Epoxy curing and HETVAL

[fusuym]

ENG TIPS :
Hi,
I’m trying to simulate the heat generated due to the curing of an epoxy resin in a simple model. I have seen a lot of references to the subroutine HETVAL but I’m a bit of a novice in this are so could use some help!
I have the standard Arrenhius relationship between rate of degree of cure and temperature:
dCURE/dTIME= A.exp(-E/R.TEMP)(1-CURE)^n
and heat flux is
dCURE/dTIME*deltaHtot = dH/dTime
where deltaHtot is the energy of reaction.
_____
I’m not sure how to implement CURE in HETVAL.
Can it be a state variable?
Do I need to have an equation of FLUX(2)?
I’m not sure about my PREDEF:
Is the initial degree of CURE a predef?

Here’s my first attempt. Feel free chip in…

SUBROUTINE HETVAL(CMNAME,TEMP,TIME,DTIME,STATEV,FLUX,
1 PREDEF,DPRED)
C
INCLUDE 'ABA_PARAM.INC'
C
CHARACTER*80 CMNAME
C
DIMENSION TEMP(2),STATEV(1),PREDEF(*),TIME(2),FLUX(2),
1 DPRED(*)

C
R= *****
E = *****
A= *****
n= *****
deltaHtot = ***** kJ/gram?
C
CURE= STATEV(1)
Temperature = TEMP(1)


dCURE = A.exp(-E/R.Temperature)(1-CURE)^n
FLUX (1) = dCURE*deltaHtot

FLUX (2)= ?????????

CURE = CURE + dCURE*DTIME

STATEV(1) = CURE



RETURN
END

Thanks for all your help

Yusuf

 

[andraina]

Hi Yusuf,

This subroutine enables the determination of the heat produced by the thermosetting reaction, for each Gauss point, thanks to the degree of cure and degree of cure rate provided by the FIELD array.

Cf. “A FEM coupling model for properties prediction during the curing of an epoxy matrix” (N. Rabearison, C. Jochum, JC. Grandidier) – Computational Material Science45 (2009) 715-724

See you