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CHAPTER 3 - INPUT DEFINITION

CHAPTER 3 - INPUT DEFINITION. CONTENTS. MSC.Dytran Documentation Data Input Format of the Input MSC.Nastran Style Input File Management Section, Executive Control and Case Control Format Bulk Data Format Bulk Data Input Format Differences from MSC.Nastran. MSC.Dytran USER’S MANUAL.

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CHAPTER 3 - INPUT DEFINITION

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  1. CHAPTER 3 - INPUT DEFINITION

  2. CONTENTS • MSC.Dytran Documentation • Data Input • Format of the Input • MSC.Nastran Style Input • File Management Section, Executive Control and Case Control Format • Bulk Data Format • Bulk Data Input Format • Differences from MSC.Nastran

  3. MSC.Dytran USER’S MANUAL • 1 –Online Documentation • Available in pdf-format in MSC.Dytran Explorer • 2 –Hardcopy • Available in 2 volumes

  4. MSC.Dytran User’s Manual • Volume 1 • Section 1 - Introduction • Gives an overview of MSC.Dytran and its applicability, as well as a description of the explicit method of time integration and the Lagrange and Euler processors. • Section 2 - Modeling • Describes all the features of MSC.Dytran and what they can be used to model. The entry used to define the features is listed. Section 2 covers all of the capabilities of MSC/DYTRAN, both Lagrange and Euler. • Section 3 - Running the Analysis • The process of running the analysis is described from modeling to results post-processing. This section describes the commands necessary to run, restart and rezone the analysis and the files produced by MSC.Dytran. The use of user subroutines is also explained.

  5. MSC.Dytran User’s Manual (Cont’d) • Volume 2 • Section 4 - Input Data • This section is essentially a reference section. The format of each entry is described; the contents of each field, the type of data in it and the default values assumed if it is left blank. There are five main subsections: • FMSExecutive Control Case Control Bulk Data Parameter Values • Section 5 - Diagnostic Messages • Format of all the error and warning messages issued by MSC/DYTRAN. • Section 6 - References

  6. MSC.Dytran User’s Manual (Cont’d) • Appendix A - Using XDYTRAN • Describes how to use XDYTRAN, a UNIX based GUI to launch MSC.Dytran runs and to create customized executables. • Appendix B - Using XDEXTR • Describes how to XDEXTR, a UNIX based GUI that translates result s in the archive and time history files into various third party import file formats. • Appendix C – MSC.Dytran and Parallel Processing • Appendix D - Using ATB • Describes how to use MSC.Dytran in conjunction with ATB (Articulated Total Body) for occupant modeling. • Appendix E - Using MSC.Dytran with TNO/MADYMO • Describes how to use MSC.Dytran in conjunction with TNO/MADYMO to solve problems involving the interactions of occupants with deformable components. • Appendix F - Example Input Data • Appendix G - Using USA • Describes how to use the MSC.Dytran in conjunction with USA (Underwater Shock Analysis) code by DeRuntz et al.

  7. DATA INPUT • Input FileMSC.Dytran is designed to run in batch mode. All the data required for a job is provided in an input file, either created using an editor, or more often, created by a modeling package or preprocessor. • The input file is compatible with that for MSC.Nastran and consists of four main sections: • FMS • Executive Control • Case Control • Bulk Data • The input file is the same regardless of the type of computer you are using. The file is in ASCII format, so it can be easily transferred between different computers. • Job Control • In order to run the batch job the computer requires some job control which is unique to the type of machine being used. The submission package used to submit the job will generate all the job control required to run the analysis and create the appropriate files. • The Installation and Execution Guide describes how to MSC.Dytran can run on. In all cases no knowledge of the intricacies of the computer system being used is required.

  8. INPUT FILE FORMAT • Input File Structure • ... File Management Section ... • ... Executive Control ... • CEND • ... Case Control ... • BEGIN BULK • ... Bulk data entries ... • ENDDATA

  9. INPUT FILE FORMAT • File Management Section (FMS)Controls file usage and type of analysis. • Executive ControlSets resource limits. • Case Control Selects the type of output required and how often it is produced (No results output is produced by default). Makes data selections from the Bulk Data section.Controls the termination criteria for the analysis. • Bulk Data • Contains all the data necessary to define the analysis model. This typically includes: • Geometry • Element Connectivity • Element Properties • Material Properties • Constraints • Loading • Interaction • Sets the parameters used to control the analysis.

  10. ADVANTAGES OF MSC/NASTRAN STYLE INPUT • Flexible Input Format • This form of data input is very flexible: • Free or Fixed format can be used Entries can be in any order with any numbering system • Industry standard input • Since MSC.Nastran is so widely used, its form of input is virtually an industry standard for finite element analysis. Many programs can read and write this form of data file. • Compatible with most preprocessors • Virtually all major preprocessing programs can write MSC.Nastran input files. This means that they can also write MSC.Dytran input files, due to the compatibility of the programs. • One input file for all analyses • Given a certain amount of forethought, the same model and input file can be used for all types of analysis, be they performed with MSC.Nastran or MSC.Dytran. • MSC.Dytran will accept all valid MSC.Dytran data. If it is not required for an MSC.Dytran analysis, a warning message is issued and the data is ignored.

  11. ADVANTAGES OF MSC.NASTRAN STYLE INPUT (continued) • Minimize user training • Engineers and analysts already familiar with MSC.Nastran will find learning to use MSC.Dytran fairly easy, since not only are the input files essentially the same, but the documentation is very similar as well. Time spent training is therefore minimized, and engineers who normally run MSC.Nastran will be able to use MSC.Dytran on an occasional basis.

  12. FMS, EXECUTIVE CONTROL AND CASE CONTROL FORMAT • Free Format • The FMS, Executive Control and Case Control sections are in free format. That means that data items can appear anywhere on the line and are separated by commas or spaces. • ENDTIME = 1.0E-3 • SET 1 = 1, 2, 101, 102

  13. FORMAT OF DATA ITEMS • Data Types • The description of the entry in the User’s Manual gives the type of data required. It can be of three types: • • Integer • • Real • • Character • The integer and real numbers are used for numeric data; character input is used to select options on a number of entries and should consist of an alphanumeric string of characters matching one of the options available. • Variations of Real Number Input • Real numbers can be entered in a variety of ways. The following are all exactly the same as far as MSC.Dytran is concerned: • 7.0 7 0.7E1 0.7+1 • .70+1 7.+0 70.-1 70.0E-01

  14. BULK DATA FORMAT • Three Formats • There are 3 distinct styles of Bulk Data input which can be freely mixed within the input file: • Free FormatThis is the one you should use most of the time. The various fields on the entry can appear anywhere on the line, the individual items being separated by commas.GRID,10, ,7.5,8.6,9.0, ,456Free field format is denoted by the presence of a comma in the first ten columns. • Small Field Fixed Format • Each line is split into 10 fields of 8 columns each. The data for a particular field must be in the columns associated with that field, although it can appear anywhere within the field. • This type of format is identified by the absence of a comma.

  15. BULK DATA FORMAT • Large Field Fixed Format The entry occupies two lines of the input file. The first and last fields on each line consist of 8 columns each. The intermediate columns have 16 columns each.This type of format is denoted by the presence of a * after the entry mnemonic in field 1A on the first line and an * in the first column of the second line.The continuation mnemonics in fields 10A and 1B must be identical apart from the first character. It is recommended that you make them the same.If all the fields on the second line are blank, then it may be omitted.

  16. CONTINUATION LINES • Definition • An entry may take up more than one line of the data file. All lines after the first are called continuations. • Examples • Parent CHEXA,10,100,3,4,5,6,7,8,+CONT Continuation +CONT, 9, 10 • Parent CHEXA,10,100,3,4,5,6,7,8,+ Continuation +, 9, 10

  17. CONTINUATION LINES • Input Rules • Field 1 of the Continuation must be the same as Field 10 of the preceding Line • The characters in field 1 of the continuation must be the same as those in field 10 of the preceding line, except the first character. It is recommended that the two fields are identical. • The Continuation Line must start with a * for large fixed Format • Continuation Lines must follow their Parent • Each continuation line must directly follow the line which it is a continuation of. Note that this restriction does not apply in MSC.Nastran. • Formats can be mixed • There is no restriction to the format of the parent and its continuation lines. Free, small or large fixed format can be freely mixed. For example a small fixed format entry can have a free format continuation or a free format line may have a large fixed format continuation.

  18. DIFFERENCES FROM MSC.Nastran • Free format data fields can have more than 8 characters • The fields on a free format entry can be up to 16 characters as long as the whole entry fits onto one line of the input file. • Real numbers can be entered as integers • It is not necessary to have a decimal point in fields containing real numbers. • If fields 5 to 8 are blank on a large format entry, the continuation line can be omitted. • If the continuation line is omitted, fields 5 to 8 will be blank and therefore set to the default values. • Continuation mnemonics need not be unique • The same continuation mnemonic can be used many times. Indeed the mnemonic is not really necessary and it is simplest to simply leave it blank. • Continuation lines must follow their parent • Since the continuation mnemonics need not be unique, the continuation line must directly follow its parent. • If you use MSC.Nastran do not use this increased flexibility

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