I am implementing Johnson Cook type plasticity with rate dependence in VUMAT subroutine.

I am also using NLGEOM for large strain calculation.

1. My first question is that does my vumat is taking care of large strain formulation in plasticity?

The documentation says that Johnson Cook is applicable for large strain. But in my subroutine, I just define

deqps = e0(.)*exp(1/C(R-1))

peeq = peeqOld + deqps

yieldNew = [A + B*(peeq)^n]

I keep the temperature term = 1 always.

2. My second question is that how to update stresses?

I dont change the formulation of stress updating which is

factor = yieldNew/( yieldNew + thremu*deqps )

thermu = 3/2 * E/(1+v)

stressNew(11) = deviatoricS11*factor +smean

is it correct?

3. I also intend to define damage similar to Lemaitre's CDM formulation, but I have a stupid doubt which is

should I update the deviatoric stresses with damage as

s11(dev, damage) = (1-Ddev)*s11(dev)

or should I change the Elastic modulus in plastic calculation with damage factor.

Thanks in advance.