# 15.20. NLVE 3D Orthotropic Model

    BEGIN PARAMETERS FOR MODEL NLVE_3D_ORTHOTROPIC
      #
      # Elastic constants
      #
      YOUNGS MODULUS = <real>
      POISSONS RATIO = <real>
      SHEAR MODULUS  = <real>
      BULK MODULUS   = <real>
      LAMBDA         = <real>
      TWO MU         = <real>
      #
      # Material coordinates system definition
      #
      COORDINATE SYSTEM             = <string> coordinate_system_name
      DIRECTION FOR ROTATION        = <real> 1|2|3
      ALPHA                         = <real> (degrees)
      SECOND DIRECTION FOR ROTATION = <real> 1|2|3
      SECOND ALPHA                  = <real> (degrees)
      #
      #
      #
      FICTITIOUS LOGA FUNCTION = <string>fict_loga_function_name
      FICTITIOUS LOGA SCALE FACTOR = <real>fict_loga_scale_factor
      #
      # In each of the five "PRONY" command lines and in
      # the RELAX TIME command line, the value of i can be from
      # 1 through 30
      #
      1PSI PRONY <integer>i = <real>psi1_i
      2PSI PRONY <integer>i = <real>psi2_i
      3PSI PRONY <integer>i = <real>psi3_i
      4PSI PRONY <integer>i = <real>psi4_i
      5PSI PRONY <integer>i = <real>psi5_i
      RELAX TIME <integer>i = <real>tau_i
      REFERENCE TEMP = <real>tref
      REFERENCE DENSITY = <real>rhoref
      WLF C1 = <real>wlf_c1
      WLF C2 = <real>wlf_c2
      B SHIFT CONSTANT = <real>b_shift
      SHIFT REF VALUE = <real>shift_ref
      WWBETA 1PSI = <real>wwb_1psi
      WWTAU 1PSI = <real>wwt_1psi
      WWBETA 2PSI = <real>wwb_2psi
      WWTAU 2PSI = <real>wwt_2psi
      WWBETA 3PSI = <real>wwb_3psi
      WWTAU 3PSI = <real>wwt_3psi
      WWBETA 4PSI = <real>wwb_4psi
      WWTAU 4PSI = <real>wwt_4psi
      WWBETA 5PSI = <real>wwb_5psi
      WWTAU 5PSI = <real>wwt_5psi
      DOUBLE INTEG FACTOR = <real>dble_int_fac
      REF RUBBERY HCAPACITY = <real>hcapr
      REF GLASSY HCAPACITY = <real>hcapg
      GLASS TRANSITION TEM = <real>tg
      REF GLASSY C11 = <real>c11g
      REF RUBBERY C11 = <real>c11r
      REF GLASSY C22 = <real>c22g
      REF RUBBERY C22 = <real>c22r
      REF GLASSY C33 = <real>c33g
      REF RUBBERY C33 = <real>c33r
      REF GLASSY C12 = <real>c12g
      REF RUBBERY C12 = <real>c12r
      REF GLASSY C13 = <real>c13g
      REF RUBBERY C13 = <real>c13r
      REF GLASSY C23 = <real>c23g
      REF RUBBERY C23 = <real>c23r
      REF GLASSY C44 = <real>c44g
      REF RUBBERY C44 = <real>c44r
      REF GLASSY C55 = <real>c55g
      REF RUBBERY C55 = <real>c55r
      REF GLASSY C66 = <real>c66g
      REF RUBBERY C66 = <real>c66r
      REF GLASSY CTE1 = <real>cte1g
      REF RUBBERY CTE1 = <real>cte1r
      REF GLASSY CTE2 = <real>cte2g
      REF RUBBERY CTE2 = <real>cte2r
      REF GLASSY CTE3 = <real>cte3g
      REF RUBBERY CTE3 = <real>cte3r
      LINEAR VISCO TEST = <real>lvt
      T DERIV GLASSY C11 = <real>dc11gdT
      T DERIV RUBBERY C11 = <real>dc11rdT
      T DERIV GLASSY C22 = <real>dc22gdT
      T DERIV RUBBERY C22 = <real>dc22rdT
      T DERIV GLASSY C33 = <real>dc33gdT
      T DERIV RUBBERY C33 = <real>dc33rdT
      T DERIV GLASSY C12 = <real>dc12gdT
      T DERIV RUBBERY C12 = <real>dc12rdT
      T DERIV GLASSY C13 = <real>dc13gdT
      T DERIV RUBBERY C13 = <real>dc13rdT
      T DERIV GLASSY C23 = <real>dc23gdT
      T DERIV RUBBERY C23 = <real>dc23rdT
      T DERIV GLASSY C44 = <real>dc44gdT
      T DERIV RUBBERY C44 = <real>dc44rdT
      T DERIV GLASSY C55 = <real>dc55gdT
      T DERIV RUBBERY C55 = <real>dc55rdT
      T DERIV GLASSY C66 = <real>dc66gdT
      T DERIV RUBBERY C66 = <real>dc66rdT
      T DERIV GLASSY CTE1 = <real>dcte1gdT
      T DERIV RUBBERY CTE1 = <real>dcte1rdT
      T DERIV GLASSY CTE2 = <real>dcte2gdT
      T DERIV RUBBERY CTE2 = <real>dcte2rdT
      T DERIV GLASSY CTE3 = <real>dcte3gdT
      T DERIV RUBBERY CTE3 = <real>dcte3rdT
      T DERIV GLASSY HCAPACITY = <real>dhcapgdT
      T DERIV RUBBERY HCAPACITY = <real>dhcaprdT
      REF PSIC = <real>psic_ref
      T DERIV PSIC = <real>dpsicdT
      T 2DERIV PSIC = <real>d2psicdT2
      PSI EQ 2T = <real>psitt
      PSI EQ 3T = <real>psittt
      PSI EQ 4T = <real>psitttt
      PSI EQ XX 11 = <real>psiXX11
      PSI EQ XX 22 = <real>psiXX22
      PSI EQ XX 33 = <real>psiXX33
      PSI EQ XX 12 = <real>psiXX12
      PSI EQ XX 13 = <real>psiXX13
      PSI EQ XX 23 = <real>psiXX23
      PSI EQ XX 44 = <real>psiXX44
      PSI EQ XX 55 = <real>psiXX55
      PSI EQ XX 66 = <real>psiXX66
      PSI EQ XXT 11 = <real>psiXXT11
      PSI EQ XXT 22 = <real>psiXXT22
      PSI EQ XXT 33 = <real>psiXXT33
      PSI EQ XXT 12 = <real>psiXXT12
      PSI EQ XXT 13 = <real>psiXXT13
      PSI EQ XXT 23 = <real>psiXXT23
      PSI EQ XXT 44 = <real>psiXXT44
      PSI EQ XXT 55 = <real>psiXXT55
      PSI EQ XXT 66 = <real>psiXXT66
      PSI EQ XT 1 = <real>psiXT1
      PSI EQ XT 2 = <real>psiXT2
      PSI EQ XT 3 = <real>psiXT3
      PSI EQ XTT 1 = <real>psiXTT1
      PSI EQ XTT 2 = <real>psiXTT2
      PSI EQ XTT 3 = <real>psiXTT3
      REF PSIA 11 = <real>psiA11
      REF PSIA 22 = <real>psiA22
      REF PSIA 33 = <real>psiA33
      REF PSIA 12 = <real>psiA12
      REF PSIA 13 = <real>psiA13
      REF PSIA 23 = <real>psiA23
      REF PSIA 44 = <real>psiA44
      REF PSIA 55 = <real>psiA55
      REF PSIA 66 = <real>psiA66
      T DERIV PSIA 11 = <real>dpsiA11dT
      T DERIV PSIA 22 = <real>dpsiA22dT
      T DERIV PSIA 33 = <real>dpsiA33dT
      T DERIV PSIA 12 = <real>dpsiA12dT
      T DERIV PSIA 13 = <real>dpsiA13dT
      T DERIV PSIA 23 = <real>dpsiA23dT
      T DERIV PSIA 44 = <real>dpsiA44dT
      T DERIV PSIA 55 = <real>dpsiA55dT
      T DERIV PSIA 66 = <real>dpsiA66dT
      REF PSIB 1     = <real> psiB1
      REF PSIB 2     = <real> psiB2
      REF PSIB 3     = <real> psiB3
      T DERIV PSIB 1 = <real> dpsiB1dT
      T DERIV PSIB 2 = <real> dpsiB2dT
      T DERIV PSIB 3 = <real> dpsiB3dT
      PSI POT TT     = <real> psipotTT
      PSI POT TTT    = <real> psipotTTT
      PSI POT TTTT   = <real> psipotTTTT
      PSI POT XT 1   = <real> psipotXT1
      PSI POT XT 2   = <real> psipotXT2
      PSI POT XT 3   = <real> psipotXT3
      PSI POT XTT 1  = <real> psipotXTT1
      PSI POT XTT 2  = <real> psipotXTT2
      PSI POT XTT 3  = <real> psipotXTT3
      PSI POT XXT 11 = <real> psipotXXT11
      PSI POT XXT 22 = <real> psipotXXT22
      PSI POT XXT 33 = <real> psipotXXT33
      PSI POT XXT 12 = <real> psipotXXT12
      PSI POT XXT 13 = <real> psipotXXT13
      PSI POT XXT 23 = <real> psipotXXT23
      PSI POT XXT 44 = <real> psipotXXT44
      PSI POT XXT 55 = <real> psipotXXT55
      PSI POT XXT 66 = <real> psipotXXT66
    END [PARAMETERS FOR MODEL NLVE_3D_ORTHOTROPIC]

The NLVE three-dimensional orthotropic model is a nonlinear viscoelastic orthotropic continuum model that describes the behavior of fiber-reinforced polymer-matrix composites. In addition to being able to model the linear elastic and linear viscoelastic behaviors of such composites, it also can capture both “weak” and “strong” nonlinear viscoelastic effects such as stress dependence of the creep compliance and viscoelastic yielding. This model can be used in both Presto and Adagio.

Because the NLVE model is still under active development and also because it has an extensive list of command lines, we have not followed the typical approach in documenting this model.