*MAT_120 (GURSON)

LS-DYNA Input Interface KeywordDefines a nonlinear elasto-plastic based on the Gurson constitutive law, which is used to model visco-elastic-plastic strain rate dependent porous metals.

Format

(1) (2) (3) (4) (5) (6) (7) (8)
*MAT_120 or *MAT_GURSON
mat_ID ρ i E Nu A N q1 q2
fc fI ε N SN fN B ATYP fF
EPS1 EPS2 EPS3 EPS4 EPS5 EPS6 EPS7 EPS8
ES1 ES2 ES3 ES4 ES5 ES6 ES7 ES8
Blank line
LCSS LCFF NUMINT LCF0 LCFC LCFN

Definition

Field Contents SI Unit Example
mat_ID Material identifier.

(Integer)
ρ i Initial density .

(Real)

 [ kg m 3 ]
E Young's modulus.

(Real)

 [ Pa ]
Nu Poisson's ratio.

(Real)
A Yield stress.

(Real)

 [ Pa ]
N Hardening exponent (used only if ATYP=1 and LCSS=0).

(Real)
q1, q2 Damage material parameters.

(Real)
fc Critical void volume fraction at coalescence.

(Real)
fI Initial void volume fraction.

(Real)
ε N Nucleated effective plastic strain.

(Real)
SN Gaussian standard deviation.

(Real)

 [ Pa ]
fN Nucleated void volume fraction.

(Real)
B Hardening parameter (used only for ATYP=2).

(Real)

 [ Pa ]
ATYP Hardening type
= 0
Perfect plastic, σ y = A MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeaaciGaaiaabeqaamaabaabaaGcbaGaeq4Wdm3aaS baaSqaaiaadMhaaeqaaOGaeyypa0Jaamyqaaaa@3AB4@
= 1
Power law, σ y = A ⋅ ε p + A E A E 1 N MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeaaciGaaiaabeqaamaabaabaaGcbaGaeq4Wdm3aaS baaSqaaiaadMhaaeqaaOGaeyypa0JaamyqaiabgwSixpaabmaabaWa aSaaaeaacqaH1oqzdaWgaaWcbaGaamiCaaqabaGccqGHRaWkdaqada qaamaalaaabaGaamyqaaqaaiaadweaaaaacaGLOaGaayzkaaaabaWa aSaaaeaacaWGbbaabaGaamyraaaaaaaacaGLOaGaayzkaaWaaWbaaS qabeaadaWcaaqaaiaaigdaaeaacaWGobaaaaaaaaa@48DF@
= 2
Linear hardening, σ y = A + E ⋅ B E − B ε p MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeaaciGaaiaabeqaamaabaabaaGcbaGaeq4Wdm3aaS baaSqaaiaadMhaaeqaaOGaeyypa0JaamyqaiabgUcaRmaabmaabaWa aSaaaeaacaWGfbGaeyyXICTaamOqaaqaaiaadweacqGHsislcaWGcb aaaaGaayjkaiaawMcaaiabew7aLnaaBaaaleaacaWGWbaabeaaaaa@4650@
= 3
8 points curve defined with EPS1 - EPS8 and ES1 - ES8.

(Integer)
fF Critical void volume fraction at ductile fracture.

(Real)
EPS1 - EPS8 Plastic strain data points.

(Real)
ES1 - ES8 Yield stress data points.

(Real)

 [ Pa ]
LCSS Stress versus plastic strain curve or table identifier.

(Integer)

 [ Pa ]
LCFF Load curve ID defining critical void volume fraction at ductile fracture fF as a function of element length. 2

(Integer)
NUMINT Element failure rule.
> 0
Number of integration points which must fail before the element is deleted.
< 0
Percentage of integration points through the thickness which must fail before the element is deleted.

(Integer)
LCFI Load curve ID defining initial void volume fraction fI as a function of element length. 2

(Integer)
LCFC Load curve ID defining critical void volume fraction at coalescence fc as a function of element length. 2

(Integer)
LCFN Load curve ID defining nucleated void volume fraction fN as a function of element length. 2

(Integer)

Comments

  1. This keyword maps to /MAT/LAW52 (GURSON).
  2. With the current version, only the first ordinate of the curve is used.
  3. The option “_TITLE” can be added to the end of this keyword. When “_TITLE” is included, an extra 80 characters long line is added after the keyword input line which allows an entity title to be defined.