I would like to modelize the bending of a piece of tube :
a straight tube maintained in a bracket is bent thanks to a moving part exercing pressure on the straight tube .
I first would like to know which way I should use to modelize the tube ?
and then I suppose I would need to use soft bodies ?
I think this should get you started. Remember, you need enough vertices for a smooth bend. In the case of a tube, I’d suggest to add some horizontal (I assume you added the tube in top view and are now working in front or side view) loop Cuts (select one vertical edge, hit Ctrl+R and then just enter a number to specify the number of cuts). To finish the effect off, a subsurf modifier will help.