Engineering knowledge loss?? 2

[40818]

Hi all, just a quick ponder...
What is the general consensus regarding the loss of classical engineering knowledge due to the ever increasing reliance on "black box technology". I believe that these very useful tools are exactly that, tools, which should be used by a stressman or designer to aid and quicken their work. Examples of the loss for designers is due to the use of better 3D modelling programs such as catia, a designer no longer has to give sufficient information on a 2D paper drawing to make the part (a big bugbear of mine being a stressman and ex designer long ago).Another example is that Airbus have a black box program to calculate a bolt group analysis,yes a bolt group analysis. Progress with technology is one thing, but are we eroding basic knowledge by automating processes and not allowing new engineers to understand principles and underlying theories behind analysis. Then there is always the FE debate...

 

[MikeHalloran]

Some of the questions, and answers, here, suggest that your assertion is correct.



Mike Halloran
Pembroke Pines, FL, USA

 

[IRstuff]

But, there's no alternative.

Trying to do things by hand for the current level of performance would require substantial abstraction, to the point where you'd have to over design by so much that it wouldn't even be practical.

TTFN

FAQ731-376

 

[Kwan]

I'm working on a program where we are developing loads (external and internal). We don't use the fancy cfd and fem programs. Why???? Because they take forever! I've seen a comparison with our loads and loads from cfd/fem. They are quite similar, however our method produces results quite efficiently.

Excel is awesome for the external loads. Then unit beam method for internal loads.

 

[tbuelna]

40818,

You sound like a "veteran" engineer that has found it difficult to keep abreast of current engineering tools. A CAD or FEA application is no better than the person inputing the data and intepreting the results. The CAD/FEA programs are tools just like calculators, drafting machines or slide rules. I'm a mechanical designer and I started out on the drawing board, but I have been using CATIA for the past 12 years and it has improved my productivity 3 or 4 fold. As for putting things on paper, don't your analysts submit stress reports?

Your gripe about Airbus and their use of an automated program to perform such mundane tasks as simple fastener loads, is off base. Airbus likely has a very sound reason for doing this: It guarantees that every analysis is performed the same, regardless of who did it. It's part of the standardized methods and processes encouraged by quality systems like AS9100. I don't agree with everything that standards like AS9100 require, but in this case it seems very logical.

Your designers and analysts should be getting their training BEFORE they are asked to perform their particular function. Or they should under the watchful eye of someone more experienced. So engineers not understanding their tasks is a management issue, not a technology issue.

I must be honest however. Even though I do the bulk of my work in CATIA V5, I still do my initial layout work in a simple 2D CAD system (AutoCAD), since I find it hard (as well as time consuming) to conceptualize things in a parametric, solid modelling environment.

I appreciate your comments.

 

[IRstuff]

The other thing to consider is that we've already given up other black box things.

Even the simplest calculator can do logarithms and transcendental functions. Would you advocate doing sines by Taylor series expansions, or using a table lookup?

Do you want to chop your own wood and build your own cooking fires?

Would you trust your bank's calculation of your balance if your account was maintained by some poor schmuck cranking away with an adding machine?

Every generation makes progress based on the previous generation's progress. Otherwise, we'd still be driving around in horse-drawn buggies. How many of the latest cars can you perform a tuneup on?

TTFN

FAQ731-376

 

[40818]

I'm by no means a veteran engineer, been in th business about 12 years or so. And i do use catia and nastran/patran. But my point is more of the loss of engineering knowledge by using said tools to accomplish tasks. For example, a beam on 3 supports being solely solved using FE rather than tradition methods. The use of tradition methods develops an understanding of whats going on which needs to be captured before simply using FE to give answers. I stated airbus' approach with regard to a bolt group as an example of the trend, not a critisism of their idealogy. My point in question was that people are now using said tools with never having done a simple bolt group. I'm all for progress and development, but we cant loose track of underlying knowledge in the progression.

 

[israelkk]

I would like to add to 40818 that the situation came to a point where in professional meetings and discussions no longer one can give straight answers and estimats because they have no "feeling or physical understanding" or simple tools to evaluate cases within +/- 20% accuracy. Therefoer, they need to go to the heavy FEA, CFD etc. and spend days, weeks and sometimes more just to give an intelligent answers.

 

[prost]

Regardless how much (almost) universal agreement the new computer toys make us more productive, evidently employers seem to think they could use more engineers who know how to do hand stress analysis. My evidence? Anectodal, not a science study with correlations no one understands or fancy pictures in a PPT. But here it is--5 years ago, a scan of advertised structural engineering (that is, FEA analysts) would reveal almost NO instances in which the potential employer required "hand stress analysis", while today, I'd guess the percentage is about 25%.

Again, this is anectodal, a gut feel based on repeated observations. It continues to amaze me that anyone could graduate from a university with an engineering degree and not have intimate knowledge of hand structural or fluids analysis. But that's for the employers to address by targeting grads of universities that do emphasize the back of the envelope calculations that used to be standard practice.

and yes, I suppose you could call me an old timer...21 years doing various kinds of engineering (cough...where's my Metamucil? )

 

[rb1957]

i agree in part with tbuelna that consistency is a good thing. but to me, the danger in applying a black box (including FEA) is not appreciating the assumptions within the box, not knowing when they don't apply, nor when you can violate them because of some other feature of the design. this also goes for "rules of thumb".

of course, the other danger in black box stress solutions is (and i think this is the OP's point) that users stop thinking about the issues, and the details, and we'll forget why we did things a certain way, and just continue 'cause that's how we've always done it.

 

[40818]

It seems that so far, a general consensus is that people think it's true. Consider this then, if we had to design and analyse an aircraft today without the FE and modelling tools we have today, do you think the industry could manage the task? Im my opinion, it would probably be a yes, but with a large re-learning curve as we went back over methods and principles long since surpassed. Not saying we should bring back hardy cross et al, but maybe its worth at least keeping the know-how in the business, just in case we have to go back to basics. And i believe thats where it all good engineers start from, there have been simply to many job applicants who can use the tools but cannot simply draw a fixed end beam bending moment, or carry out simple static equilibrium. Maybe if we get the youngsters in the industry to use basic techniques initally instead of allowing them to use short-cuts then they will develop the intuition and understanding that people who i regard as my betters always seem to have.

Regards

Regards

 

[rb1957]

i'd say of course we could design a plane without FE ... people would just look arounf them to see what's flying and just copy it. we might have some test failures, but i doubt we'd have an increase in the number of "smokin' holes (in the ground)".

the designs would not be optimal (tho' i doubt that today's are either) and large scale use of composites would drop back, and i suspect that people would want a simplified set of regulations too.

 

[MiketheEngineer]

I do not think this is industry specific... Remember - these are tools.

Over 25 years ago - I wrote some of the first structural engineeging computer programs used in the wood roof and floor truss industry... Within a few short years -- there was hardly an truss engineer or designer who could or WOULD still do it by "hand". Took too long.

However -- it gave us the time and energy to take on more radical designs and research alternative designs. It reduced costs to the customer. It cut errors. It allowed us to more accurately produce a true engineered design. Previoulsy, too many times a step was overlooked or forgotten or a number got reversed or doubled or halved... you know how that can happen.

Its a tool - like a hammer. You can use it to drive a nail, whack someone over the head or even split your thumb.

You MUST know how to use it... As mentors - we must take the time and eneregy to train the newbies as they come up.

Don't forget - somebody trained you with the best tools he had at the time....

 

[MikeHalloran]

Years ago, decades ago, yes, newcomers were mentored.

No more. Now, I show up to find chaos. Nobody knows what they are trying to do, much less how.

Typically, the last guy who actually knew what he was doing quit in disgust, or was fired for disagreeing with the pointy- haired boss.










Mike Halloran
Pembroke Pines, FL, USA

 

[KENAT]

I'm inclined there's an element of truth to what the OP says, although it can be carried too far.

I'm not in aerospace at the moment and I'm not much of a stress man but when I have interns with stress analysis to do they tend to ask about FEA. I always try and get them to do hand calcs first. It's rare we have anything too complex, mostly earthquake brackets or the like which are easily analyzed with hand calcs. I'll then sometimes let them play with the simple FEA we have included with our CAD to see if the results for their worst case match up.

I only graduated in the 90s but my first thought on stressing was always hand calcs (or maybe excel), in fact my first employer didn’t even have any real organic FEA when I started there.

That said, I’m pretty sure I don’t have the level of knowledge or understanding that many of the more senior guys I worked with probably had at the same point in their career. In fact some of them remembered stuff they’d learnt at school 30+ years ago and hadn’t used much since better than I remembered stuff I’d only learnt maybe 3 years earlier; and most of these guys had come up through apprenticeships not university/college.

Obviously we need to use all the tools available to speed/simplify/enhance the design & analysis process but when using ‘black boxes’ we need to remember the golden rule “Garbage in, Garbage out”. If you don’t understand the basic process then it’s harder to spot the garbage.

 

[jetmaker]

The "black box technology" has led to more efficient analysis at the cost of transparency. As was previously said, one must understand what is going on to fully grasp the limitations of the method. What I have found in the past is that whenever i used a new "black box", I tried to duplicate the method by hand first. This is not always possible as the methods get to be so convoluted which is why they are "black boxed" in the first place.

These tools make us more efficient, but at a cost of transparency and thus requires more oversight of how these tools are used and their output. It is not necessarily a loss of knowledge.

jetmaker

 

[debodine]

I think Kenat may have captured the point of the OP quite elegantly in this statement: "If you don’t understand the basic process then it’s harder to spot the garbage."

I am all for using the best and most efficient tools capable, but removing the "garbage" to locate the "pearls" is (or should be) a core competency of our profession.

debodine

 

[debodine]

In my previous post, replace "capable" with "available". I neglected to use my most important tool (my brain) to perform a quality control check before clicking Submit Post.

 

[Maui]

I was involved in a similar debate decades ago in college when calculators became available that had graphing capability and could execute simple programs. The professors initially would not allow students to use them for exams because the students could store information on their calculators that was supposed to be memorized and understood. The calculators rendered unnecessary a clear understanding of some of the basic theoretical concepts that were required in order to answer certain exam questions. Just input the numbers, and the calculator would spit out the answer. No thought was required, very little effort, and no level of judgement. And I have seen students since that time input numbers in their calculators or computer programs, and obtain answers that were wrong by orders of magnitude, yet they had no idea how far from reality their results were. Frightening. I can see a very similar situation evolving here.

In order to make a reasonable judgement about what the calculated results should be, you need to have a basic understanding of the principles that are involved in determining them. A good engineer will have a method for roughly estimating these values by hand. If you don't have that capability, then you will likely rely on your computer a great deal to output the correct answer. And if something goes wrong, such as violating an inherent assumption about the allowable range for a given input value to the program, then you will have no way of knowing weather or not the answer you obtained is in the ball park. Sound judgement is an important part of the seasoned engineer's skill set, and younger engineers who lack an understanding of the basic principles behind the programs that they use may have a more difficult time reaching that same level of competence. Let's hope that nobody is injured or killed along the way.

Maui

 

[tbuelna]

Consider this: Why does the "perceived" quality of the individual engineer matter? Isn't the real issue the quality/reliability of the end product? If so, then I would argue that the quality/reliability of any engineered product today (cars, airplanes, or whatever) is substantially better than it was 20 or 30 years ago. Our cars now go for over 100,000 miles without a tune-up and are far safer in an impact. And last year, there was not a single crash fatality in the US commercial airline industry. Truly impressive.

Not so 20 or 30 years ago.

How is it that a bunch of undisciplined CAD/FEA monkeys can produce such statistics? Pure luck?

Nope, the engineers today are as good, if not better, than the engineers of yore. Believe me, I've worked with some older guys that were highly unqualified.