Square Coupon with SH3N Elements

The following element formulation is evaluated:
  • /PROP/TYPE1 (SHELL), QEPH shell formulation Ish3n=0, 5 integration points over the thickness.

    For each loading, the triaxiality and plastic strain curves are represented at failure.

Table 1. Results for SH3N element
Pure Tensile Pure Shear Pure Compression Plain Strain Tension Biaxial Tension










As expected, the elements failed once they reached the plastic strain, then the stress decrease:
ε f = 0.12 MathType@MTEF@5@5@+= feaahGart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbb a9q8WqFfeaY=biLkVcLq=JHqpepeea0=as0Fb9pgeaYRXxe9vr0=vr 0=vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOqaaabaaaaaaaaape GaeqyTdu2damaaBaaaleaapeGaamOzaaWdaeqaaOWdbiabg2da9iaa icdacaGGUaGaaG4maaaa@3C42@
Pure tensile
ε f = 0.37 MathType@MTEF@5@5@+= feaahGart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbb a9q8WqFfeaY=biLkVcLq=JHqpepeea0=as0Fb9pgeaYRXxe9vr0=vr 0=vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOqaaabaaaaaaaaape GaeqyTdu2damaaBaaaleaapeGaamOzaaWdaeqaaOWdbiabg2da9iaa icdacaGGUaGaaG4maaaa@3C42@
Pure shear
ε f = 0.62 MathType@MTEF@5@5@+= feaahGart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbb a9q8WqFfeaY=biLkVcLq=JHqpepeea0=as0Fb9pgeaYRXxe9vr0=vr 0=vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOqaaabaaaaaaaaape GaeqyTdu2damaaBaaaleaapeGaamOzaaWdaeqaaOWdbiabg2da9iaa icdacaGGUaGaaG4maaaa@3C42@
Pure compression
ε f = 0.096 MathType@MTEF@5@5@+= feaahGart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbb a9q8WqFfeaY=biLkVcLq=JHqpepeea0=as0Fb9pgeaYRXxe9vr0=vr 0=vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOqaaabaaaaaaaaape GaeqyTdu2damaaBaaaleaapeGaamOzaaWdaeqaaOWdbiabg2da9iaa icdacaGGUaGaaG4maaaa@3C42@
Plain strain tension
ε f = 0.42 MathType@MTEF@5@5@+= feaahGart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbb a9q8WqFfeaY=biLkVcLq=JHqpepeea0=as0Fb9pgeaYRXxe9vr0=vr 0=vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOqaaabaaaaaaaaape GaeqyTdu2damaaBaaaleaapeGaamOzaaWdaeqaaOWdbiabg2da9iaa icdacaGGUaGaaG4maaaa@3C42@
Biaxial tension

Effect of /FAIL/BIQUAD parameters on damage

The following parameters are tested:
  • ICOUP=1 with S-Flag=2
    • DCRIT=0.5
    • DCRIT=0.8
    • DCRIT=0.95
  • ICOUP=2 with S-Flag=3
    Figure 1. Effect of DCRIT parameter on stress softening triggering


With ICOUP=1, the critical damage parameter DCRIT is tested with different values. The more the value of DCRIT is increased, the later the softening is applied on the stress. The exponent parameter EXP is used to control the shape of the stress softening, so that it is nonlinear when EXP is different from 1.

With ICOUP=2, the instability curve represents the criterion that must be reached to trigger stress softening, implying the beginning of the strain localization and then necking, especially observed at high stress triaxiality.