Compute integral in Abaqus subroutines

[silversea]

Dear All,

I’m trying to model the effects of fire on composite materials in Abaqus using UMATHT subroutine. In the governing equation that considers the effect of the thermal processes on the temperature–time response of a polymer laminate, there is a quantity named “mass flux of pyrolysis gases” (Mdot) that should be obtained using an integral equation of ‘rate of density’ (dRo/dt) along the spatial coordinate in the through-thickness direction:

Mdot = int(dRo/dt)dx

I used “the solution-dependent state variables” to compute ‘rate of density’ (dRo/dt), therefore I have this variable at all nodes in each time increment.
As you know, in UMATHT, Abaqus can only get some info of ‘Current Integration Point’. But in order to compute the above integral, it’s needed to have the variables at other nodes in the through-thickness direction.

How can I get the information and variables defined at other nodes in UMATHT to compute above integral?
I know that Abaqus store the amount of all variables at all nodes in analysis process stage, but how can I reach to this information?

Any help in this matter would be greatly appreciated.

Best Regards,
Silversea

[lumpwood]

You can get nodal results for each integration point through field variables provided the nodes and integration point share the same element. Otherwise you may have to look toward common blocks for storing nodal data.

[silversea]

Many thanks lumpwood.

I did it using common blocks.

[jimmy45]

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