6.0       INITIAL NODAL KINEMATIC CONDITION DATA

 

6.1       Nodal Initial Displacement Data

 

INITIAL_D0

 

 

            INITIAL_D0      generation_type = type ,  etc...

                  n,   numgp,   ( d(i, n),  i = 1 , ndof )

                  < etc..., terminate with a blank record >

 

 

Create the list of initial displacements.  Two options are available.  The initial displacements may be read in directly as a list (optionally from another file), or may be generated.

 

Note    Variable Name                 Type        Default      Description

 

            Generation_type                 list            [*]          Generation case

               list

               Cartesian

 

            Variable                                list          [*]          Nodal unknowns selection:

               all                                                                       all degrees of freedom

               solid_displacement                                            solid displacement

               solid_displacement_and_rotation                      solid displacement and rotation

               fluid_velocity                                                     fluid velocity

               temperature                                                        temperature

               pressure                                                              pressure

               potential                                                             potential

               electric_potential                                                electric potential

               scalar_transport                                                  scalar transport

               level_set                                                             level set

               stream_fct                                                          stream function

               solid_displacement_and_fluid_velocity            porous continuum

               solid_displacement_and_fluid_pressure            porous continuum

               solid_displacement_and_temperature                     thermo-solid continuum

               mesh_motion                                                      ALE mesh motion

 

            File_name                         string       [none]       File name (optional).  Name must

                                                                                            be enclosed in quotation marks.

 

• No Generation (List) Case

            Initial nodal displacements must follow in the form:

               < Node_number, Displacement_X, Displacement_Y, Displacement_Z, etc...>

               < etc..., terminate with a blank record >

 

• Generation Case

            Initial Nodal Displacements Generation Data must follow.

               < terminate with a blank record >

 

 

 

 

EXAMPLE

         Initial_D0  /

            file_name = "initial_d0_file"                        # read displacements from file:  initial_d0_file

 

EXAMPLE

         Initial_D0  /

            generation_type = cartesian                         # Select generation option

            Initial Nodal Displacements Generation Data follow

 

 

6.1.1       Nodal Initial Displacement Generation Data

 

 

Note          Variable           Default                  Description

 

(1)                    N                   [0]                      Node number  1 and  NUMNP

 

(2)              NUMGP             [0]                      Number of generation points

                                                                           = 0, no generation

                                                                           ≠ 0, generate data

 

(3)               D(1, N)             [0.0]                    Degree of freedom 1 initial displacement

 

                   D(2, N)             [0.0]                    Degree of freedom 2 initial displacement

                         .                      .                                       .

                       etc.                   .                                       .

                         .                      .                                       .

               D(NDOF, N)        [0.0]                    Degree of freedom NDOF initial displacement

 

 

Notes/

(1)        Initial displacement data must be included for each node subjected to non-zero

initial displacement.  Terminate with a blank record.

 

(2)        If NUMGP is greater than zero, this records initiates an isoparametric data generation sequence.  The scheme used is the same as the one used for coordinate generation described previously in Chapter 4. Records 2 to NUMGP of the sequence define the initial displacements of the additional generation points (see Section 6.2).  The final record of the sequence defines the nodal increment information, and is identical to the one used for coordinate generation (see Section 4.3).  After the generation sequence is completed, additional nodal initial displacement records, or generation sequences, may follow.

 

            The generation may be performed along a line, over a surface, or over a volume.  A description of these options is given below.

 

A.  Generation Along a Line

 

            Generation of data  along a line may be performed using 2, or 3 generation points (see Figure 6.3), and the physical space (D-space) may be 1, 2, or 3 dimensional.

 

            If NUMGP = 2, linear interpolation takes place with respect to -space. If the values are equally spaced in D-space, then the variation will also be linear in D-space. Otherwise a nonlinear variation will be induced by the unequal values spacing.

 

 

            If NUMGP = 3, quadratic interpolation is performed with respect to  space. Note that the third generation point does not generally coincide with a nodal point. The variation of data may be determined from the following mapping:

 

 

where  is the location of node number A in -space (recall that the nodes are assumed to be placed at equal intervals in -space); D1g, D2g  and D3g are the displacement data assigned to the three generation points (i.e.,  = -1, +1, and 0, resp.); and DA is the generated displacement data at node A.

 

The case in which NUMGP = 2, may be deduced from the case NUMGP = 3 by setting D3g = (D1g + D2g)/2

 

B.  Generation Over a Surface

 

            Generation of data may be performed using 4, or 8 generation points.  The generation points and nodal patterns are the same as in coordinate generation (see Figure 4.1.3).

 

            In the case NUMGP = 4, bilinear interpolation is performed; for NUMGP = 8, biquadratic "serendipity" interpolation is performed. Note that generation points 5-8 do not in general coincide with nodal points.

 

C.  Generation Over a Volume

 

            Generation of data over a brick-shaped volume may be performed using 8, or 20 generation points. The generation points and nodal patterns are the same as for coordinate generation (see Figure 4.1.4).

 

            If NUMGP = 8, trilinear interpolation is employed; if NUMGP = 20, triquadratic "serendipity" interpolation is employed. Note that generation points 9-20 do not in general coincide with nodal points.

 

(3)        The elements of the array D(NDOF,NUMNP) are initialized to zero.  If the initial displacements of node N are input and/or generated more than one time, the last values take priority.

 

 

6.1.2       Generation Point Initial Displacement Data (NUMGP-1)

 

            The initial displacements of each generation point are defined by a generation point initial displacement record.  The records must be read in order (J = 2, 3,...,NUMGP) following the nodal initial displacement record which initiated the generation sequence (J = 1).  A nodal increments record (see Section 6.1.3), which completes the sequence, must follow the last generation point record (J = NUMGP).

 

Note    Variable              Default         Description

 

                M                       [0]             Node number

 

            MGEN                   [0]             Generation parameter

= 0, initial displacements of the Jth generation point are input on this card; M is ignored

= 1, initial displacements of the Jth generation point are set equal to initial displacements of node M which was previously defined; initial displacements on this card are ignored

 

         TEMP(1,J)               [0.0]           Degree of freedom 1 initial displacement of
                                                               generation point J

 

         TEMP(2,J)               [0.0]           Degree of freedom 2 initial displacement of
                                                                generation point J

                  .                          .                                          .

               etc.                        .                                          .

                  .                          .                                          .

     TEMP(NDOF,J)          [0.0]           Degree of freedom NDOF initial displacement
                                                               of generation point J

 

 

 

 

6.1.3       Nodal Increments Data

 

 

Note    Variable              Default         Description

 

           NINC(1)                 [0]             Number of nodal increments for direction 1

 

            INC(1)                   [0]             Node number increment for direction 1

 

(1)      NINC(2)                 [0]             Number of nodal increments for direction 2

 

            INC(2)                   [0]             Node number increment for increment 2

 

(1)      NINC(3)                 [0]             Number of nodal increments for direction 3

 

            INC(3)                   [0]             Node number increment for direction 3

 

 

Notes/

(1)        Each option is assigned an option code (IOPT) as follows:

 

                                            IOPT                    Option

                                               1                       Generation along a line

                                               2                       Generation over a surface

                                               3                       Generation over a volume

 

            IOPT is determined by the following logic:

           

                                                IOPT = 3

                                                IF(NINC(3) = 0)   IOPT = 2

                                                IF(NINC(2) = 0)   IOPT = 1

 

 

 

6.2       Nodal Initial Velocity Data

 

INITIAL_V0

 

 

            INITIAL_V0           generation_type = type ,  etc...

                  n,     numgp,     ( v(i, n), i = 1 , ndof )

                  < etc..., terminate with a blank record >

 

 

Create the list of initial nodal velocities.  Two options are available: the initial velocities may be read in directly as a list (optionally from another file), or may be generated.  Use same sequence as for nodal initial displacement generation data.

 

 

 

 

Notes . .

 

 

 

 

6.3       Background Nodal Field Data

 

BACKGROUND_NODAL_FIELD

 

 

            BACKGROUND_NODAL_FIELD    generation_type = type ,  etc...

                  n,   numgp,   ( v(i, n), i = 1 , ncomp )

                  < etc..., terminate with a blank record >

 

 

Create a background field of nodal velocities.  Two options are available:  the velocities may be read in directly as a list (optionally from another file), or may be generated.  Use same sequence as for nodal initial displacement generation data.

 

 

 

 

 

Figure 6.3  Displacement / Velocity Vector Generation