Program request

[faksta]

Guys, I've been asked about some program which should be better to design a two-lever suspension (am I correct with term? ). Please, help anybody. Post here or just PM bbc - it's him who asked.
Thanks in advance.

[drakkie]

I've designed such a "double wishbone" suspension before, though it was a little flawed (understatement of the year) . If you need any help, let me know.

[faksta]

Originally Posted by drakkie

I've designed such a "double wishbone" suspension before, though it was a little flawed (understatement of the year) . If you need any help, let me know.

The situation is that bbc needs it, not me =)

[drakkie]

Originally Posted by faksta

The situation is that bbc needs it, not me =)

Relatively long PM can be found in his inbox.

[revetec]

I use SolidEdge but it costs. The package has a great 3D modeler which you can stress test. You then bring the first part into Assembly and you can make associated components off the initial part. You can also get it to operate on screen (even define gravity and spring tensions and loads. Unfortunately it's not by any means free. I use it extensively as I have 2 maintained seats.
Look at the SolidEdge banner on this link it is my design. And this image in the Siemens calender.

Quickly modeled suspension arm which took me no more than 10 minutes to model.

[Kozy]

I use Solidworks and have deisng this basic setup using it.

[revetec]

Is that your Revetec Engine in the back?

[Kozy]

It is indeed!

[jediali]

nice work kozy. I havent plowed in the technical accuracy (im sure you can pick holes) but heres my attempts at solidworks:
V10 idea:
VW engine modellling

[Kozy]

Both very impressive, that V10 is an amazing bit of work, I particulary like the exhaust manifolds. Care to divulge how you went about modelling those? The basic ones I have on my flat four were drawn using a 3d sketch and extruding a profile along it?

What do you do as a profession?

[jediali]

Originally Posted by Kozy

Both very impressive, that V10 is an amazing bit of work, I particulary like the exhaust manifolds. Care to divulge how you went about modelling those? The basic ones I have on my flat four were drawn using a 3d sketch and extruding a profile along it?

dont want to get too off topic but:

your on the right lines. multiple extrusions are based upon 2d sketches. by creating new planes each time you can change direction in steps. once you have got a rough setup you can then use the same 2d sketches to cut out the overlaps. its a bit experimental and im sure there is proabably a more automated routine (in a piping package maybe).

I made an inline 4 in proengineer in my 2nd year of uni, it was a popular package at the time. In that I made an exhaust manifold for a turbocharger and that kind of taught me that its actaully quite easy to make anything you want, given you have time and patience. The difference is that in proengineer I built up a library of parts (diferent angles and lengths of piping) and just put together a jigsaw of a manifold in an assembly, however in solidworks, each manifold is a single part made of many extrusions, by simply inverting it you can create a similar one for the other bank.

back on topic:

How did you calculate your suspension geometry? Did you account for anti dive and anti-squat. Also camber angles and such like? have you considered track change through suspension travel too?

You could even be adventurous and get into the dynamics of the vehicles. Setup a value for k (spring stiffness constant) and c (damping coeficient), perhaps even considering how they need to vary. look at NVH concepts and (un)acceptable frequencies

It all looks pretty good, spaceframe chassis too. If you just used projected extrusions to make that then kudos for your patience. There must be loads of hidden planes in that model. I havent got round to pretty back grounds for my models yet, i understand 3rd party programs are good for rendering solidworks models.

[Kozy]

Originally Posted by jediali

dont want to get too off topic but:

your on the right lines. multiple extrusions are based upon 2d sketches. by creating new planes each time you can change direction in steps. once you have got a rough setup you can then use the same 2d sketches to cut out the overlaps. its a bit experimental and im sure there is proabably a more automated routine (in a piping package maybe).

I made an inline 4 in proengineer in my 2nd year of uni, it was a popular package at the time. In that I made an exhaust manifold for a turbocharger and that kind of taught me that its actaully quite easy to make anything you want, given you have time and patience. The difference is that in proengineer I built up a library of parts (diferent angles and lengths of piping) and just put together a jigsaw of a manifold in an assembly, however in solidworks, each manifold is a single part made of many extrusions, by simply inverting it you can create a similar one for the other bank.

Mine was done in a far more basic fashion, I simply drew the manifold flanges on the top plane, then used a 3d sketch using splines to get the profiles I wanted for each of the pipes, then simply extruded along them. It worked, but it doesn't appear to be the right way of doing it as I can't cut the pipes where they join etc.

Originally Posted by jediali

back on topic:

How did you calculate your suspension geometry? Did you account for anti dive and anti-squat. Also camber angles and such like? have you considered track change through suspension travel too?

Anti dive and anti squat are generally regarded as a big no no in race car suspension design as they alter the castor angles under compression. It is generallt regarded to be better to have no anti dive and a constant castor angle so as to maintain stability under extreme braking. Camber angle haven't really been dealt with yet, I can adjust quite easily by altering the top ball joint locations on the uprights though.

Originally Posted by jediali

You could even be adventurous and get into the dynamics of the vehicles. Setup a value for k (spring stiffness constant) and c (damping coeficient), perhaps even considering how they need to vary. look at NVH concepts and (un)acceptable frequencies

Sorry what is NVH? I've heard of it before but can't place it. I could go into all that detail, maybe in the future I will, however the module in my course that the chassis is for, is more based around marketing etc, the solidworks only counts for a small proportion of the marks unfortunately.

Originally Posted by jediali

It all looks pretty good, spaceframe chassis too. If you just used projected extrusions to make that then kudos for your patience. There must be loads of hidden planes in that model. I havent got round to pretty back grounds for my models yet, i understand 3rd party programs are good for rendering solidworks models.

I used weldments and structural members on a 3d sketch, far easier!

My modelling techniques are essentially quite basic, I should look at impoving them in the future.

[jediali]

NVH=noise, vibration + harshness. The very basics look at frequencies that upset the driver and car most.

[revetec]

SolidEdge has 2D, 3D, Assembly, Simulation, Drafting, FEA, piping, wiring harnesses, frame design, motion, , as well as a calculation and modeling of such things as gears (which even tells you at what RPM they become audible), Bearings (including all data and loadings, which even gives you a bearing life), and a whole model catalog of just about every standard engineering part (such as bolts and washers, dowel pins etc) and you can also photo quality render within the program.

It's very extensive. It even has an extensive materials database with all the material properties, and shows centre of mass and volume.

I love it, there's nothing it can't do that I need.

[revetec]

Here is a few images of gear creation in Solid Edge, I just made a simple set of spur gears just to show the data available.
While the model isn't 100% accurate, you print off the data sheet and a gear manufacturer can make it exactly to the data. The model is made this way so you can accurately place it in your model and place a tangent on one gear face to the other. Really good for CAD assembly. Note the resonance speed of 12,543.6rpm (it really is that accurate)