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# Jintegral and Umat subroutine

Hello,

I have implemented a new constitutive viscoelastic-mechanosorptive creep model for porous materials in the Umat subroutine. Plasticity is not included. I use the thermal-displacement Abaqus analysis, that is, a transient analysis. Now, I would like to calculate the J-integral for a cracked body and, since I am able to define the strain energy density of my constitutive model, I suppose that I should calculate the new expression of the energy in Umat and this energy could be used by Abaqus for calculating the J-integral at each time step of the transient analysis. Actually, into the Abaqus manual I found that for time-dependent problems I should use the C_t integral for creep but in this case I wonder if I have to use both the Umat and the CREEP subroutines. How?

## HI T'm sorry I can't

HI

T'm sorry I can't help you, but I don't understand why you calculate the Energy in subroutine. Abaqus can calculate J-integral directly.

I work about

Modelling and digital simulation of the structures fissured under residual stresses,I have the problem to calculate the J-integral when I have in initial condition residuel stress, because Abaqus define thatInitial stresses are not considered in the definition of contour integrals. Therefore, contour integral calculations for analyses including initial stresses in the regions used for the contour integral calculations will not be correct

I have may others problems see:

Modelling and digital simulation of the structures fissured under residual stressesCan you help me