*INITIAL CONDITIONS

Keyword type: model definition

This option is used to define initial temperatures, initial velocities, initial stresses and initial plastic strains. There are two parameters: TYPE and USER. The parameter TYPE is required. It can take the following values:

For shell elements TYPE=TEMPERATURE can be used to define an initial temperature gradient in addition to an initial temperature. The temperature applies to nodes in the reference surface, the gradient acts in normal direction. For beam elements two gradients can be defined: one in 1-direction and one in 2-direction. Default for the gradients is zero.

The plastic strain components defined with this option are subtracted from the strain components computed from the displacement field. If thermal strains are relevant they are additionally subtracted. The resulting strain is used to compute the stress and tangent stiffness matrix using the appropriate constitutive equations.

The parameter USER can only be used if TYPE=STRESS or TYPE=SOLUTION is specified. In that case, the user must define the initial stresses or internal variables by user routine sigini.f or sdvini.f, respectively.

Please note that vector and tensor quantities have to be provided in the GLOBAL (rectangular) coordinate system, no matter whether an *ORIENTATION card or *TRANSFORM card applies to the corresponding element or node, respectively.


First line:


Following line for TYPE=DISPLACEMENT:


Following line for TYPE=PLASTIC STRAIN:

Repeat this line if needed. The strain components should be given as Lagrange strain components for nonlinear calculations and linearized strain components for linear computations.


Following line for TYPE=PRESSURE, TYPE=TOTAL PRESSURE or TYPE=MASS FLOW:

Repeat this line if needed.


Following line for TYPE=SOLUTION if USER is not specified:

Repeat this line if needed. Each line should contain exactly 8 entries (including the element and integration point number in the first line), except for the last line, which can contain less. For instance, if the number of internal variables is 11, the first line contains 6 and the second 5. If you have 20 internal variables, the first line contains 6, the second 8 and the third 6. The number of internal variables must be specified by using the *DEPVAR card.


There is no line following the first one for TYPE=SOLUTION,USER.


Following line for TYPE=STRESS if USER is not specified:

Repeat this line if needed. The stress components should be given in the form of second Piola-Kirchhoff stresses.

There is no line following the first one for TYPE=STRESS,USER.


Following line for TYPE=TEMPERATURE:

Repeat this line if needed.


Following line for TYPE=VELOCITY or TYPE=FLUID VELOCITY:

Examples:

*INITIAL CONDITIONS,TYPE=TEMPERATURE
Nall,273.

assigns the initial temperature T=273. to all nodes in (node) file Nall.

*INITIAL CONDITIONS,TYPE=VELOCITY
18,2,3.15

assigns the initial velocity 3.15 to degree of freedom 2 of node 18.


Example files: beam20t, beamnlt, beamt3, resstress1, resstress2, resstress3, inistrain.