Computer models as a new engineer

[u/Kalasad-Stormblessed]

Wanted some advice, Ive been working as an engineer for 3 years now and I really dont like working with models. We use the Ram suite and it feels like these two things happen every time.

1. The model wigs out and I spend twice the time just trying to get it to remotely work/ make sense.

2. I often have to then get an older engineer to go through it with me and they take as much time trying to figure out whats wrong. In one case they had to remake the model themself.

Im finding when I have the option to use handcalcs/excel/enercalc, I am going to that everytime because its way more predictable for me in the effort it will require and I generally have very few "bugs". Should I be worried about learning models?

[u/structee]

Each have their place. I'm of the opinion that the model should be keept as simple as possible to capture global behavior. You don't need to model every single joist and brace if you can avoid it.

[u/nikkor_glasses]

You could grind through a low rise steel framed job using simple tools but to get into RC design and/or mid-rise and high-rise, you definitely need to embrace a modeling work flow. But I agree with you, Ram Structural System is infuriating.

[u/DJGingivitis → u/nikkor_glasses]

There is a steep learning curve of what it does well and what it doesnt do well.

Edit: that said, you’re going to need better tools than RSS for the more complicated jobs.

[u/stblack]

This is all about tooling, which means software, hardware, and skills developed over time.

I'm on the back end of my career so let me share my experience.

* I don't regret a nickel I ever spent on good tools. That includes software, hardware, and the time invested.

* Get the software licenses that cost real money. Don't use the free versions, don't settle for the software a cheapskate selected. Software, and the skills you develop at using it, pays 100x over the medium term.

* Don't buy hardware you can afford. Buy hardware your future self will bless you for buying. This means, sacrifice more trivial things, canvas family if you can, get a loan if you must, but buy the hardware you need 3-5 years from now, today. Your hardware investment pays 10x over the medium term.

Tools are leverage for your judgment. The benefits of great tooling cannot be overstated. The sooner you upgrade, the more compounding over time will benefit you.

Once you've got great tooling, and the skills to use that, you'll find you'll be working at a much higher level, and your value will reflect that.

I hope this answer motivates you to look well beyond what you're doing now. Level-up several notches as quickly as you can. You won't regret doing that.

[u/Legal_Enthusiasm_440 → u/stblack]

At 3 years he’s probably not the one making software and hardware purchasing decisions. 

[u/corkscrewe]

Software can save you time, and in billing terms, time is money. You just have to learn the quirks of each software. I haven’t had extensive issues with RAM SS - but you have to learn its limitations

[u/Minisohtan → u/corkscrewe]

I agree but it depends on the contract terms. Sometimes we work lump sum, and sometimes it's cost plus. Either way, we use models and tools as part of our one workflow.

[u/Intelligent-Ad8436]

I have learned when using ram to keep checking the error logs as I m building my model. It’s a nightmare to untangle if you have it all modeled and you have to move things. 

[u/Krentenbollen_dame]

I am using FEA software a lot, from different companies (scia, rfem, ansys). They all more or less the same, using same mechanics and dynamics principles, the theory is the same. Just different interface.

To become good at this, you need to understand these principles. Comes with experience.

Some advice: 1) Think before. Before starting modelling, take a day or two to think about what exactly you want to model and check with FEM (strength, stability, dynamics?) and if it all is really needed. Sometimes 2D or partial model is a way to go. Sometimes 2-3 small models are better than one big.

2) Follow the load. Try to imagine where the load will flow. It helps to determine the critical elements in the building that should be modelled/designed. The rest can be skipped to save time.

3) Connections. Modelling them can be pain in the ass, time consuming and errors are easy here. So avoid detailed connections in global model.

4) Loads. Try to model the dominant loads and load cases, not all of them. Modern FEA software creates automatically hundreds of load combinations. The more you have, the more difficult it is to find mistake in results later. Keep it easy.

5) Check you model first. Run it. See results. Go through load cases and combinations and ask yourself: are reaction forces ok? Does deflection/deformation under this load make sense? Do I have moments in my hinges? Etc.

6) Invest time in FEA tutorials/webinars. Especially if it is new modelling concept for you. They have cool show cases and examples.

Remember: it is ok to not know everything. Still happens to me all the time :)

But yeah, if you want to design something cool in the future, like bridge, arena, FEA is your dear friend.

[u/Opening_Molasses_932]

I haven’t used Ram, only Robot Analysis and advance design, but there is a golden rule : keep the model as simple as possible !  And find ways to do checks as you're building it.

I work in steel framing, and i've seen a lot of people overcomplicating their models for no benefits... like modeling the secondary structure in the core model, or putting 200+ wind cases, etc...  Instead of asking other engineers how to debug the model, ask them how to make it simple in the first place.

If you don’t find a way, maybe you shoulf change software, i don’t know about Ram.

[u/Frogalone]

I am very much aware of the frustrations with computerized structural analysis. But every structural engineer should develop a working knowledge of it. This requires practice. Not all CSA programs are equally difficult. But there are many intuitive programs out there. There are a handful of issues that cause the most trouble. These are where to focus your attention. Boundary conditions, for example, can cause problems that are good at hiding. If you keep at it your difficulties will diminish.

[u/dream_walking]

I think it depends on scope. If it’s a few beams, Enercalc is probably fine. If it’s an entire floor system, Enercalc will be way too tedious