How can I call the newly added field variables (via a Python script) within the UMAT subroutine?

I am attempting to extract the result data in the ODB file using a Python script, perform mathematical operations on the result data, and store the newly generated data as a new field variable in a frame. I have successfully completed these and stored them as a new field variable.
 

Following is my python sccript:

import odbAccess
from abaqusConstants import *

myOdb = odbAccess.openOdb(path=r"F:\abaqus project\test.odb", readOnly=False)

myFrames = myOdb.steps["Step-1"].frames
fieldoutput0 = myFrames[0].fieldOutputs
myField0 = fieldoutput0["SDV6"]
fieldoutput1 = myFrames[1].fieldOutputs
myField1 = fieldoutput1["SDV6"]
fieldoutput7 = myFrames[7].fieldOutputs
myField7 = fieldoutput7["SDV6"]
fieldoutput8 = myFrames[8].fieldOutputs
myField8 = fieldoutput8["SDV6"]

deltaD1 = myField1-myField0
deltaD2 = myField8-myField7
Num = 10
deltaDamage = deltaD2+(deltaD2-deltaD1)*Num/2
Damage = myField8+(deltaD2+deltaDamage)*Num/2
newField = myFrames[10].FieldOutput(name='TD',description='modified total damage',type=SCALAR)
newField.addData(field=Damage)

myOdb.close()

 

Then I want to use this frame(frame 10) as the starting frame for the restart calculation. The current problem is that I need to use the UMAT subroutine in my calculation. How can I call this new field variable in the subroutine?

When I directly used the name of this field variable in the UMAT subroutine, the result seemed not to have been successfully input into the subroutine.

Part of my UMAT subroutines are listed below:

egyn=props(1)  
egyt=props(2)
deltn=props(3)

delts=props(4)
t=props(5) 
r=props(6)
fk=props(7) 
xi=props(8)

Dtt_old=TD   !How can I call the new field variable?

Smax0=egyn/deltn

Smax=(1-Dtt_old)*Smax0

 

Thank you very much,

Pengcheng Xue