Running the Interface

  The interface will only produce an input file if all or part of the model contains a mesh. The interface may be run using the FEMGEN command 'UTILITY WRITE DYNA filename'. The file name is optional and the default name is 'modelname.anl'. When the user supplies a file name with no extension, an extension (by default '.anl') will be automatically added. LLNL DYNA users should supply a four character file name with no extension, OASYS users should supply a file name with the extension '.inf' for the fixed format and with the extension '.key' for the keyword format. Alternatively, the required file extension can be defined using the resource Femsys.femgen.FileExtension.dyna, refer to the 'femsys.ini' file provided with the FEMGV installation (see also example in section 1.8).

There will be a pause whilst the interface gathers information on the model (this can be significant for large models) and the user will then be prompted for information relating to analysis time and result output frequency. For each question the user can use the enter/return key to accept the displayed default or enter a new value. At any point in the question and answer session the user may type '/' to return to the first question. Typing '/' in response to the first question will terminate the program. The user will be prompted with the following questions.

           
ENTER TERMINATION TIME (0.1) >

This user should enter the duration of the analysis in seconds.

           
NUMBER OF TIME STEPS FOR DEFAULT STEP TIME: 50000
ENTER TIME STEP SIZE ( 0.2E-06) >

The default step time is derived by the interface from material data and the minimum element edge length found in the model. The time step used must be sufficiently small such that a stress wave (which propagates at the speed of sound in the material) cannot traverse more than one element in one time step. The user may enter a value of zero in order to get DYNA3D to calculate the step time automatically. Appendix A gives details of how the default step time is calculated.

           
ENTER NUMBER OF PLOT STATES REQUIRED (MAX 99) (   20) >

The user should enter the number of states (equally spaced through the analysis) which are required for visualisation of the completed analysis.

           
ENTER NUMBER OF HISTORY STATES REQUIRED ( 2000) >

The user should enter the number of states (equally spaced through the analysis) which are required for graphing result values only. The frequency of this sort of output is usually set to be much higher than for the plot states and is generally restricted to certain key areas of the model. The nodes and/or elements for which history state data is produced are defined via node and element history blocks (see Chapter 7).

           
ENTER NUMBER OF RESTART FILE WRITES (5) >

The user should enter the number of states (equally spaced through the analysis) at which the complete model state is saved to a file from which the analysis can be resumed. A separate permanent file is created for each state.

DYNA3D also produces a version of the above file which is overwritten each time a new state is output. The rate at which this is done is set by the interface to be twice that of the permanent restart files.