2011. The focus was to give quick and rather practical introduction to people without prior modeling experience, but with knowledge of mechanics. Some computer literacy was assumed, though basics are reviewed in the Hands-on section.The course did not in reality follow this document, but was based on interactive writing and commenting simple Examples, which were mostly suggested by participants; many thanks to them for their ideas and suggestions.
Hands-on
Shell basics
Directory treeDirectory tree is hierarchical way to organize files in operating systems. A typical (reduced) tree in linux looks like this: Chapter 1. Guided tour Yade Documentation, Release 3rd ed. (continued from previous page) print('mean stress', stress) # if mean stress is below (bigger in absolute value) limitMeanStress, start shearing if stress < limitMeanStress: # apply constant-rate distorsion on the periodic cell O.cell.velGrad = Matrix3(0, 0, .1, 0, 0, 0, 0, 0, 0) # change the function called by the checker engine # (checkStress will not be called anymore) checker.command = 'checkDistorsion()' # block rotations of particles to increase tanPhi, if desired # disabled by default if 0: for b in O.bodies: # block X,Y,Z rotations, translations are free b.state.blockedDOFs = 'XYZ' # stop rotations if any, as blockedDOFs block accelerations␣ →really b.state.angVel = (0, 0, 0) # set friction angle back to non-zero value # tangensOfFrictionAngle is computed by the Ip2_* functor from material # for future contacts change material (there is only one material for all␣ →particles) O.materials[0].frictionAngle = .5 # radians # for existing contacts, set contact friction directly for i in O.interactions: i.phys.tangensOfFrictionAngle = tan(.5) # called from the 'checker' engine periodically, during the shear phase def checkDistorsion(): # if the distorsion value is >.3, exit; otherwise do nothing if abs(O.cell.trsf[0, 2]) > .5: # save data from addData(...) before exiting into file # use O.tags['id'] to distinguish individual runs of the same simulation plot.saveDataTxt(O.tags['id'] + '.txt') # exit the program #import sys #sys.exit(0) # no error (0) O.pause() # called periodically to store data history def addData(): # get the stress tensor (as 3x3 matrix) stress = sum(normalShearStressTensors(), Matrix3.Zero) # give names to values we are interested in and save them plot.addData(exz=O.cell.trsf[0, 2], szz=stress[2, 2], sxz=stress[0, 2],␣ →tanPhi=(stress[0, 2] / stress[2, 2]) if stress[2, 2] != 0 else 0, i=O.iter) # color particles based on rotation amount for b in O.bodies: # rot() gives rotation vector between reference and current position b.shape.color = scalarOnColorScale(b.state.rot().norm(), 0, pi / 2.) # define what to plot (3 plots in total) ## exz(i), [left y axis, separate by None:] szz(i), sxz(i) ## szz(exz), sxz(exz) ## tanPhi(i) # note the space in 'i ' so that it does not overwrite the 'i' entry plot.plots = {'i': ('exz', None, 'szz', 'sxz'), 'exz': ('szz', 'sxz'), 'i ': ('tanPhi',)} # better show rotation of particles (continues on next...
