Designing a Spaceframe Chassis: What Forces Should You Consider?

[car_door]

I have about 60 12' lengths of 1.5" by 1.5" square steel tubing, and I would like to create a car chassis with it. The design I have come up with so far has a transverse rear mounted engine, and a central seating position with 3 seats behind the driver (1+3). I have posted some pictures of my design in the discussion thread I have linked to this post. Any advice with my project, improvements that could be made to my chassis design, or concerns regarding my design would be appreciated. http://hooniverse.com/2015/07/15/last-call-its-a-family-affair-edition/#disqus_thread

 

[berkeman]

I have about 60 12' lengths of 1.5" by 1.5" square steel tubing, and I would like to create a car chassis with it. The design I have come up with so far has a transverse rear mounted engine, and a central seating position with 3 seats behind the driver (1+3). I have posted some pictures of my design in the discussion thread I have linked to this post. Any advice with my project, improvements that could be made to my chassis design, or concerns regarding my design would be appreciated. http://hooniverse.com/2015/07/15/last-call-its-a-family-affair-edition/#disqus_thread

Welcome to the PF.

Your link takes me to a very strange and spammy place. Can you just upload your design to this PF thread instead please?

Also, 1.5" is way to thin for a vehicle frame -- are you going to weld several pieces together to make a full-size I-Beam section?

 

[pbuk]

I have about 60 12' lengths of 1.5" by 1.5" square steel tubing, and I would like to create a car chassis with it.

As said on the page you linked, you need a lot more triangulation. You might also need more tubing - this site has plans and a cuts list that uses 100'.

Also, 1.5" is way to thin for a vehicle frame -- are you going to weld several pieces together to make a full-size I-Beam section?

Then you would have an I-beam chassis not a spaceframe. 1" square 16 gauge is plenty.

 

[car_door]

New chassis pics.

 

[pbuk]

You need to ditch the roof, it will never be strong enough to provide any protection and uses too much tube.

 

[psycho rich]

Cadillac built a 4 liter v8 transverse mounted engine , I always thought that would make a great mid engine car .

 

[Nidum]

Start in a different place .

Estimate magnitude and direction of all forces acting on chassis when vehicle is moving . Many cases but choose a representative one .

Draw a space diagram of these forces .

Design space frame chassis of adequate strength to carry these forces .

There are usually some forces much larger than others . Start with these and as far as possible if a force acts on a line from A to B then design in frame piece(s) on same line A to B . Force is then carried directly and in a weight efficient manner .

Consider practicality of access for personel , assembly and maintenance .

The above is much simplified . In a real design for minimum weight many more things are taken into account .

For your purpose perhaps try doing some of the above on an intuitive basis - attempt to visualise the forces acting and then design a chassis to carry these forces effectively .