The list: Torsional Rigidity - Page 3

SDNR · 03-21-2007, 06:15 AM

Quote:

Originally Posted by Mr. Mercedes

Rob...its quite simple really. Torsional rigidity is defined as:

Get it now?

From my rudimentary understanding though, the more rigid a chassis is the less chassis flex exists thus better withstanding the stresses caused by the drivetrain and other forces acting on the vehicle (road bumps etc.). It also provides a better foundation for absolutely precise suspension tuning.

Or maybe I'm talking rubbish.

Thanks for this Mr. Einstein.

BTW, aren't aluminum bodies generally stiffer than steel ones?

Also, has anybody got the figures for the Rolls-Royce Phantom DHC?

Mr. Mercedes · 03-21-2007, 06:20 AM

Quote:

Originally Posted by Rob

Thanks for this Mr. Einstein.

BTW, aren't aluminum bodies generally stiffer than steel ones?

Also, has anybody got the figures for the Rolls-Royce Phantom DHC?

lol...I think I may be talking rubbish, but that's my inferred understanding about the subject. Could somone who really knows what they're on about please explain? Google isn't much help.

I also thought aluminium would be stiffer than steel, which is why im quite perplexed about the A8 vs. Phaeton.

Mr. M · 03-21-2007, 06:20 AM

Quote:

Originally Posted by Rob

BTW, aren't aluminum bodies generally stiffer than steel ones?

Also, has anybody got the figures for the Rolls-Royce Phantom DHC?

I thought so too, can someone explain the metal characteristics?

I'll try finding the DHC numbers... But since it's a new car, it's quite difficult.

Just_me · 03-21-2007, 06:21 AM

Quote:

Originally Posted by Rob

Also, has anybody got the figures for the Rolls-Royce Phantom DHC?

I searched for it but no numbers, the pressrelese from RR just say almost as rigid as ....

Mr. Mercedes · 03-21-2007, 06:25 AM

ok heres what I found on google:

torsional rigidity

A vehicle body’s resistance to twisting forces

In the world of physics, just about any word beginning with “tor” has something to do with twisting — such as torque, which refers to the twisting force exerted by an engine. Torsion itself simply means twisting, and in a vehicle, it refers to the kind that would happen if Godzilla grabbed it, front and rear, and twisted either end in opposite directions. The forces a vehicle encounters when cruising and turning are not quite as great, but they are a significant issue. A vehicle with high torsional rigidity resists these forces better than one with low torsional rigidity.

A little flex in a vehicle’s structure doesn’t hurt, but overall, you don’t want too much torsion in your vehicle’s body. Low rigidity in a vehicle results in vibrations and degrades handling performance. Good handling performance relies, in part, on suspension designs that optimize wheel/road contact under all conditions. Introduce too much torsion to a vehicle’s body, and the wheels are no longer where they are supposed to be relative to each other. In these cases, even well-engineered suspensions don’t stand a chance.

So there is such a thing as too much rigidity.

More:

Sometimes called chassis stiffness. It relates to how rigid the chassis is in twisting. Imagine a sport utility vehicle that needs to climb over rocks. Those without long suspension movements sometimes have lower torsional rigidity to allow the chassis to respond to uneven ground. A passenger car, on the other hand, should have high torsional rigidity in order to give the car a smooth ride, less vibration and better handling. Sports and performance cars are usually the stiffest in order to minimize any flex except for that offered by the springs and shocks to obtain consistent handling.

Just_me · 03-21-2007, 06:31 AM

Porsche Carrera GT - 26,000Nm/degree

Ultimate Car Guy · 03-21-2007, 06:41 AM

I can't believe BMW has comparatively low rigidity, i thought they'd have amongst the highest, thats why their cars handle so well.

Just_me · 03-21-2007, 07:01 AM

Saab 9-3 Sportcombi - 21,000 Nm/degree
Opel Astra - 12,000 Nm/degree
Bugatti EB110 - 19,000 Nm/degree
VW Passat (2006) - 32,400 Nm/degree
Land rover Freelander 2 - 28,000 Nm/degree
RR Phantom - 40,500 Nm/degree
Mazda RX8 - 30,000 Nm/degree
BMW X5 (2004) - 23,100 Nm/degree

SDNR · 03-21-2007, 07:14 AM

The Phantom's rigidity is very impressive. 40,500 Nm/degree makes it one of the most rigid cars made.

monster · 03-21-2007, 08:32 AM

Quote:

Originally Posted by Mirage77

I thought so too, can someone explain the metal characteristics?

.

Aluminium by itself is not stiffer than steel, you can have aluminium alloy with different elements to make it stiffer, steel is generally stiffer than aluminium. That is pretty much all i remember from 1st year uni material science.

I am impressed by the RX-8, it is lacking a B pillar but those Mazda engineers have managed to design a very stiff body.

03-21-2007, 06:25 AM	#25
Mr. Mercedes Fanatic Join Date: Oct 2005 Location: Australia Posts: 1,391 Thanks: 154 Thanked 105 Times in 75 Posts	Re: The list: Torsional Rigidity ok heres what I found on google: torsional rigidity A vehicle body’s resistance to twisting forces In the world of physics, just about any word beginning with “tor” has something to do with twisting — such as torque, which refers to the twisting force exerted by an engine. Torsion itself simply means twisting, and in a vehicle, it refers to the kind that would happen if Godzilla grabbed it, front and rear, and twisted either end in opposite directions. The forces a vehicle encounters when cruising and turning are not quite as great, but they are a significant issue. A vehicle with high torsional rigidity resists these forces better than one with low torsional rigidity. A little flex in a vehicle’s structure doesn’t hurt, but overall, you don’t want too much torsion in your vehicle’s body. Low rigidity in a vehicle results in vibrations and degrades handling performance. Good handling performance relies, in part, on suspension designs that optimize wheel/road contact under all conditions. Introduce too much torsion to a vehicle’s body, and the wheels are no longer where they are supposed to be relative to each other. In these cases, even well-engineered suspensions don’t stand a chance. So there is such a thing as too much rigidity. More: Sometimes called chassis stiffness. It relates to how rigid the chassis is in twisting. Imagine a sport utility vehicle that needs to climb over rocks. Those without long suspension movements sometimes have lower torsional rigidity to allow the chassis to respond to uneven ground. A passenger car, on the other hand, should have high torsional rigidity in order to give the car a smooth ride, less vibration and better handling. Sports and performance cars are usually the stiffest in order to minimize any flex except for that offered by the springs and shocks to obtain consistent handling.

03-21-2007, 06:31 AM	#26
Just_me Executive Join Date: Sep 2005 Location: Sweden Posts: 15,487 Thanks: 1,062 Thanked 3,722 Times in 1,583 Posts	Re: The list: Torsional Rigidity Porsche Carrera GT - 26,000Nm/degree

03-21-2007, 06:41 AM	#27
Ultimate Car Guy Enthusiast Join Date: Oct 2006 Posts: 223 Thanks: 22 Thanked 25 Times in 19 Posts	Re: The list: Torsional Rigidity I can't believe BMW has comparatively low rigidity, i thought they'd have amongst the highest, thats why their cars handle so well.

03-21-2007, 07:01 AM	#28
Just_me Executive Join Date: Sep 2005 Location: Sweden Posts: 15,487 Thanks: 1,062 Thanked 3,722 Times in 1,583 Posts	Re: The list: Torsional Rigidity Saab 9-3 Sportcombi - 21,000 Nm/degree Opel Astra - 12,000 Nm/degree Bugatti EB110 - 19,000 Nm/degree VW Passat (2006) - 32,400 Nm/degree Land rover Freelander 2 - 28,000 Nm/degree RR Phantom - 40,500 Nm/degree Mazda RX8 - 30,000 Nm/degree BMW X5 (2004) - 23,100 Nm/degree

03-21-2007, 07:14 AM	#29
SDNR Connoisseur Join Date: Sep 2005 Posts: 5,985 Thanks: 1,319 Thanked 870 Times in 534 Posts	Re: The list: Torsional Rigidity The Phantom's rigidity is very impressive. 40,500 Nm/degree makes it one of the most rigid cars made.

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