Ah... I should have read Luc's post before sending my own reply... Thanks.
Bruno Luc Sibille a écrit : > Hi, > > There is several definitions of strain, see for instance the page > about strain computation in Wikipedia: > > http://en.wikipedia.org/wiki/Deformation_(mechanics) > > > If I'am right (but please verify to be sure): > > ** Log means ln (natural logarithm), > > ** The way to compute strains in Yade is valid for large strains (or > large transformations), whereas the definition > epsilon=(length-length0)/length0 is valid under the hypothesis of small > strains. > > ** compare the results given by ln(length/length0) and > (length-length0)/length0, it is quasi the same for strains lower than > 20% to 30%, when strains become too much important > (length-length0)/length0 is no longer valid. > > Best > > Luc > > > > 张林 a écrit : > >> Hi everyone >> These days I'm a little puzzled with the strain compution in >> TriaxialstressController.cpp ,just as follows: >> >> strain[0] = Mathr::Log(width0/width);//Eq(1) >> strain[1] = Mathr::Log(height0/height);//Eq(2) >> strain[2] = Mathr::Log(depth0/depth);//Eq(3) >> volumetricStrain=strain[0]+strain[1]+strain[2];//Eq(4) >> >> IIRC,Log means not log10 but ln as usual .Is it right? >> Eq(1 to 3) is different from the common compution of strain like: >> epsilon=(length-length0)/length0 >> and, in PFC3D manuals(V3.0)->users' guide->problem solving with pfc3d >> Page 47, I found another Eq for strain compution: >> epsilon=(L-L0)/((L0+L)/2) >> Are the 3 methods all right? They're designed for different fields? >> >> Thanks for any suggestion. >> Regards. >> Zhang Lin >> [EMAIL PROTECTED] >> 2008-11-25 >> >> >> ------------------------------------------------------------------------ >> >> _______________________________________________ >> Mailing list: https://launchpad.net/~yade-users >> Post to : [email protected] >> Unsubscribe : https://launchpad.net/~yade-users >> More help : https://help.launchpad.net/ListHelp >> > > -- _______________ Chareyre Bruno Maitre de conference Grenoble INP Laboratoire 3SR - bureau E145 BP 53 - 38041, Grenoble cedex 9 - France Tél : 33 4 56 52 86 21 Fax : 33 4 76 82 70 43 ________________ _______________________________________________ Mailing list: https://launchpad.net/~yade-users Post to : [email protected] Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
