Nastran creep material properties

The following tables provide information about the options you should use to define the various creep laws supported by Nastran. These options are available on the Creep page in the Materials dialog box.

For detailed information about defining creep material properties, see your Nastran documentation.

Creep law type 111

Creep Strain = A * (1–exp^(-R*time)) + (K * time)

Where A = C1, R = C2, and K = C3 in the dialog box.

Type	Coefficients	Notes
O.R.N.L viscoplastic material	C1 = a * SIGMA^bC2 = c * exp^(d * SIGMA)C3 = e * [sinh (f * SIGMA)]^gEnter the a – g coefficients in the dialog box.	This combination of inputs corresponds to the CREEP bulk entry with FORM=CRLAW and TYPE=111.Type 111 is supported in SOL 106 Nonlinear Statics solutions.

Creep law type 112

Creep Strain = A * (1–exp^(-R*time)) + (K * time)

Where A = C1, R = C2, and K = C3 in the dialog box.

Type	Coefficients	Notes
O.R.N.L viscoplastic material	C1 = a * SIGMA^bC2 = c * exp^(d * SIGMA)C3 = e * exp^(f * SIGMA)Enter the a – f coefficients in the dialog box.	This combination of inputs corresponds to the CREEP bulk entry with FORM=CRLAW and TYPE=112.Type 112 is supported in SOL 106 Nonlinear Statics solutions.

Creep law type 121

Creep Strain = A * (1–exp^(-R*time)) + (K * time)

Where A = C1, R = C2, and K = C3 in the dialog box.

Type	Coefficients	Notes
O.R.N.L viscoplastic material	C1 = a * SIGMA^bC2 = c * SIGMA^dC3 = e * [sinh (f * SIGMA) ]^gEnter the a – g coefficients in the dialog box.	This combination of inputs corresponds to the CREEP bulk entry with FORM=CRLAW and TYPE=121.Type 121 is supported in SOL 106 Nonlinear Statics solutions.

Creep law type 122

Creep Strain = A * (1–exp^(-R*time)) + (K * time)

Where A = C1, R = C2, and K = C3 in the dialog box.

Type	Coefficients	Notes
O.R.N.L viscoplastic material	C1 = a * SIGMA^bC2 = c * exp^(d * SIGMA)C3 = e * exp^(f * SIGMA)Enter the a – f coefficients in the dialog box.	This combination of inputs corresponds to the CREEP bulk entry with FORM=CRLAW and TYPE=122.Type 122 is supported in SOL 106 Nonlinear Statics solutions.

Creep law type 211

Creep Strain = A * (1–exp^(-R*time)) + (K * time)

Where A = C1, R = C2, and K = C3 in the dialog box.

Type	Coefficients	Notes
O.R.N.L viscoplastic material	C1 = a * exp^(b * SIGMA)C2 = c * exp^(d * SIGMA)C3 = e * [sinh (f * SIGMA) ]^gEnter the a – g coefficients in the dialog box.	This combination of inputs corresponds to the CREEP bulk entry with FORM=CRLAW and TYPE=211.Type 211 is supported in SOL 106 Nonlinear Statics solutions.

Creep law type 212

Creep Strain = A * (1–exp^(-R*time)) + (K * time)

Where A = C1, R = C2, and K = C3 in the dialog box.

Type	Coefficients	Notes
O.R.N.L viscoplastic material	C1 = a * exp^(b * SIGMA)C2 = c * exp^(d * SIGMA)C3 = e * exp^(f * SIGMA)Enter the a – f coefficients in the dialog box.	This combination of inputs corresponds to the CREEP bulk entry with FORM=CRLAW and TYPE=212.Type 212 is supported in SOL 106 Nonlinear Statics solutions.

Creep law type 221

Creep Strain = A * (1–exp^(-R*time)) + (K * time)

Where A = C1, R = C2, and K = C3 in the dialog box.

Type	Coefficients	Notes
O.R.N.L viscoplastic material	C1 = a * exp^(b * SIGMA)C2 = c * exp^(d * SIGMA)C3 = e * [sinh (f * SIGMA) ]^gEnter the a – g coefficients in the dialog box.	This combination of inputs corresponds to the CREEP bulk entry with FORM=CRLAW and TYPE=221.Type 221 is supported in SOL 106 Nonlinear Statics solutions.

Creep law type 222

Creep Strain = A * (1–exp^(-R*time)) + (K * time)

Where A = C1, R = C2, and K = C3 in the dialog box.

Type	Coefficients	Notes
O.R.N.L viscoplastic material	C1 = a * exp^(b * SIGMA)C2 = c * exp^(d * SIGMA)C3 = e * exp^(f * SIGMA)Enter the a – f coefficients in the dialog box.	This combination of inputs corresponds to the CREEP bulk entry with FORM=CRLAW and TYPE=222.Type 222 is supported in SOL 601,106 Advanced Nonlinear Statics solutions.

Creep law type 300

Creep Strain = A * (SIGMA^n) * (time^m)

Type	Coefficients	Notes
Time Hardening (Norton-Bailey) Power Law	Enter the A, n, and m coefficients in the dialog box.The coefficients in the dialog box correspond to the following terms in the Nastran equation:n = bm = d	This combination of inputs corresponds to the CREEP bulk entry with FORM=CRLAW and TYPE=300.Type 300 is supported in SOL 601,106 Advanced Nonlinear Statics solutions.

Creep law type 301

Type	Coefficients	Notes
Temperature-Dependent Time Hardening (Norton-Bailey) Power Law	The A, B, and D coefficients are used to define the Norton-Bailey creep model as follows:Enter the A, B, and D coefficients of this creep model in the Constant Multiplier (a), SIGMA Exponent (b), and Hardening Exponent (d) boxes.To define creep at a single temperature, enter real values for the coefficients.To define creep as temperature dependent, define a table field for the coefficients. The table corresponds to the TABLEM1 bulk entry.	This property corresponds to the MATCRP bulk entry, which is an alternate method for selecting the Norton-Bailey creep model. This option lets you define the coefficients of the power law equation as either constant or temperature dependent.Type 301 is supported in SOL 401 Multi-Step Nonlinear, SOL 402 Multi-Step Nonlinear Kinematics, and SOL 601,106 Advanced Nonlinear solutions.For Simcenter 3D Multiphysics, you can turn off creep effects at the solution level and subcase level. In the Solution dialog box, the Material Nonlinearity option must be selected for plasticity or creep effects to exist anywhere in the solution. If the Material Nonlinearity option is selected, you can separately control creep and plasticity in each step through the Nonlinear Control Parameters.

General tabular input creep or linear viscoelastic behavior

Type	Parameters	Notes
Kelvin-Maxwell, uniaxial creep-recovery test, Tabular Input	Define table fields to represent primary spring (Kp), primary damping (Cp), and secondary damping (Cs) curves.Tabular values (Xi, Yi) correspond to: Kp: (SIGMAi, Kpi)Cp: (SIGMAi, Cpi)Cs: (SIGMAi, Csi)	This combination of inputs corresponds to the CREEP bulk entry with FORM=TABLE.The creep model parameters must have positive values.For linear viscoelastic materials, parameters Kp, Cp, and Cs are constant and two values of SIGMAi must be specified for the same value of Kpi, Cpi, and Csi.This type of creep definition is supported in SOL 106 Nonlinear Statics solutions.

Creep laws for visco-plastic materials

These creep definitions are supported in SOL 401 Multi-Step Nonlinear and SOL 402 Multi-Step Nonlinear Kinematics.

Type	Parameters	Notes
Strain Hardening Creep (MVPLAS/Law STRNHARD)	{{\dot \varepsilon }_{cr}} = {C_1}{\sigma ^{{C_2}}}\varepsilon _{cr}^{{C_3}}{e^{ - {C_4}/T}}	This combination of inputs corresponds to the MVPLAS bulk entry.The coefficients can be real values, or they can be integers to point to tables for temperature dependence.
Norton Creep (MVPLAS/Law NORTON)	{{\dot \varepsilon }_{cr}} = {C_1}{\sigma ^{{C_2}}}{e^{ - {C_4}/T}}
Generalized Garofalo Creep (MVPLAS/Law GENGAROF)	{{\dot \varepsilon }_{cr}} = {C_1}{\left[ {\sinh \left( {{C_2}\sigma } \right)} \right]^{{C_3}}}{e^{ - {C_4}/T}}
Norton-Bailey in Time Hardening Creep (MVPLAS/Law TIMEHARD)	{{\dot \varepsilon }_{cr}} = {A D}{\sigma ^{{B}}}{t ^{{D-1}}}
User Creep (MVPLAS/Law USER + MUCRP on Bulk Data user defined text)	Dependent on the creep model you create.	For more information, see MUCRP.

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