Chassis rigidity

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Metal is rigid. That's why it's good for makin' stuff. Unless your rockers rot out, a unibody car isn't gonna really lose rigidity.
 
Originally Posted By: Ethan1
Metal is rigid. That's why it's good for makin' stuff. Unless your rockers rot out, a unibody car isn't gonna really lose rigidity.


Depends on the car. Jack up the front corner of an olds ciera and the rear doors will scrape, hang a bit when opening or closing them.
 
I had a 1990 Ford escort that the doors ranged when making curves at a more unleveled planes of pavement. I could hear the upholstered whine.
 
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My car three-wheels onto my driveway.
Chassis bracing is heavenly
smile.gif
 
Originally Posted By: spasm3
Originally Posted By: Ethan1
Metal is rigid. That's why it's good for makin' stuff. Unless your rockers rot out, a unibody car isn't gonna really lose rigidity.


Depends on the car. Jack up the front corner of an olds ciera and the rear doors will scrape, hang a bit when opening or closing them.


A 1993 Ciera wasn't rigid from the factory
 
Originally Posted By: Ethan1
Originally Posted By: spasm3
Originally Posted By: Ethan1
Metal is rigid. That's why it's good for makin' stuff. Unless your rockers rot out, a unibody car isn't gonna really lose rigidity.


Depends on the car. Jack up the front corner of an olds ciera and the rear doors will scrape, hang a bit when opening or closing them.


A 1993 Ciera wasn't rigid from the factory


Thats my point. Its metal , its a unibody, it ain't rusted and it ain't rigid.
 
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When steel was starting to be used, people thought that it was in fact perfectly rigid...And they built bridges and trains and all sorts of stuff with it based on that assumption.

Turns out that if they were right, everything would have broken, as individual members overloaded instead of load shared.

As it turns out, steel is elastic, and changes dimension under applied load...if it gets loaded enough, it becomes plastic, and yields.

Look at the Eiffel Tower, all of the steel in that structure has undergone a process of elastic and plastic deformation and is fairly equally load sharing.
 
Originally Posted By: Shannow
Look at the Eiffel Tower, all of the steel in that structure has undergone a process of elastic and plastic deformation and is fairly equally load sharing.


The Eiffel Tower is made of steel?
 
Sorry, if the wrought iron of the Eiffel Tower behaved the way that they believed at the time (i.e. was "rigid") i would have collapsed. Elastic and Plastic deformation spreads the load over the members.
 
Originally Posted By: Shannow
Sorry, if the wrought iron of the Eiffel Tower behaved the way that they believed at the time (i.e. was "rigid") i would have collapsed. Elastic and Plastic deformation spreads the load over the members.


You read/studied an article that shows they thought something different about the iron used to build the tower? I'd like to read it if you have a link. I figured they knew pretty well how that iron behaved.
 
No, it was just that in the early days of steel (iron), they designed on the assumption that the material was infinitely rigid, and that joints were installed such that loads were all shared equally.

Well joints couldn't be installed "pre-tensioned" so to speak, and there's no way that rivet and bolt holes were going to be installed accurately to tenths of mm, so their entire design process was wrong.

Back in the day they were saved by the fact that steel is elastic, and will share load, and then has a yield followed by plastic deformation, so the overstressed members could yield slightly, and allow adjacent members to pick up the load.

Their original belief would have lead to catastrophic failure, and they were saved by the material properties that they later learned about.

Saw this to great effect when I built the 330 foot diameter "Jupiter 2" in the foreground in the late 90s...a self supporting dome, that started with a large fabricated central disk atop a massive scaffold, and we had to install the legs spoke by spoke (while still having the earthworks on one side open)...as the legs loaded up and relaxed, the risk of crushing the scaffold had to be matched by getting the new members in as the structure came ever so slightly earthward every beam.

flat,1000x1000,075,f.jpg
 
I would be more concerned about the suspension, not the rigidity. I don't think a car should do that at such low speed.
 
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