"Read From File"
"Read from File"
This method assumes that data in the appropriate format has been generated externally and saved in ASCII format data files.
Filename syntax
A separate file is required for each state, and its name is determined from the "root" filename supplied. This must be of the form
<name> nnn <.ext> Where:
| <name> | Is an arbitrary prefix |
For example a valid filename might be"nodal_1.dat" (decomposes
to <
nodal_
>, <
1
>,
<
.dat
>)
The actual number used in the "root" filename is not material, it must just be a digit from 0 - 9. |
| nnn | Is one or more digits. | |
| <.ext> | Is an arbitrary extension |
For each state the digit <nnn> is replaced with the number of the state, so in the example above D3PLOT would look for the file sequence:
nodal_1.dat for state #1, nodal_2.dat for state#2, and so on.
The number nnn can have up to 10 leading zeros, so both nodal_1.dat and nodal_0001.dat would be acceptable filenames, and the number of leading zeros does not have to be the same for each state.
If a file for a given state is not found then values of 0.0 will be used for that state.
File content and structure
In all files:- Blank lines are ignored.
- Lines starting with #, % or $ are treated as comment lines and are ignored.
- Input is not case-sensitive: any mixture of upper and lower case can be used.
- Numeric input is "free": no particular field width or column number is implied.
- Field separators may be spaces, tabs or commas.
- Each row of data must be on a single line.
- Maximum line width is 256 characters.
The formats of the various data types are as follows:
Scalar data |
||
| One of |
NODE SCALAR
SOLID SCALAR BEAM SCALAR SHELL SCALAR TSHELL SCALAR |
A new header can appear at any time to start a new data category. |
| Optionally: | DEFAULT <value> | A default of 0.0 is assumed if this line is not present |
| Optionally: |
SURFACE TOP
or
MIDDLE
or
BOTTOM
For models with fully integrated elements and data written at each on plan integration point (MAXINT -ve), the on plan point to read data into can be specified using the syntax:
SURFACE TOP
@<on plan>
or
MIDDLE@
<on plan>
or
BOTTOM
@<on plan>
|
Ignored for Node, Solid or Beam data. For shells the current surface is assumed unless a SURFACE or LAYER line is defined. The first on plan point is used if it is not defined. |
|
Followed by any
number of lines |
<label> <value>
<label> <value> |
If <label> is not found in the model the line is ignored. Entities which don't have a value line are given the default value. |
| Coordinate system | none is implied | Does not apply to scalar values. |
|
|
||
|
Example of a nodal scalar data file: NODE SCALAR
default 400.0
|
Example of a shell scalar data file: SHELL SCALAR default 10.0 surface top
1 1.23456e+02
|
|
Vector data |
||
| One of |
NODE VECTOR
BEAM VECTOR |
A new header can appear at any time to start a new data category. Vector data is not valid for solids, shells or thick shells |
| Optionally: | DEFAULT <3 values: x,y,z> | A default of (0.0, 0.0, 0.0) is assumed if this line is not present |
|
Followed by any
number of lines |
<label>
<3
values: x,y,z>
<label> <3 values: x,y,z> |
If <label> is not in the model found the line is ignored. Entities which don't have a value line are given the default vector value. |
| Coordinate system: |
Nodal data is assumed to be in the global cartesian system Beam data is assumed to be in the element local system |
These two conventions match the raw data in Ansys LS-DYNA database files. |
|
|
||
|
Example of a nodal vector data file: NODE VECTOR default 1.0 2.0 3.0
|
||
Tensor data |
|||||
| One of |
SOLID
SHELL TSHELL |
Followed
by one of |
TENSOR
TENSOR_UPPER TENSOR_LOWER |
TENSOR implies linear data order
(The tensor is implicitly symmetric) |
[xx, yy, zz, xy, yz, zx]
[xx, xy, xz, yx, yy, zz] [xx, yx, yy, zx, zy, zz] |
| Optionally: | DEFAULT <6 values> |
A default of [0.0, 0.0, 0.0, 0.0, 0.0, 0.0] is assumed if this line is not present If a default is supplied it must be in the order implied above. |
|||
| Optionally: |
SURFACE TOP
or
MIDDLE
or
BOTTOM
For models with fully integrated elements and data written at each on plan integration point (MAXINT -ve), the on plan point to read data into can be specified using the syntax:
SURFACE TOP
@<on plan>
or
MIDDLE@
<on plan>
or
BOTTOM
@<on plan>
|
Ignored for Solid data. For shells the current surface is assumed unless a SURFACE or LAYER line is defined. The first on plan point is used if it is not defined. |
|||
| Optionally one of |
GLOBAL
LOCAL_DYNA LOCAL_NASTRAN_2D LOCAL_NASTRAN_3D |
Default, and need not be specified, tensor data is normally assumed
to be global
|
|||
|
This option permits data to be defined externally in the element local coordinate system. It will be converted to global when read, and stored internally in the global system. The definitions of element local coordinate systems in DYNA and NASTRAN are not the same , so make sure that you specify the correct one for your data source in order to obtain the correct transformation back to the global system. A 2D tensor, the LOCAL_NASTRAN_2D case, reads only 3 columns of [xx, yy, xy] data, in that order, and is suitable for "plane stress" thin shell data. The "missing" 3D terms (yz, zx, zz) will be set to zero internally to create a full 3D local tensor, then the result will be converted to the global cartesian system as for the other local cases above. |
|||||
|
Followed by any
number of lines |
<label> <6 values>
<label> <6 values> |
If <label> is not found in the model the line is ignored. Data must be in the tensor order implied by the header above Entities which don't have a value line are given the default values. |
|||
| Coordinate system | The global cartesian system is assumed, but conversion from external local to internal global is possible via a LOCAL_ xxx option. | This matches the raw data in the Ansys LS-DYNA database | |||
|
Example of a shell tensor data file: SHELL TENSOR
Default 1.0 2.0 3.0 4.0 5.0 6.0
1 1.1567E+02 -3.9286E+01 -1.2514E-01 -1.2733E+01
3.8389E+00 -4.6773E+00
|
|
Example of a shell tensor data file that is ex-Nastran data defined
in the element local system.
SHELL TENSOR
Surface top
1 6.988275E+02 1.032284E+02
-1.468281E+02
|
Multiple headers are permitted in a file
A file can contain any number of data headers of the relevant type, for example a file for "Solid and Shell scalar data" can contain multiple headers for both solid and shell element types, for example the following file contains scalar data for both solid and shell elements:
|
SHELL SCALAR
1 1.23456e+02
SOLID SCALAR
1 3.45678e+02
|
File reading of a particular type of data will continue until either a new header is found or [end of file] is encountered.
If a header that does not match the type of data expected is encountered (for example the data component is NODE SCALAR, but a BEAM VECTOR header is encountered) then a warning message will be written and the mis-matched data will be skipped. Whilst this is not a fatal error, it is recommended that you do not mix different data types in the same file. This can cause confusion for other users, and could cause D3PLOT to perform slowly due to reading large amounts of unecessary data.