Question #675377 on Yade changed: https://answers.launchpad.net/yade/+question/675377
Bruno Chareyre proposed the following answer: Hi Mehdi, If I understand correctly the main problem is that you expect from the transformation tensor properties which only apply in the small strain + small rotation approximation. Typically: exy =0.5 (O.cell.trsf[0,1] + O.cell.trsf[1,0]). The problem is this is not a frame independent quantity in large deformations. When you don't reset trsf to identity it has components of the order of 0.7, which is far away from a "small" thing. This is reflected by the fact that your definition of shear is not frame independent. It is to be expected. What needs to be constant is the change of trsf, with or without reseting it to identity. And it is the case, see code below replacing your last section. Note that the composition of transformations implies products, not additions, therefore calculating an "increment" between two transformations needs multiplication by an inverse, while you where doing substractions. Cheers Bruno ######## to be activated for comparison O.cell.trsf=Matrix3.Identity O.run(1,True) initTrsf= O.cell.trsf ############## dummy_deps = -1 triax.goal=[-100,-100 ,triax.stressTensor[2,2]] #-100 is meaningless. Just to make sure straining is occurring in the right diretion nT = 100 O.run(nT,True) #print "incremental trsf:", dF=O.cell.trsf*(initTrsf.inverse()) print 'dFxx=', dF[0,0], ' dFyy=',dF[1,1], ' dFxy=',dF[0,1] Bruno -- You received this question notification because your team yade-users is an answer contact for Yade. _______________________________________________ Mailing list: https://launchpad.net/~yade-users Post to : [email protected] Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
