MATX82

Bulk Data Entry Defines additional material properties for Ogden material for geometric nonlinear analysis. This material is used to model rubber, polymers, and elastomers.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
MATX82 MID                
  LAW MU1 ALFA1 D1 MU2 ALFA2 D2    
    MU3 ALFA3 D3 MU4 ALFA4 D4    
    etc              

Example

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
MAT1 102 10.0   0.495 6.0E-10        
MATX82 102                
  LAW 0.10 2.0   -0.010 -2.0      

Definitions

Field Contents SI Unit Example
MID Material ID of the associated MAT1. 1

No default (Integer > 0)

 
LAW Indicates that material parameters MUi, ALFAi, and Di follow.  
MUi Parameter μ i

(Real)

 
ALFAi Parameter α i

(Real)

 
Di Parameter Di

(Real)

 

Comments

  1. The material identification number must be that of an existing MAT1 Bulk Data Entry. Only one MATXi material extension can be associated with a particular MAT1.
  2. MATX82 is only applied in geometric nonlinear analysis subcases which are defined by ANALYSIS=EXPDYN. It is ignored for all other subcases.
  3. NU is defined on the corresponding MAT1. For material without Poisson effect, a small NU (for example, =1.E-10) should be defined.
  4. The strain energy density W is computed using:(1)
    W = i = 1 N 2 μ i α i 2 ( λ ¯ 1 α i + λ ¯ 2 α i + λ ¯ 3 α i 3 ) + i = 1 N 1 D 1 ( J 1 ) 2 i

    with λ i being the ith principal stretch, J = λ 1 * λ 2 * λ 3 being the relative volume and λ ¯ = J 1 3 λ .

  5. The Bulk Modulus K is:
    If NU = 0,(2)
    K = 2 D 1
    If NU ≠ 0, then the value D 1 is modified to respect.(3)
    K = 2 ( 1 + v ) 3 ( 1 2 v ) G

    If NU = 0 and D 1 = 0, then μ = 0.475.

  6. The ground shear modulus is:(4)
    G = 1 N μ i
  7. This card is represented as a material in HyperMesh.