Doing Engineering Calculations From First Principles 2

[AlmostRetired]

Most of the questions in this forum seem to be about using engineering software, causing me to wonder whether students are actually taught to calculate things from first principles, which means they need to understand what they are doing, or are they just taught how to plug numbers into engineering programs? Any feedback would be instructive.

 

[IRstuff]

A valid question, but not answerable with the sampling of students here. It may just be someone scrawled the URL to this site in the CAD/FEA academy bathroom

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[BAretired]

I think the OP's question is valid across the board, not just the Student Engineer General Discussion. Those who cannot solve a problem by hand, should not be relying on a computer to generate the correct solution, because they won't be able to perform a sanity check. User instructions in software are frequently unclear or ambiguous. Users must be capable of determining whether or not the results are in the ballpark.


BA

 

[IRstuff]

My issue is that this site does not represent anything but the equivalent of 911; people are here asking questions only because they either didn't understand some part of their curriculum, or were lazy. This is not necessarily a reflection of either curriculum or quality of students overall.

Curriculum for EE looks fundamentally consistent with what I had 40 yrs ago, with some exceptions

https://ee.caltech.edu/academics/ugrad

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[271828]

Students are in school a long time. I teach five different structural engineering classes at our university. The vast majority of the time is spent on manual calcs. In one class, I spend 2-3 weeks showing them how to use a frame analysis program. In another, I have them verify manual results with the program. I don't show them "design" programs because they will learn otj.

I'm not sure what others do.

In my experience this is more of an issue with practitioners.

 

[EireChch]

I am actually trying to self teach myself some structural engineering basics, I have found a structural lecturer from Marshall University who uploads all his classes to Youtube (even before covid).

Every thing is thought from theory and first principles. I suspect all classes across the world are too..

 

[Daemon1]

Hello, from a student's perspective I'm gonna try answering this question. The answer is yes and know ; Yes because I actually know a fair amount of engineering concepts from first principle because they were taught by my lecturers and I understood them but there are some concepts who are still abstract to me and I don't know if I'll ever grasp that such as; a bunch of things in plate bending hypothesis where my lecturer just poured a bunch of differential equations without really explaining everything. So basically the answer is yes and no

 

[Daemon1]

@EireChch please can I get a link to the structural lecturer you mentioned ?

 

[rapt]

"knowing" it because it is taught in lectures is completely different to applying it in practice.

All engineers should have to do practical on the job calculation by hand until they have sufficient experience and understanding before they can design solely using computer software. Checking the hand calculations using software is a good way to start with software.

 

[EireChch]

@Daemon1 -

https://www.youtube.com/watch?v=y5mv7LB2eMo

here you go, a random video from one of his lectures.

 

[Daemon1]

I completely agree with what you say @rapt, practical ability associated to theoretical knowledge is the best combo !

 

[Daemon1]

Thanks for the link @EirChch

 

[desertfox]

I agree to many folk these days rely on software without really understanding the basics of the calculation they are doing. I always told up and combing engineers, to draw out by hand the problem where applicable in terms of a free body diagram this gives way to a better understanding of what’s happening. Very often I got told how much easier it was just to use the software, and my response was, well imagine you are on site somewhere in the middle of constructing some equipment and you have no access to computer software and someone asks you can you do a quick calculation on say a beam to see if it can be used in this instance, how would you do it if all you had was a pen/paper and a calculator.

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein

 

[271828]

Above, I mentioned that in my experience this is more of an issue with practitioners.

Practitioners tend to be under severe time pressure. Frequently, they must check something outside their area of expertise. Being human, if there's a program in the office that "will do the design" then they'll typically use it and move on.

Recently I peer reviewed on a project. The PE made design decisions based on what "the program would design." If a scheme was outside the scope of the program, then that option was out. Also, over the course of the project, I asked multiple times about the limit states being checked. In not even one instance could the PE explain what the program was doing. That was an extreme example, obviously.

 

[IRstuff]

many folk these days rely on software without really understanding the basics of the calculation they are doing.

I think it's presumptuous to assume that only this generation is afflicted with that disease; we had the exact same discussion 40 years ago, when CAD was still in its nascence. GIGO is NOT a new term ;-)

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[Pud]

Anybody remember slide rules?

I still mentally do a check on what an answer should be around. Mainly using CAD to tell what a part volume is. (Or is not!).


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[desertfox]

I remember slide rules and just previous log tables lol.

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein

 

[Settingsun]

imagine you are on site somewhere in the middle of constructing some equipment and you have no access to computer software and someone asks you can you do a quick calculation on say a beam to see if it can be used in this instance, how would you do it if all you had was a pen/paper and a calculator

Alarms going off. Best to tell them you'll get back to them with the answer. The calc may be basic but why has the plan gone awry? Good for everyone to take a breath.