**ascii_file

Description

This parameter type allows an easy input of parameter data with an ASCII file. The use of ASCII allows simple generation of the table values, for example by using scripts. Just as for the binary file parameter type (see file), it allows mixed use of uniform parameter values, parameter values specified by a function and binary file records containing the values of the parameter field. Note: some command options are available only in Z-set version 8.4 or newer.

Syntax

**ascii_file param-name [ *node ] [ *ip ] [ *node_averaged ] [ *dtime ] [ *table_file tablefile name ] [ *cycle_conversion start  end  period ] [ *rec_size size ] \(~\,~\,\) time uniform value \(~\,~\,\) time function func; \(~\,~\,\) time file filename  record  column

**ascii_file

takes param-name (a character string) as argument for specifying the name of the parameter. This name will be used to reference the parameter values elsewhere in the problem.

*node

specifies that the parameter is applied at nodes. This is the default.

*ip

specifies that the parameter is applied at integration points.

*node_averaged

specifies that the parameter is applied at nodes, the nodal values then averaged, so one value of parameter for each element is obtained.

dtime

converts the absolute time values given in the table below to time increments.

*table_file

takes as argument the character string table_file name as the name of the file from which the table containing the list of times or time increments with their associated parameter types (uniform, function or file) can be read. This is an alternative to directly specifying the table here (see below), and can be useful for automatic table generation by scripts.

*rec_size

specifies the size of each data entry record. For FEA problems and *node type parameters, this is the number of nodes (can be found in the problem.geof file, or in Zmaster). For *ip type parameters, this is the number of integration points.

*cycle_conversion

real values for start time of cycles, end time, and cycle period are to be input. This command generates a variable time which can be used in function records to define the time.

The table specifying parameter values contain the following elements:

time

a time value for the given parameter data. parameter values during the calculation will be found using linear interpolation between given times. Do not forget to specify a value for time = 0.0. If the *dtime command is given, the time value becomes a time increment value. The time values may also be specified as a function. This is especially useful in conjunction with the *cycle_conversion command (see the example given in the ***parameter **file section on file ).

value

a uniform parameter value.

func

a function specified in the standard Z-set manner. Do not forget the ; at the end.

filename

name of the ASCII file to use. Different files can be given for different time values.

record

record number in the file. These are numbered from zero (0 is the first record).

column

column number for the data. Column number starts with 1.

Example

The following is an example of a variable Young’s modulus imposed with an ascii_file parameter.

***parameter
 **ascii_file yng
  *rec_size 20
  *node
   0.0   file param_as_young.inp 0 2
   1.e20 file param_as_young.inp 1 2

The file param_as_young.inp of the example above might look like this :

 1.   200000.0   % first line in file (rec 0)
 2.   195000.
 3.   198000.
...
 20.  199000.    % end of 0th rec
 1.   220000.0   % start 1st record
...

The parameter is then applied in the constitutive law:

***behavior gen_evp
 **elasticity isotropic
   young = yng      % young assigned to field parameter
   poisson 0.25
 **save_coefficients
   young

If the parameter is to be applied at integration points, the data file must look like this :

 1.   200000.
 1.   195000.
 1.   198000.
 2.   211000.
 2.   205000.
 2.   203000.
...

where the fist columns indicates the element number. In this example, the elements have 3 integration points. rec_size hes to be set to the total number of integration points.