/MAT/LAW1 (ELAST)

Block Format Keyword This keyword defines an isotropic, linear elastic material using Hooke's law. This law represents a linear relationship between stress and strain. It is available for truss, beam (type 3 only), shell and solid elements.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
/MAT/LAW1/mat_ID/unit_ID or /MAT/ELAST/mat_ID/unit_ID
mat_title
ρ i                
E υ            

Definition

Field Contents SI Unit Example
mat_ID Material identifier

(Integer, maximum 10 digits)

  
unit_ID Unit Identifier

(Integer, maximum 10 digits)

  
mat_title Material title

(Character, maximum 100 characters)

  
ρ i Initial density

(Real)

 [ kg m 3 ]
E Young's modulus

(Real)

 [ Pa ]
υ Poisson's ratio

(Real)

  

Example (Elastic - Steel)

#RADIOSS STARTER
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/UNIT/1
unit for mat
                  Mg                  mm                   s
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#-  2. MATERIALS:
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/MAT/ELAST/1/1
Steel
#              RHO_I
             7.85E-9                   0
#                  E                  nu
              210000                  .3
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#ENDDATA
/END
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

Comments

  1. This material law is used to model purely elastic materials. The material stiffness is determined by only two values: the Young's modulus (E), and Poisson's ratio ( υ ). The shear modulus (G) can be computed using E and ν , as:(1)
    G= E 2( 1+ν )
  2. The stress-strain relationship can be represented as shown:(2)
    [ ε 11 ε 22 ε 33 2 ε 23 2 ε 31 2 ε 12 ]=[ ε 11 ε 22 ε 33 γ 23 γ 31 γ 12 ]= 1 E [ 1 −ν −ν 0 0 0 −ν 1 −ν 0 0 0 −ν −ν 1 0 0 0 0 0 0 2(1+ν) 0 0 0 0 0 0 2(1+ν) 0 0 0 0 0 0 2(1+ν) ][ σ 11 σ 22 σ 33 σ 23 σ 31 σ 12 ]
  3. The value of density is always used in explicit simulations and it may also be used in static implicit simulations to reach a better convergence in quasi-static analysis.
  4. Global integration approach is applied to LAW1 and shell elements (/PROP/TYPE1 (SHELL)), when the number of integration points through the shell thickness is different from NP=1 (membranes).
    Note: Failure models are not available in the case of global integration. LAW2 and LAW27 with very high yield stress may be used as a substitution to LAW1 in these cases.