How to start design a structural frame? and whitch CAD package is suit for beginer

[Ericyu]

Hello everyone,
I am a 21year old Chinese student, having a dream about cars since I was little. Last month I started a project, trying to design and make a space frame construction 2 seater car, The concept is similar to Ariel atom, but I don't want to copy it.
I have no experience of any CAD program before, so will you guys give me some point of how to design a structural frame? and which CAD package are more suit for beginers.
Your help are greatly appreciated.

Eric

[Ericyu]

Hello everyone,
I am a 21year old Chinese student, having a dream about cars since I was little. Last month I started a project, trying to design and make a space frame construction 2 seater car, The concept is similar to Ariel atom, but I don't want to copy it.
I have no experience of any CAD program before, so will you guys give me some point of how to design a structural frame? and which CAD package are more suit for beginers.
Your help are greatly appreciated.

Eric

[RiNaZ]

Eric, check with your engineering dept first whether they have some type of CAD program. If you want something for personal use and free, you can download Autocad Inventor from the autodesk website ...

http://students6.autodesk.com/

Another tip, you have a better chance of getting your question answered if you are very specific in what you want to know.

[Ericyu]

Thank you RiNaZ,
I am a student of Wyotech China, we don't have a engineering dept, and since the program has just been in China for few years, I don't have much resource to get from it.
I really want to have a team, but I didn't find people interested in it, now I have to do in myself, after the design process, my father can get me some help on the fabracation.
I have got a copy of solidworks 2008 and the 30 day trial version of Alibre design,
basiclly I want to know the method of designing a space frame,
how to make the 3d model on the computer.
some people say I can draw a 3d sketch in sw ,then apply tube feature to it, but i don't know how to apply the reature.
Thanks very much

[Ericyu]

Thanks every for your help, it's dinner timehttp://fsae.com/groupee_common/emoticons/icon_smile.gif I'll be back tomorrow.

[Austin]

At Sydney we design the suspension and come up with some pickup points for A-Arms, Pushrods, shock mounts, drive train etc. By this stage you should have well and truly chosen your engine and then you have the engine mounting points. Then it becomes a game of joint the dots. Ensure that you meet the current regs, particularly with roll hoops, front impact structure and percy!!!, we had issues in 06 with it and its a nightmare to sort out at the comp we also failed percy last year which cost us in design. Just beware that the chassis regs do change year to year and there are now new chassis templates from 09.

In terms of CAD, we use Solidworks, dig around in the help files and you will find a feature called Weldments. You can create a 3D sketch where you want the bars, I also like to have a separate 2D sketch for anything that is upright (roll hoops, bulkhead etc.) just makes life easier when trying to define the members and when building it. So I define 2 roll hoops, a front bulkhead in a 2D sketch and then use a 3D sketch to join the dots. Once you have that, you create a weldment profile, which is a cross section of the bar you want (it is a little tricky to save the profile but the help file explains it well). Then you just select the part of the sketch you want and you have a member. Easy!!!

As for FEA, I used to use strand as solidworks didnt handle frames very well, however SW 07 has beam elements but can only do straight bars, 08 can do curved members as well. We build a model (including suspension) then check the hub to hub rigidity. At one stage we didnt do that, we just applied a torque to the front pickup points, but it is way off so I dont recommend using that system. Then just aim for whatever number you are after.

Building one of these cars is a huge effort so I recommend you try to get some more help, but am very impressed you are having a go.

Good Luck

2008 USYD FSAE
Team Leader

[t21jj]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Austin:

In terms of CAD, we use Solidworks, dig around in the help files and you will find a feature called Weldments. You can create a 3D sketch where you want the bars, I also like to have a separate 2D sketch for anything that is upright (roll hoops, bulkhead etc.) just makes life easier when trying to define the members and when building it. So I define 2 roll hoops, a front bulkhead in a 2D sketch and then use a 3D sketch to join the dots. Once you have that, you create a weldment profile, which is a cross section of the bar you want (it is a little tricky to save the profile but the help file explains it well). Then you just select the part of the sketch you want and you have a member. Easy!!!

</div></BLOCKQUOTE>

That's just about exactly the same thing I did last fall. Solidworks weldment feature is a great time saver.

[Ericyu]

Thank guys, your help are ussful, I will try the weldment feature tonight as I return to my aparement, to make the car from dream to reality, I still got a lot to do and to learn, further help will bee needed from you http://fsae.com/groupee_common/emoticons/icon_smile.gif.
My plan is to finish the fabracation befor November, hope it will go well. I will give the update.

In China not many people do this kind of thing, make their onw track car, I really want to have some friends who are interested in cars, anyone here want to have a China friend? http://fsae.com/groupee_common/emoticons/icon_smile.gif

Eric