ansys and reliability analysis

[ananan88]

Dear friends:
I'm learning the use of ANSYS to perform a reliability analysis. But I met with some questions that disturb me very much.These questions are:

1.How to perform a reliability analysis for each elements? I know the method to calculate the failure probability of one element by using Monto-Carlo method,but I don't know how to desiganate the response parameters to many parameters.

2.After performing the reliability analysis, I can see the probability by using PDPROB. But I want to send the probability value to a variable such as PF. How should I do?

3.If I have get the probability of each elements, how can I plot the curve of that probability?

Thank you very much!

 

[shakleeng]

Try to use @Risk or Crystal Ball add=in program in Excel

 

[Mccoy]

The softwares shakleeng suggests are the standard in Montecarlo simulation, making up great tools for reliability analysis, but you should first build your model in Excel and then apply the analysis after defining the uncertain variables.
Shakleeng, do you use those add-ins routinely? They are popular in other areas but maybe they are just starting to get used in the field of geotechnical engineering, pretty powerful tools.

 

[BigH]

Just as a footnote - you might want to see M.E. Harr's book on probabilistic geotechniques - it was written about 20 years ago, I think, but it is pretty good. Sorry I don't have the exact name off-hand.

 

[Mccoy]

BigH,
that one is an excellent book I would reccomend to anyone.
As a matter of fact, Milton Harr wrote 2 main books on the subject:

Mechanics of particulate media: a probabilistic approach, 1977, mc Graw hill

Reliability-based design in civil engineering, 1987, mc Graw hill

I read the latter, very simple, comprehensive and practical.

The former (regretfully I couldn't get hold of it)is more specific, it deals among other things with the author's method to calculate stresses within soil, an evolution of Bousinessq's traditional technique (a chapter on this appears on Fang's Foundation engineering handbook).

One more textbook I would suggest is the following by Laszlo Rethati, a professor at Budapest university:
Probabilistic solutions in geotechnics, 1988, Elsevier

A very recent addition to this gallery is Baecher and Christian's :
Reliability and statistics in geotechnical engineering, 2003, Wiley ,
600 pages packed with state of the art specific material on reliability analysis, Bayesian analysis, random fields and more...
Maybe better taken in small doses, as I'm doing.

Well BigH, you enjoying the olympics? Italy fared pretty good so far with 7 gold medals so far, how about Canada? Good performances by all athletes tough, far better then watching the pampered and way,way-overpaid soccer guys.

 

[BigH]

Yeah - I've got two copies of the first Harr book in storage - will have to look into the second one. Thanks for the info on later stuff.

Canada in olympics - well, the women's hurdles are coming up and they have a chance at a gold in it. Since we are "heavy" into India here, not much info on the Canadians but I feel sorry for that US shooter who had the gold wrapped up - needed to just hit the target on the last shot and shot the wrong target - Ouch, that hurt!!

Best to all -

 

[Mccoy]

I just looked up the medals table, Canada already won a gold too, but they don't say where. Italy gained 8 golds, maybe we'll make it to 10, that would be darn good. India, I saw, didn't gain much, I wonder why, with such a human resources potential (after all population is only second to China).
China government is real keen on sports, they won 23 golds, same as the US so far. Good propaganda for the new Chinese system.