nubies help

Hello,
Having done finite elements till my studies, there are more than ten years, I have to model a complex problem: a flexible water reservoir on which various efforts are apply.
Wishing to work in open source, I sought a software able to do that. My question is: what do you recommend?

Salome +code aster code saturn or
Salome +elmer
or....

In short, what tools you think are best suited to my work, so as not to increase learning software before solving my problem.

Sorry for my bad english and thanks in advance,
Jluc Mercier