Michelin problems at Indy 2005

[WhiteBlue]

Sorry WhiteBlue...I'm just a little prone to consiracy theories since the Michelin/Indy fiasco

Yep, many people seem to have such problems. They fail to recognize that the Michelin problem was a physical problem caused by resonance. The side wall design was incited by an eigen frequency and nothing but a complete redesign would have cured that problem.

But the little business problem of the Austin project was not technical. It was a confrontation of two sides that both thought they knew all about business and negotiations. As it turns out one side did not.

[strad]

WB said:

They fail to recognize that the Michelin problem was a physical problem caused by resonance. The side wall design was incited by an eigen frequency and nothing but a complete redesign would have cured that problem.

What have you been smoking now?

[WhiteBlue]

WB said:

They fail to recognize that the Michelin problem was a physical problem caused by resonance. The side wall design was incited by an eigen frequency and nothing but a complete redesign would have cured that problem.

What have you been smoking now?

It is not being smoked. You absorb it from books and it is called the science of mechanics and particularly of the dynamic variety. People who cared to study the Michelin communications about the 2005 disaster know that the company undertook rig simulations based on the data from Indianapolis and discovered that even their backup design with a tougher compound did not make it on a dynamic test rig. The side wall construction simply did not stand the dynamic forces induced by the vertical g loads.


Have a look at the evidence of side wall failure.

Btw I do not understand what the Michelin case has to do with the Austin race. I very much doubt that North and South American F1 fans will be substantially influenced in their ticket purchasing decisions by the 2005 event. There are a lot more important factors than that old story. The location of the track close to Mexico and Central America will have a far greater impact IMO.

[bill shoe]

Interesting that a technical discussion about Michelin at Indy 2005 has broken out in this thread. I'll take it.

What is an eigen frequency as it relates to a tire sidewall? Or a resonance as it relates to the sidewall? I mean what is the mode shape or wave form or something descriptive?

I have no inside info on the Michelin failures. I just remember that as a fan who went to the race I was manipulated because Michelin knew they would not race, yet kept that info secret for more than a day because it suited their PR purposes. Ticket refunds months later did not make up for that.

I remember that Ralph Schumacher had a mysterious Michelin failure the year before at Indy (2004?) and nobody knew why. Then the diamond-grinding of the oval surface was done in the winter of 2004/05. Then Michelin had consistent failures at Indy 2005. The diamond grinding sucked, and it was a convenient thing for Michelin to blame, but I do not see any actual evidence that it was the cause of the problem.

Perhaps Michelin overlooked the clues from their 2004 failure and then found it convenient to blame the diamond grinding in 2005.

[bhall]

Not this again.

[strad]

Means the sidewall flexed.

[WhiteBlue]

What is an eigen frequency as it relates to a tire sidewall? Or a resonance as it relates to the sidewall? I mean what is the mode shape or wave form or something descriptive?

Michelin are intelligent enough to dimension the side wall for the basic forces that occur during the standard race operations but there were in the middle of a tyre war and they needed an advantage over Bridgestone. It is well known that the Michelins had a different side wall stiffness compared to the Bridgestones which lead to different properties with regard to cornering. The traction was supposed to be superior.

But the design came with a weakness on tracks with high G forces. Michelin had tyre failures in Turkey and Spa before they hit the Indianapolis disaster. Both tracks have high G forces including vertical components. Michelins report said that their race tyre and the backup tyre both failed in dyno tests once they tested them with the Indy telemetry track data. The issues that they must have missed were of dynamic nature and not so basic things as lateral acceleration. Those dynamic loads must have been well known.

But there were obviously dynamic forces which they had not taken into consideration. Those forces must have exceeded the strength of the fibre construction. The biggest difference in Indianapolis was the long banked corner which generated high vertical G loads. Those G loads must have been the trigger for the failures. But it could not have been as simple as just the loading. Michelin was too clever to forget that factor. On the other hand resonance is a well know reason for force amplification. Compression from vertical G loading would have created a running wave at the side wall as the tyre rotated through the compression zone. The rational explanation why this wave form destroyed the construction is resonance. Resonance happens when an oscillating system is excited at the natural (eigen) frequency or multiples of that frequency. Michelin must have been unaware of a match between a resonance frequency and the wave from vertical loading. This also explains why only a massive speed drop through the banked corner could have stopped the failures. It would have moved the exciting frequency out of the critical rev band.

[Jersey Tom]

I'm 99% certain it didn't have to do with "resonance."

Anyway. How did this even spawn off the Austin thread??

[WhiteBlue]

I'm 99% certain it didn't have to do with "resonance."

Well, this is your opinion. Resonance is a perfect explanation why the Michelins with a different side wall stiffness failed and the Bridgestones did not.

Perhaps you give us your explanation why the side wall construction failed catastrophically sometimes within the first two laps. And the strange thing is that Michelin could reproduce the problem on their dynamic test rig. After the tests they said that nothing could be done short term except dropping the speed massively through the banking.


If you are 99% certain you must have a pretty good theory to fit the unusual circumstances of this bad surprise for Michelin. The company is probably the most experienced manufacturer of auto racing tyres. Their engineers must have been caught out by something very unusual.

[hardingfv32]

WhiteBlue

Exactly what is a "dynamic test rig"? A F&M machine as discussed in the Pirelli thread?

Any example of such a machine that would to good enough for accurately simulate race tire operating conditions?

Brian

[DaveW]

This topic has been discussed endlessly in these forums.

I have no idea if resonance was the cause of Michelin rear tyre failures in 2005, though I would listen to the professionals on the subject.

I would also point out the following:

1. 2005 was the year that F1 tyres were required to last a whole race distance.

2. It may not please US fans, but Michelin overwhelmingly won the F1 "tyre championship" of 2005.

3. The Indy. circuit had been diamand grooved after grip problems were found after a resurface.

4. Both Firestone (Bridgestone) & Goodyear encountered tyre life issues when first running on grooved tracks.

5. Michelin did not know about the surface until the F1 circus arrived in town - not really an excuse, because I don't think they would have predicted a problem until they had actually tested.

[Jersey Tom]

I'm 99% certain it didn't have to do with "resonance."

Well, this is your opinion. Resonance is a perfect explanation why the Michelins with a different side wall stiffness failed and the Bridgestones did not.

Not my opinion, just what I'm told. Not long ago (at some point this year) this topic came up in conversation with an engineer.. let's say quite familiar with Michelin F1 tires of that time frame.

He mentioned what the issue had been. To be honest I don't recall what the specifics, but it was pretty unsurprising. Nothing fanciful, and it would have hit my memory if it was some "resonance" thing.

The company is probably the most experienced manufacturer of auto racing tyres. Their engineers must have been caught out by something very unusual.

This is just naive. Most experienced? By what measure? Plenty of equally "experienced" tire companies out there. Does Michelin do good work? Absolutely. They have some fine products out there, both racing and consumer. They also have some crap products. They've beaten other manufacturers, and they've also been beat pretty handily themselves.

Putting any supplier, manufacturer, or competitor on a pedestal of being infallible is silly.

[FW17]

3. The Indy. circuit had been diamand grooved after grip problems were found after a resurface.

Is a diamond grooved surface an allowable FIA spec?

[WhiteBlue]

WhiteBlue

Exactly what is a "dynamic test rig"? A F&M machine as discussed in the Pirelli thread?

Any example of such a machine that would to good enough for accurately simulate race tire operating conditions?

Brian

I can't tell you what kind of test rig they have. All I know is derived from their official statements. There was a discussion with the FiA why they did not send in a backup tyre. The FiA perhaps suspected that there was no backup. Michelin answered that question by saying that the backup tyre also failed on the dynamic test rig which was set to the data aquired from the circuit. Hence it made no sense to air ship these tyres.

[WhiteBlue]

Not long ago (at some point this year) this topic came up in conversation with an engineer.. let's say quite familiar with Michelin F1 tires of that time frame.

He mentioned what the issue had been. To be honest I don't recall what the specifics, but it was pretty unsurprising. Nothing fanciful, and it would have hit my memory if it was some "resonance" thing.

So we can cap that up by saying: You don't know what it was. Not a very convincing point against the resonance theory. I would not take every bit of shop talk by "experts" dead serious.

The company is probably the most experienced manufacturer of auto racing tyres. Their engineers must have been caught out by something very unusual.

This is just naive. Most experienced? By what measure? Plenty of equally "experienced" tire companies out there. Does Michelin do good work? Absolutely. They have some fine products out there, both racing and consumer. They also have some crap products. They've beaten other manufacturers, and they've also been beat pretty handily themselves.

Putting any supplier, manufacturer, or competitor on a pedestal of being infallible is silly.

I have not said they were infallible. History shows they weren't. But they were at the cutting edge of the technical competition and they missed one small bit which had something to do with dynamic vertical loading. Michelin won the last tire war in F1 (only six years ago) and is also by far the most successful brand in Le Mans sports cars. Those are very prestigious fields of competition. I would actually say they are the pinnacle of auto racing. Before you shoot my assessment down you could perhaps give an opinion which competitor performed better than Michelin in 2005 and substantiate that claim.