BIW design 1

[sj2000]

Hi there,

I recently joined this forum. I have couple of questions related to BIW,

1. What is the exact workflow for designing car BIW parts? (can I find reference parts online, closely matching real life parts)
2. What is the best approach to design BIW parts, from available parasolid / IGES file.

Regards,

sj2000

 

[GregLocock]

I imagine if you can define an exact workflow then you will be replaced by a computer pretty quickly.



Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[sj2000]

Hi

I appreciate the fact.
However I am keen on understanding the workflow that car industry in general follows.
Can you elaborate please. I am new in this area, though have experience working with CAD for years.

Regards,

sj2000

 

[GregLocock]

Not me, never done body CAD in my life.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[BrianPetersen]

This is a very generic question that can only be answered in a very generic manner.

Styling, aerodynamics, project management, powertrain, marketing, etc come up with an outside shape that is sufficient to fit whatever needs to be put inside, meets the aerodynamic requirements, satisfies the stylists, etc.

Then body engineering designs all the inner structure bits that are necessary to meet crash requirements, meet NVH requirements, comply with all the applicable standards in the entire universe in which the car will be sold (not easy), allow the doors to open and close properly, not trap water in places that will cause premature rust, be constructed out of sheet metal parts that can actually be built (not easy), and in many cases fit the bodyshell over an existing "platform" that defines where many of the components have to be and in many cases defines what those components are and how they attach. Then manufacturing gets involved and the design changes from what it would be nice to build, to what can actually be built.

The process is iterative. It repeats many times in finer and finer detail. It backtracks once in a while when someone discovers an "oops". And there will be "oopses". Lots of them. Some early in the process, some late in the game when something happens that no one foresaw. Some of them after production start.

I only see it when it gets to the robots and the tooling that are involved in sticking all the bits and pieces together. (usually welding, not always) An "oops" at this stage changes robots and fixtures ... and it has happened, Many times.

 

[dcheck]

I wander that whether BIW use checking fixtures.I used to use a fixture from a company Watton,but we use their fixtures for stamping parts.

 

[BrianPetersen]

Your sentence is not clear. Plenty of check fixtures are used - especially during commissioning (of a new model, of new tooling for an existing model, of new production equipment for a new model or an existing model, etc).

Once the equipment starts running, the check fixture isn't normally used unless something goes wrong in the process.

 

[sj2000]

Hi Again,

I have been searching myself for the precise steps in the BIW design process.
But still not sure how the BIW surfaces are derived exactly.

I agree this is an iterative process in any design, but need to understand the basics of how to start the design of BIW from scratch.
How the individual part is designed/arrived at?

Please share your thoughts.

Regards,

s_j2000

 

[leafjerky_imported]

Hi sj2000,

Look at this post (

http://www.eng-tips.com/faqs.cfm?fid=781).

You can find a copy of the first book (Motor Vehicle Structures) here (

http://en.bookfi.net/md5/FD85C22586AD1E539CF019324F68EBCE).

I hope that helps you some. Good luck!

Regards,
David

 

[mlevett3]

I'd also recommend Automobile Body Structure Design by Malen. Covers much of the same "simple structural surface" technique as Brown, but also touches on some more crashworthiness and vibration considerations.