Hello to everyone,
I am using Abaqus CAE to model machinig. I want to include the residual stress (material and machining residual stress) into my model.
Firstly I want to introduce homogeneous residual stress in Shell surface (I am using Shell element S4R and reduced integration).
In the future my intention will be to introduce non-uniform residual stress in Shell surface.
Does anybody have the example of how to employ SIGINI in Shell element.
I do not find in abaqus documentation any example of how to apply in Shell element.
The following code is for solid element. How can I modify in order to applying the load in Shell element?
SIGINI(SIGMA,COORDS,NTENS,NCRDS,NOEL,NPT,LAYER,
>
> 1 KSPT,LREBAR,REBARN)
> C
> INCLUDE 'ABA_PARAM.INC'
> C
> DIMENSION SIGMA(NTENS),COORDS(NCRDS)
> CHARACTER*80 REBARN
>
> SIGMA(1)=0
> SIGMA(2)=0
> SIGMA(3)=1000
> SIGMA(4)=0
> SIGMA(5)=0
> SIGMA(6)=0
>
> RETURN
> END
Thanks in advance,
Ane
As ABAQUS SIGINI define initial strain (not stress) at material point, each element has the uniform initial strain, if each element has only one material point.
I did not find how many material points in a Shell element but I think these material points distribute along the thickness of Shell element. So I think you can input residual stress in Shell surface by define COORDS of surface.
Xueyuan Wang is truth that sigini define initial strain (not stress) at material point. So, as you said it is enough to apply residual stress in Shell surface. I am trying to do it but the point is, I have not any experience with fortran and I do not know how define COORDS of surface.
Do you have any idea how can I do?
Thanks in advace for your help.
DIMENSION SIGMA(NTENS),COORDS(NCRDS)
CHARACTER NAMES(2)*80
Real RS(253,2), RST(353,2), RSI(250,2)
C residual stesses input by array
RS(1,1)=0.0;RS(1,2)=198.212
RS(2,1)=0.500672;RS(2,2)=254.714
RS(3,1)=1.00136;RS(3,2)=337.16
C FE model is at 0 mm to 87.5 mm position
DO 20 i=1,252,1
IF( COORDS(2) .GE. RS(i,1) .AND. COORDS(2) .LE. RS(i+1,1) ) THEN
C Value by linear interpolate
SIGMA(1)=RS(i,2)-( RS(i,2)-RS(i+1,2)) / (RS(i,1)-RS(i+1,1))
1 *(RS(i,1)-COORDS(2) )
SIGMA(2)=0
SIGMA(3)=0
ENDIF
20 Continue
An example of use COORDS to define stress.
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