Simulation of Initial Bending Stress on Cross-section of Beam Elements

[CNTJY]

Hi,

I'm now working on simulation of initial bending stress on cross-section of beam elements. According to my understanding of user subroutine, i.e. SIGINI, can be used to do that. I developed the following codes which I though should work wel. However, the command lind, i.e. IF (NPT.EQ.3) THEN, did not work. It seemed that initial stress could only be applied uniformly on cross-section. Could you please help check what's wrong with my codes? Many thanks!

Note: 1) Based upon my model, tensile and compressive stresses should be applied to integration points 1 and 3, respectively (I just tested to define the compressive stress for integration 3. So, the commandlines for defining tensile stress for integration point 1 were not covered. I hope that will not get you guys confused!). A sketch showing the integration points was attached for your information.
2) A portion of model, i.e. element No. 100 ~ 150, was what initial bending stress was defined for.


SUBROUTINE SIGINI(SIGMA,COORDS,NTENS,NCRDS,NOEL,NPT,LAYER,
1 KSP,LREBAR,NAMES)
C
INCLUDE 'ABA_PARAM.INC'
C
C
DIMENSION SIGMA(NTENS) ,COORDS(NCRDS)
CHARACTER NAMES(2)*80
C
NAMES(2)='B31'
SIGMA(1)=0.0
SIGMA(2)=1.0E7
C
IF (NOEL.GE.100.AND.NOEL.LE.150) THEN
IF (NPT.EQ.3) THEN
SIGMA(1)=-1E7
SIGMA(2)=0.0
END IF
END IF
RETURN
END