What do you guys do when?

[greznik91]

When you are surprised by the calculation results - I mean when you expect dimensions to be larger but calculations show thats not the case.
There has been few times when I was expecting some beam section dimensions (larger spans) to be a lot larger but after calculations/analysis I was surprised. Do you trust calculations completely or do you also take into account/consider your intuition and make things lil bigger regardless (to be on a safe side)?

That may be a silly question coming from an engineer but sometimes I feel uneasy when my expectations (based on experience) and actual model/analysis results are pretty different.

 

[klaus.]

Whenever I do not feel comfortable with the results or system then I question the results.
Never ever take the results as true once you belly says there might be something wrong...

 

[IDS]

Whenever I do not feel comfortable with the results or system then I question the results.
Never ever take the results as true once you belly says there might be something wrong...

Agreed.

Some words of advice from early in my career that I always remember:

Before you submit any work to the next stage, always ask yourself, are you happy with it?

Doug Jenkins
Interactive Design Services

http://newtonexcelbach.wordpress.com/

 

[LittleInch]

That's what comes with experience - A feeling that it just "isn't quite right".

Then you need to take a deep breath and really go through in minute details all the inputs, data and how the particular item was calculated and INPUT INTO the SOFTWARE.

Question every link, data source, value from some other location.

Occasionally you will get it wrong, but more times you find the error.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[dcarr82775]

If it feel wrong it probably is. If it feels wrong by about a factor of 12 chances are the units got messed up

 

[EngineeringEric]

I go get a coffee or lunch and come back and redo it. forget what i did last time and at recheck the loading, the inputs, sometimes confirm ballpark with an AISC table. most the time my gut is more correct than my pencil/calculator when it comes to orders of magnitude.

but if i get the unexpected answer again? I will either ask a colleague to confirm it or put a big 'Review' post-it on it to check once again completely fresh for the final time and then accept it.

 

[JoshPlumSE]

It depends on the difference in cost. A lot of times the larger size isn't much of a cost difference, so I just go with my gut.

However, when I have free time, I try to examine why my gut might be giving me different results from my calculations. The goal being to better understand where my intuition is coming from and to better understand when and where it might not be as accurate as I think it is.

 

[racookpe1978]

First - Check it yourself, as repeated above.
If the result still "smells wrong" then peer-check it.
Also, pass it through your boss informally - "This calculation doesn't seem right, would you look at it and let me know what I may have overlooked before we release it. "

 

[271828]

Option 1: Use another method or tool, and compare. If you're using a program, then do the calcs manually or use a design aid such as a table. After this, hopefully I understand the discrepancy.

Option 2: Peer review. After this, hopefully I understand the discrepancy.

I will not do the following: "...do you also take into account/consider your intuition and make things lil bigger regardless (to be on a safe side)?" What if my intuition leads me to bump it up 30%, but the calculations were unsafe by 100%? With this approach, I presumably do not know what was wrong with my calculations or the method.

 

[jike]

Remember, it may not be an actual mistake in the calculation, but it might be the assumptions that you made before the calculation. For example, how much load is being attracted to the beam.

When I design something, I like the finished product to look right. It gives confidence to the builder and the final user.

 

[berkshire]

With this kind of un easy feeling , I remember my boss getting involved with a bunch of calculations I had done, after about 20 minutes we had isolated the problem .
I will always remember his comment on the matter. " The mistake is ALWAYS in the part that you KNOW is correct. ", A not too subtle way of saying check everything.
B.E.

You are judged not by what you know, but by what you can do.