

[Acidburn 10]

So I assume that you're not aware of any ISO/ANSI/ASTM/etc. standard that has been developed for measuring what we want to measure... I haven't been able to find anything. Perhaps there is something in the european standards (hopefully they'd be in english)?

Anyways, as far as variation in samples of sheet metal goes, what frequencies are most affected? At low frequencies where we can excite single modes, is there a lot of variation in those resonance frequencies? What variation can we allow in our measurements?

What frequencies are we most interested in?

What shape and size of panel (and gauge/thickness) ? We can 'easily' calculate (and model)

I haven't seen the output of a vibrometer - are you able to measure in 2 dimensions? Is there an easy way to show the difference between the damped and undamped measurements and compare them (for the layman (or Lehman ))?

And most importantly, can we abstract this to the real world? There will have to be disclaimers regarding stuff such as application of the material onto a clean surface, something on the location of the material in the car, how the car is a complex structure, etc.

Man, you are trying to speed this whole thing up aren't you

There are no current standards and actually none being developed. The industry really only cares about TL which there are 3+ different standards

As to your variation question, lets ignore this one until we decide on a fixture and then I can actually test the differences. With the right fixture and chosen media we should be able to work around it. Fixturing is to measurements what location is to real estate.

Typically the SAE guys are most interested in areas below 400hz.

I can't easily model anything. I am an FEA noob, but I can load an FE model into the vibrometer and make measurements and verify a model is right easily. A simple piece of metal however is a very easy thing for someone with any FE experience to whack out.

I have a 3D scanning vibrometer, meaning I can measure X,Y,Z vibration and then scan the laser across the surface with a high point density. Regularly this is used to verify FE models as well as measure experimentally.

Most definitely we can abstract this to the real world. Everyday the automotive manufacturers do. It is also very easy to compare the damped and undamped measurements.

I'm taking an intro to FEA class this semester. If we cover anything that I think would be useful, I'll be sure to let you guys know.

[Rudeboy 152]

Most definitely we can abstract this to the real world. Everyday the automotive manufacturers do. It is also very easy to compare the damped and undamped measurements.

Don't they do it on part by part basis?

I can tell you that transmission loss testing using ASTM E756@ 200 Hz is what has been used by after-market sound deadener manufacturers. This started with Dynamac Control and I have been told by more than one source that their numbers were achieved by non-standard methods. I believe the results reported by competitors have been "invented" using DC's as a starting point.

Tom Lewis at Damping Technologies suggested Oberst bar testing when we were discussing this same topic, but said the results really couldn't be made meaningful for this application. His basic point was that using twice as much of any product would roughly double the effectiveness and controlling for variations in thickness and density would be more trouble than the results would be worth. This led to my conclusion that:

• Adhesive quality is important
  
• Foil thickness is important
  
• Mass is important
  

and that has been generally good enough except for those who have just wanted to cast doubt for their own reasons.

Something else to consider is the variability of these products, even samples taken from the same batch and within inches of each other. When weighing and measuring, I take 4-6 pieces from as far away from each other as possible and average. The variations are large. Finding a representative sample will be important.

I'm not trying to discourage this effort at all - I support it enthusiastically and am following your progress closely.

Edited August 22, 2007 by Rudy

[DBfan187 0]

mine's been falling off of my door for the past year, has also left this brown marks around it that look like chit.

[Rudeboy 152]

mine's been falling off of my door for the past year, has also left this brown marks around it that look like chit.

Brown residue means it was the asphalt version. They've improved it so it falls off cleanly now

[Acidburn 10]

mine's been falling off of my door for the past year, has also left this brown marks around it that look like chit.

Brown residue means it was the asphalt version. They've improved it so it falls off cleanly now

Well, atleast they're making improvements.

[///M5 2,833]

Most definitely we can abstract this to the real world. Everyday the automotive manufacturers do. It is also very easy to compare the damped and undamped measurements.

Don't they do it on part by part basis?

I can tell you that transmission loss testing using ASTM E756@ 200 Hz is what has been used by after-market sound deadener manufacturers. This started with Dynamac Control and I have been told by more than one source that their numbers were achieved by non-standard methods. I believe the results reported by competitors have been "invented" using DC's as a starting point.

Tom Lewis at Damping Technologies suggested Oberst bar testing when we were discussing this same topic, but said the results really couldn't be made meaningful for this application. His basic point was that using twice as much of any product would roughly double the effectiveness and controlling for variations in thickness and density would be more trouble than the results would be worth. This led to my conclusion that:

• Adhesive quality is important
  
• Foil thickness is important
  
• Mass is important
  

and that has been generally good enough except for those who have just wanted to cast doubt for their own reasons.

Something else to consider is the variability of these products, even samples taken from the same batch and within inches of each other. When weighing and measuring, I take 4-6 pieces from as far away from each other as possible and average. The variations are large. Finding a representative sample will be important.

I'm not trying to discourage this effort at all - I support it enthusiastically and am following your progress closely.

I have never worked with an aftermarket sound deadening company actually using E756 but am aware of it. I have worked with a lot of them as well.

I am not a fan of Oberst testing, it was a method we proposed at my previous employer. Measuring damping directly is a much better method and applicable in my book. Sure it will have a different effect on different parts, but the end results will be comparable.

Think of companies like MSC (owns the patent on quiet steel) and how they sell/propose their solution. Sure it is regularly tested on a part by part basis, but a generic sample is used to get in the door and go down the exploratory road of whether or not it will indeed quiet the vehicle. In my book doing similar testing is a valid way of determining the effect of the dampening material. As you state, it comes down to mass, adhesive and foil thickness and not much else.

I find your effort comment funny, currently this is a thread about how eDead sucks and now we have an effort. I am more than willing to undertake some of the testing though, but this conversation will go much further before then.

[///M5 2,833]

mine's been falling off of my door for the past year, has also left this brown marks around it that look like chit.

Brown residue means it was the asphalt version. They've improved it so it falls off cleanly now

Well, atleast they're making improvements.

LOL

[Hobbes26 0]

Most definitely we can abstract this to the real world. Everyday the automotive manufacturers do. It is also very easy to compare the damped and undamped measurements.

I meant that as a comment to Don's comment about the naysayers that refute the tests that he's done as being non-applicable to the real-world conditions of a car.