Coil sping design and movements

[liftedzj]

I do a bunch of off-road truck and rally car design and am currently working on a front suspension design which is a little complicated. I would like to model as much as a can before I pull out the welder. The problem is I need to simulate coil springs and rubber bushings. Now I have NEVER done anything like this before and am hoping that someone can shed a little light on the fesibility of doing this before I spend all sorts of time and frustrate myself.

Beyond that I have been following the ball-screw thread and have a similar request. What I need is basically a barber-pole type model. Imagine a long round shaft with a spiral pattern wrapping around. Now imagine that the spiral is all the way to the centre axis using and endmill. Kind of like an acme thread but with a really REALLY long travel.

Any thoughts? TIA

Crash

[DareBee]

The simplest way to model is just make cylinders the correct diameter and drop them in as space holders. You could make a couple of configurations to similate different ride heights.
If you want to model the spring; it can be done with a simple helical sweep.
If you are asking if you can make your actual model of the spring real time compressable, I would have to say no; unless 2005 allows this but I havent installed that version yet.
I dont quite understand EXACTLY what you have asked for but hope this helps. Be direct and specific with your questions.

[liftedzj]

Yeah, I guess I should have been a bit more clear with the actual question. I am trying to model the actual range of motion of a coil spring and a rubber bushing to see how things flex. I have all the parts assembled but I can't move things to represent motion.

[DareBee]

If you want to have material "flex" in design software you will need to spend at least $100000 probably more to get something to Sim that.
As I said, With different configurations you can show in different positions but flex is out of the question.

[scottsss]

For the springs you can calculate the range of motion. Then threw configs you could have the two or more configs showing the the differnt range of motion. This the computer would not calculate, you would. As for your question of getting Solidworks to do this....I am not aware of it being able to do this at this time. Their might be a plug in or third party piece you can add in. But as it stands, it does not understand the differnce in material.

Note if I am wrong on and issue or two I'm happy if you point it out, I'm still learning this great piece of software.

[jphagen]

Go find the program called working model.
It will allow you to simulate all the forces and ranges of motion of the
system based on your imput..
Comes with some nice demo's.

[DDM]

Well you could in a way farmer job it and build adjustability into the system. Go ahead and draw up the basics. When you draw up your shock/spring mounting set up multiple mounting spots. This might be advisable when working with an A arm setup with Coilover shocks. I'd be happy to help you out if I knew kinda what you were working out.

Carl

[Lotus14]

Actually you should go to the SolidWorks web site, spring motion has been done before. You might look at some of the samples to see if it is still there, or check with some of the other SolidWorks users sites for files of samples which you can copy, and modify.

I used a moving coil spring from one of the sites in SW2001, so it can be done. What you need is the animation stuff. I did it for a check valve; the motion of a car over terrain is a little more complicated.

I'm not sure you can model changes in the bushings. You might be able to model the torsion, but if you want to model side loads, and offsets that occur, that might take quite a bit of math. Contact someone like Lord who makes bushing, and engine mounts for aircraft engines, and see if they have anything already done. I've found that many companies, even big ones, have info like that available...after all their in the business to sell the bushings, and they are going to try and help you.

My last thought, as goofy as it may sound is; if you are near any large college check to see if they use SW. I had a kid from the Stanford Engineering School do some work for me, and this guy knew the program so well he would send e-mails to SW telling them to rewrite their code. He modeled a human coln for a medical device, and had the device moving through the coln, and doing all sorts of stuff.

Hope a little of this helps.

[scottsss]

I've yet to play with animation. But if what you say is true and the software can do the stretching then it should be able to do the compresions since one is the inverse of the other. I'll poke around and see if I can find a model or example some were. Be cool to know.

I'm taking the second of three classes at my school offered in SW. They do not cover alot of what the program can do. Sham each time I find something on my own I am more and more impresed by SolidWorks.

[DareBee]

SolidWorks will not actually stretch or compress the part.
Your key word was ANIMATION, just like cartoons the part is modelled 100s of times and put together to make animated frames. It is not actually reacting with the push pull of other components.

[Aley]

It's not real-time, but you could potentially use an equation to drive the length of the helix you use for your sweep when you model the spring. You could then move the suspension parts through their range by moving them in the assembly; you can select which parts Solidworks will pay attention to when you move things using physical dynamics, so you would select your suspension parts but not the spring. When you move the suspension the spring won't change length, but after you've moved the suspension and rebuild your spring will resize itself to fit the new space.

Of course, this won't help you if you want to really model the behavior of the spring in a typical automotive suspension since the spring perches don't stay parallel. AFAIK there's no way to bend a helix such that it simulates a spring being compressed between two non-parallel plates. If you just want to check for coil bind or gross interference between parts, though, it might get you close enough.

I haven't actually done it, although I've kicked around the idea for some of my designs that use compression springs. As far as that goes I don't remember how to use equations in Solidworks, since it's something that I've never had a need for. It was covered in a class I took, but that was a long time ago.