abq中的random property问题（from YaHoo abq group）

linqus

　　question：

　　The material properties in my input file should be chosen 'randomly' from a set, Does anybody know how I could introduce a random material property to my input file? Is there any easy was by using python script?

　　answer：

　　(1) I don't know how to introduce a random variable directly, but you could certainly set up a design study where you specified a number of values

　　that you chose randomly. This would repeat the run for each value of

　　the random variable, which could potentially get expensive. I've used

　　this process to find the sensitivity of a rigid body mechanism solution

　　to a number of uncertain parameters and it worked very well, but I got

　　each run down to less than a minute.

　　(2) A web search on "python & random" yields a number of links with information on generating random numbers using Python.

　　(3) that's a good question. I don't think Ab can deal with random fields though, as Ansys. Instead of a simple search using a Monte Carlo engine, I'd make use of multiple available codes for random fields, and there is a body of literature increasing within this area. Some very good papers are available about Random Fields Discretization...I shall give you some links if you insist.

　　(4) The best way would almost certainly be to have a user subroutine to do it, using FORTRAN but you might not be fixed up for that. Assuming that your input files are relatively small (compared with output files) then make a set of copies and pick numbers from a random number table to edit into each one. It's a well regarded way to do it. If you change your model, use the same set again so you you know that changes are due to your modeling and not any bias in the random numbers. If you really want lots then you can write a script in any programming language, and get it to submit the job as well - I have used MATLAB in the past to do that. I expect "C" or VisualBASIC or Pascal would be good, or a macro in a good text editor. Your "academic" challenge might be to find the right distribution for your material.

tonan_888@163.c