Came across industrial casting simulation software, has anyone ever used these?

[u/Loud_Campaign5593]

How are solvers for these simulations even developed? Has anyone here ever used them? This is one is Magmasoft for reference

[u/bionicdna]

I build similar ones professionally, but for molten plastic. At the end of the day it's just all some variant or simplification of mass, momentum, and energy equations. The more one can delete from the equations, the faster and simpler they are to run, at the cost of accuracy. There are lots of different numerical techniques used for solving the PDEs but common setups involve either some finite volume or finite element formulation. Plastics and metals solidifying are most tricky in the phase change where you have to figure out how to accurately model crystallization.

[u/AsyncVibes → u/bionicdna]

This is a great explanation! thanks. That tradeoff is basically how I'd define generalization, you delete enough from the model that it stops being exact for any one case and starts covering a wider band of them. Same curve I keep running into: accuracy per variant drops, number of variants it survives goes up. The crystallization problem is interesting to me for the same reason. Phase change is where the simplification stops being safe, right? Curious how you decide where that line is.

[u/bionicdna → u/AsyncVibes]

I like to use different modeling techniques for different jobs. If you're trying to just consider fill, and the fill transient is fast enough, you might be able to get away with ignoring a lot of the fancy heat transfer and thermo as well as phase change, and then use that simulation's result as an initial condition for a different simulation that is maybe simpler on flow physics but includes the thermophysics. Complex math is hard to reason about and validate, so I really like to keep things as dumb as possible because it not only allows them to solve more quickly but they're easier to debug and reason about. The line for me is really "is this tool solving my objective", so that's what drives my decision on what the minimum set of physics I can capture is and where to make the simplifications.

Crystallization is hard and truthfully I'm not all that educated on it.

[u/Loud_Campaign5593 → u/bionicdna]

thanks for sharing your experience, this is the type of comment i really like! very interesting indeed

[u/stoputa → u/bionicdna]

Aren't all FEM PDE solvers specific to the equation since the weak form needs to be manually derived (iirc FDM can be made generic)?

I'm curious why a generic Navier-Stokes solver wouldn't work here but I guess the reason is stated in your last sentence. But then again if you need to account for state changes, it sounds really hard to formulate it for a FEM solver

[u/bionicdna → u/stoputa]

General forms can work, they're just typically harder to solve because they include so much physics haha. Not all of the terms are needed. Also personally I prefer FVM just because my mind can reason about the math with fluxes more easily than FEM. I've had much more education in FEM CFD methods and they all feel so complicated to me.

[u/Lanfeix]

Programming the Finite Element Method (Third Edition) by I.M. Smith and D.V. Griffiths. Its in Fortan 90. that what I learned 20 years ago. I didnt do every much of it but its what my boss use to do. most people just use ansys or another big simulation package these days

[u/Loud_Campaign5593 → u/Lanfeix]

Super interesting. never even heard of fortran 90 so intriguing for sure

[u/Lulzd0zer]

MagmaSoft is i would say the golden standard casting simulation tool. The complexity does not lie in how flow is solved but the material models that govern liquid and solidification behavior for the temperature ranges. There are many others NovaCast for instance. It's a combination of looking at the flow / heat / solid mechanics and material behavior, very potent!

[u/Loud_Campaign5593 → u/Lulzd0zer]

That sounds interesting. Where do you gather the information for these material models to be made, as in, how do you know which source of information to use to model it after? Is it research papers or some standardized institution?

[u/Lulzd0zer → u/Loud_Campaign5593]

Both the companies and researchers generate this material data, by companies I mean like MagmaSoft that also makes the software. There are also vast amount of research going into adjacent areas such as computational thermodynamics that can be incorporated in such simulation softwares. Check out ThermoCalc a well know software for pure material thermodynamics.

[u/rarlei]

I thought this was a toilet filling with lava

[u/CaptCuke → u/rarlei]

Usually happens after taco bell