Abaqus python programming problem

[Galey]

Hi everybody,

I have a problem with programming script in python, which is a part of my thesis.
I am trying to write script which will calculate weld fatigue life based on Verity method.
I try to get nodal forces and moments in local coordinate system.
Local system is creating based on nodes and elements path.

Everything goes ok, but when I want to read nodal forces in local coord system following error occured:

http://speedy.sh/BuKQx/CoordError.JPG

I don't know what I am doing wronge. Anybody can help me so solve this problem?

Here you have my "functions.py" file where I've put all important functions. 'GetForces' should read mentioned nodal forces.
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from math import*
from abaqus import*
from odbAccess import*
from abaqusConstants import*
#from os import*

def GetOdbPath (nods):
temp=str(nods)
OdbPath=temp[(temp.index("'")):temp.index(')')]
return str(OdbPath)

def GetInstance (nods):
temp=str(nods)
Inst=temp[(temp.index('[')+1):temp.index(']')]
return str(Inst)

def CalcNodsDistance (nods,OdbPath,Step,Inst):
NodsDistance=[]
NewCoordsX=[]
NewCoordsY=[]
NewCoordsZ=[]
odb = session.openOdb(name='Baza', path='Test.odb', readOnly=TRUE)
step_temp = odb.steps.values()[Step-1].name
lastFrame = odb.steps[step_temp].frames[-1]
displacement=lastFrame.fieldOutputs['U']
fieldValues=displacement.values

#All paths to get nodal coordinates
assembly=odb.rootAssembly.instances[nods[0].instanceName]
for i in range(len(nods)):
for j in range (len(assembly.nodes)):
if assembly.nodes[j].label==nods.label:
NewCoordsX.append(assembly.nodes[j].coordinates[0]+fieldValues[j].data[0])
NewCoordsY.append(assembly.nodes[j].coordinates[1]+fieldValues[j].data[1])
NewCoordsZ.append(assembly.nodes[j].coordinates[2]+fieldValues[j].data[2])
elif len(NewCoordsX)==len(nods):
break
else:
continue
#NodsDistance
for i in range(len(nods)-1):
NodsDistance.append(sqrt(((NewCoordsX[i+1]-NewCoordsX)**2)+((NewCoordsY[i+1]-NewCoordsY)**2)+((NewCoordsZ[i+1]-NewCoordsZ)**2)))


return NodsDistance

def ThirdCoordNod (elems,nods):
ThirdCoordNod=[]
for i in range(len(elems)-1):
for k in range(4):
temp=elems.connectivity[k]
for j in range(4):
temp2=elems[i+1].connectivity[j]
if (temp==temp2 and temp!=nods[i+1].label):
ThirdCoordNod.append(temp2)
else:
continue
#Third Node for last element
temp=list(elems[-1].connectivity)
temp.remove(ThirdCoordNod[-1])
temp.remove(nods[-1].label)
temp.remove(nods[-2].label)
ThirdCoordNod.append(temp[0])
return ThirdCoordNod



def CreateCoordSystems (nods,thirdnods,OdbPath):
odb = session.openOdb(name='Baza', path='Test.odb', readOnly=TRUE)
#scratchOdb = session.ScratchOdb(odb)
CSYS=[]
thirdnods2=[]
assembly=odb.rootAssembly.instances[nods[0].instanceName]
for j in range(len(thirdnods)):
for i in range(len(assembly.nodes)):
if (assembly.nodes.label==thirdnods[j]):
thirdnods2.append(assembly.nodes)
else:
continue
for k in range(len(thirdnods2)):
CSYS.append('CSYS'+str(k))
#scratchOdb.rootAssembly.DatumCsysByThreeNodes(name=CSYS[k], coordSysType=CARTESIAN, origin=nods[k+1], point1=nods[k], point2=thirdnods2[k])
odb.rootAssembly.DatumCsysByThreeNodes(name=CSYS[k], coordSysType=CARTESIAN, origin=nods[k+1], point1=nods[k], point2=thirdnods2[k])
return CSYS

def GetForces(nods,Step,Csyses):
odb=session.openOdb('Test.odb')
step_temp = odb.steps.values()[Step-1].name
forces=[]
for i in range(len(nods)):
Csys_temp=Csyses
dtm=session.openOdb('Test.odb').rootAssembly.datumCsyses[Csys_temp]
forces.append(session.openOdb('Test.odb').steps[step_temp].frames[-1].fieldOutputs['NFORC2'].getTransformedField(datumCsys=dtm).getSubset(region=nods).values.data[1])
return forces

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Thank a lot