Sorry for another one of these posts, just after some advice on CAD and simulation software choices for a (very) amateur user.
I’m trying to design a mountain bike frame, I started this in Onshape, which I’ve found reasonably easy to pick up. So far I’ve got a fairly rough model, I want to do some strength analysis/simulations of it though. This would require a fair bit of work on it - there are bits where I was lazy with it and aren’t constructed properly, plus stuff that isn’t finished yet etc.
In terms of simulations, basically I want to see if it would snap/bend when subjected to likely peak forces and to cyclical loading. There’s an ISO standard and some other independent testing standards that detail various ways the frame should be fixed with loads applied at specific points with different magnitudes, frequencies and cycles etc, so I want to replicate these as far as possible.
Doing any kind of FEA/simulation in Onshape looks potentially expensive. Given I need to do a lot of work on my model I’m considering starting over in a different package. I’ve downloaded Fusion 360 for personal use but having to re-learn new software is off-putting, after a couple of hours messing around in it I’m finding it unintuitive, but plenty of people seem to like it.
I’m therefore after advice as to what the best approach is, I think my options are:
Continue with Onshape, in which case what would people suggest for strength simulations? A license for Onshape would give me access to its simulation toolbox but it’s $1500 for a year. I’ve had a look at Simscale but they don’t list prices which suggests its not cheap.
Use another CAD package. E.g. Fusion 360 is much more palatable at £510 for a year (currently on sale at £357). Is there anything else worth considering?
Pay someone to do it for me. I like this option, but I’m not sure how realistic it is.
Apart from recent experiences with Onshape, I’ve used Solidworks before for CAD and FEA but it was nearly 20 years ago on an undergraduate engineering course, so probably not that helpful. I work as an engineer doing mathematical modelling and simulation, but unfortunately not this kind; mechanical structures and material science have always been a bit of a weak point.
In terms of hardware I’ve got a laptop with 13th gen Core i7 processor, 32GB RAM and Nvidia 4060 GPU.
Take a look at Mecway. It is free for non-commercial use. It doesn’t have the fancy UI some of the products have, but the price is right, and it appears, for those with enough knowledge, that it is extremely powerful. For what you are doing it should be fairly simple and straight forward. https://www.mecway.com/
On the other end of the spectrum is Ansys. There is a free student version, with limitations on the number of nodes, among other things. It seems to be the industry standard, at least with the FE guru’s I’ve worked with. (MSC Nastran is also highly respected, and also has a student version. This is the solver used by NX.) https://www.ansys.com/academic/students
The downside to either of these solutions is that it isn’t linked with your modelling software. Make a change, export out of cad, import into FE, rebuild all the broken references. Lather, rinse, repeat a few dozen times, and the price tag for an integrated solution starts to make a little more sense.
Simscale does have a free option. Did it not run the types of analysis you wanted? We looked at it a few years ago and the pricing wasn’t bad for what they offered. They also had the ability to sell a lower plan than their standard one to us if we didn’t need as much analysis time. We didn’t end up getting the project that we had been looking at analysis software for, so didn’t purchase it.
Before you spend money on Onshape to get it’s simulation toolbox, make sure you can do the analysis you want.
Are you designing this for your own use or are you planning to sell the mountain bike frame you design? That will also change what things you can use. Once it’s for commercial use, you usually can’t use student or hobbyist versions.
Can’t speak to any other variants of the CAD connector, but the interface between SolidWorks and Ansys is incredible. Once you’ve got the hang of it you can reimport even major geometry changes and barely have to touch your fixtures / loading.
Thanks, will check it out.
I used Ansys briefly at university and found it incredibly un-user friendly, though one might hope things have improved since then.
I had looked at this a while back but dismissed it for reasons I can’t quite recall now. I think perhaps I was worried about hitting the usage cap with the free option, but if they can do custom pricing if I only need a little bit above the free option then it’s probably worth pursuing, thanks for pointing it out.
Well that is a can of worms…
Most likely titanium, though it isn’t my top choice. Steel would be preferable but I’m struggling to find anyone who’ll build it in steel. I’ve tried to parameterize tube diameters and wall thicknesses to be able to change this but I guess I might end up with two models if I keep insisting on putting the choice off as long as possible
EDF, the french Energy giant, is the main Sponsor of salome-meca and codeaster projects that offer a full fledged suit of simulation tools for free. they claim to use them to design their nuclear power facilities.
MarinoBike.com will do you a custom steel frame for an extremely reasonable price and come highly recommended. Depends how fancy your tube profiles get though.