How to plot damage ratio curve

Hi Tina,

If you are using cohFrictMat, I guess that you are also using cohFrictPhys and Law2_ScGeom6D_CohFrictPhys_CohesionMoment (right?).

In this case, you should be able to loop over interactions at any time of the simulation and count the cohesive/frictional contacts by checking if the cohesionBroken attribute is false (cohesive contact) or true (frictional contact) using lines such as:

nbCohBond=0
for i in O.interactions:
  if not i.isReal : continue # not mandatory
  if i.phys.cohesionBroken==False:
    nbCohBond+=1

You could include these into a function that you would run periodically during your simulation (e.g. using PyrRunner()) and thus get the evolution of the number of cohesive contacts. By running it before your simulation starts, you will then be able to compute the ratio of broken bonds / initial bonds.

I hope it helps

Thanks Luc,

According to your code, I wrote the following script, but got an error (File "impact.py", line 104, in <module>
    damageRatio=numBroCohBonds/sumCohBonds
ZeroDivisionError: integer division or modulo by zero)

Here is a segment of my code:

#calculate total intact cohesive bonds
global sumCohBonds
sumCohBonds=0
for b in O.interactions:
    if b.phys.cohesionBroken==True:
        continue
    sumCohBonds+=1

#define a function to calculate broken cohesive bonds
global damageRatio
numBroCohBonds=0
def damageRatio():
    for b in O.interactions:
        if not b.isReal:
            continue
        if b.phys.cohesionBroken==True:
            numBroCohBonds+=1
damageRatio=numBroCohBonds/sumCohBonds
plot.saveDataTxt('data/damageratio.txt')

#define a function to plot damage ratio
def addPlotData():
    plot.addData(t=O.time,dr=damageRatio)
plot.plots={'t':('dr')}
plot.plot()

Thanks in advance.

Apparently, you divide something by zero...

Did you check the value of sumCohBonds by printing it before using it in your function damageRatio? Type print sumCohBonds just after its calculation in your script and you should see its value in the terminal.

Actually, did you compute it at iteration 0 of your simulation or at iteration 1? I guess it is null at iteration 0 since the contacts haven't been looped over yet. Try O.step() just before computing sumCohBonds and let me know.

Luc

Hi Luc,

Thanks for your patience, I adjusted my code and It goes well, but the output is wrong,because the number of broken bonds does not grow gradually with the increase of computation time (number of broken bonds: 1,23,42,32,15...). Here is a segment of my code.

O.step()
# calculate the total intact cohesive bonds
global sumCohBonds
sumCohBonds=0
for b in O.interactions:
    if b.phys.cohesionBroken==True:
        continue
    sumCohBonds+=1
print 'first time:{}'.format(sumCohBonds)

numBroCohBonds=0
def damageRatio():
    for br in O.interactions:
        if br.phys.cohesionBroken==False:
            continue
    numBroCohBonds+=1 # calculate broken bonds
damageRatio=numBroCohBonds/float(sumCohBonds)
print numBroCohBonds,damageRatio
print 'second time:{}'.format(sumCohBonds)

Thanks Luc Scholtès, that solved my question.