Tracy Question

[TedN]

In Paul's latest column (http://www.thestar.com/NASApp/cs/ContentServer?pagename=thestar/Layout/Article_Type1&c=Article&cid=1094120588988&call_pageid=968867497088&col=969048871196) , he says the following about the Montreal race ...


Three laps into the first practice session on Friday, the monocoque tub that houses my seat split apart — simply from running over curbs during a normal lap around the track.

Then in the first qualifying session, my gearbox split open — also from just running over the curbs.

Though I managed to turn some laps in Saturday's qualifying session, the car started to handle funny.

When I pulled in, the team found my engine block was cracked.

And after the race, not only was my front end cooked, we also discovered that the replacement monocoque had split apart on the car.

That amount of hardware damaged on one weekend is quite a stroke of misfortune, especially when most of it happened without even hitting anything.

It's quite a change from last year, when everything from qualifying to the races themselves seemed to go my way.

Burning through those monocoques means I'll be racing at Laguna Seca without a spare car.


I didn't realise things were this bad for Tracy. Seems like a potenially frightening situation. Is it an indication the chassis are too old?

Ted

[TravelGal]

I didn't realise things were this bad for Tracy. Seems like a potenially frightening situation. Is it an indication the chassis are too old?

Ted

I've been wondering exactly the same thing. Not only about the chassis. Last year there were virtually no mechanical breakdowns. At least, not the number we are seeing now. It's no wonder they are wanting a new deal for 2006. It will give a chance to revamp the cars' pieces/parts. And a chance to save up for it. ;) (As if they ever do THAT!)

[RTKar]

Time for some new specs, the guys are driving some pretty old stuff.

[JoeBob]

Some guys might have old stuff, but there are also guys out there with brand new stuff. Lola is still producing cars and parts.

[Railbird]

The current Champcar formula makes for some big heavy cars leaping those F1 kerbs. When formulating the next spec I hope they take this into consideration.

[nrc]

The curbs in Montreal didn't look any more severe to me than the curbs in Australia and they bash those things relentlessly.

[Peter Venkman]

In Paul's latest column (http://www.thestar.com/NASApp/cs/ContentServer?pagename=thestar/Layout/Article_Type1&c=Article&cid=1094120588988&call_pageid=968867497088&col=969048871196) , he says the following about the Montreal race ...



I didn't realise things were this bad for Tracy. Seems like a potenially frightening situation. Is it an indication the chassis are too old?

Ted


I think it means that "running over the curbs" means different things to different people.

Actually, I had a spirited discussion about the fatigue life of a racing tub with some guy that writes an occasional column for the rag, "Autoweek".

A honey comb structure, which is the primary construction of a modern race car comprises a sandwich construction of carbon fiber sheet skins on both sides of an aluminum or Kevlar honey comb core. The cars are designed to take expected bending and torsional loads for a reasonable lifetime, which is primarily considered its fatigue life (amount of times that the structure is cycled, either in bending or torsion).

Carbon fiber is a miracle material for strength and stiffness, but in almost all applications, its multiple layers, or plies, bonded together with an adhesive.

As the structure is flexed (which is being done not only by running around the track, but also by the vibration frequencies of the suspension inputs, the engine and gearbox, and anything else that can flex the structure.) the carbon fiber "skins" take the loads along their length, in tension, with other layers taking the opposite and cross product loads (the layers are laid at multiple angles, usually 0-45-90-45-0 degrees.). The carbon fiber itself is usually designed to take multiples of what would be considered an infinite loading (>10 million cycles) but the adhesive gets cycled too, and that can have a far lower fatigue limit.
When that happens, there's something called "inter or intra-ply shear" that sort of tries to separate the plies by stretching and compressing the bonding adhesive.

On aircraft that use carbon fiber structures as primary structures, there’s usually a relatively short period before they have to be either x-rayed or ultrasonically checked for that interlaminar shear failures.

I'm not sure that that's being done with our current race car tubs.

Or maybe they’re just cutting back on things like that.

[JT265]

I think it means that "running over the curbs" means different things to different people.

Actually, I had a spirited discussion about the fatigue life of a racing tub with some guy that writes an occasional column for the rag, "Autoweek".

A honey comb structure, which is the primary construction of a modern race car comprises a sandwich construction of carbon fiber sheet skins on both sides of an aluminum or Kevlar honey comb core. The cars are designed to take expected bending and torsional loads for a reasonable lifetime, which is primarily considered its fatigue life (amount of times that the structure is cycled, either in bending or torsion).

Carbon fiber is a miracle material for strength and stiffness, but in almost all applications, its multiple layers, or plies, bonded together with an adhesive.

As the structure is flexed (which is being done not only by running around the track, but also by the vibration frequencies of the suspension inputs, the engine and gearbox, and anything else that can flex the structure.) the carbon fiber "skins" take the loads along their length, in tension, with other layers taking the opposite and cross product loads (the layers are laid at multiple angles, usually 0-45-90-45-0 degrees.). The carbon fiber itself is usually designed to take multiples of what would be considered an infinite loading (>10 million cycles) but the adhesive gets cycled too, and that can have a far lower fatigue limit.
When that happens, there's something called "inter or intra-ply shear" that sort of tries to separate the plies by stretching and compressing the bonding adhesive.

On aircraft that use carbon fiber structures as primary structures, there’s usually a relatively short period before they have to be either x-rayed or ultrasonically checked for that interlaminar shear failures.

I'm not sure that that's being done with our current race car tubs.

Or maybe they’re just cutting back on things like that.


The bigger teams are doing the ultrasonic deal Peter, although not as often.
Some of these tubs have long past the "best before" date though.

Man, you'd almost think you were a rocket scientist or something!!! ;)


:D