Aprendiendo abaqus

10/27/2006

ES 240

Nanshu Lu

Learning ABAQUS: 3-Bar Truss Example Problem

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The file truss-3br.inp (or 1.3_truss-3br.inp in this folder) is an ABAQUS input file for finite-element static analysis of the 3-bar truss structure shown above. Input files should be named in the form input-filename.inp, where input-filename is anything of your choosing, so that your .inp file is, e.g.,mytruss.inp, Elizabeth-truss.inp, etc. It is usually convenient to keep the jobname close, but not identical to input-filename (to avoid confusion if you later want to delete unsuitable results), e.g., jobname as mytruss1 or Elizabeth-truss-a.inp. Read through the input file to get a feel for the structure of an ABAQUS input file. Next, run the job using the command: abaqus j=jobname and then followthe dialog and give the name of the .inp without the .inp extension (i.e., give it as input-filename, not input-filename.inp) Files Created. You should see files with the following extensions (for jobname = Truss-test) created in the directory after your analysis is complete.
Truss-test.com: Command file, created by the ABAQUS execution procedure Truss-test.dat: Printed output file. It is writtenby the analysis, datacheck, parametercheck, and continue options. It contains tabulated information of requested variable outputs. Truss-test.log: Log file, which contains start and end times for modules run by the current ABAQUS execution procedure, and will display error messages if the procedure did not run successfully.

Truss-test.msg: Message file; may contain error messagesTruss-test.odb: Output database. It is written by the analysis and continue options. It is read by the Visualization module in ABAQUS/CAE (ABAQUS/Viewer). Truss-test.par: Modified version of original parametrized input file showing input parameters and their values. Truss-test.pes: Modified version of original parametrized input file showing input free of parameter information (after input parameterevaluation and substitution has been performed Truss-test.pmg: Parameter evaluation and substitution message file. It is written when the input file is parametrized Truss-test.prt: Part file. This file is used to store part and assembly information and is created even if the input file does not contain an assembly definition. Truss-test.sta: Status file. ABAQUS writes increment summaries to this file inthe analysis, continue, and recover options

Files You Need to Keep. Only the .odb file is necessary for viewing results, and this is the only file you absolutely must keep after running an analysis. The .dat file is useful to keep because it can contain requested variable outputs. The .par file is useful to keep because it will tell you the values of parameters used in the analysis. All otherfiles can be deleted. While the analysis is running, there is a file input-filename.lck present. When this file disappears, the analysis has ended. After the analysis is complete, first open the .log and look for the line “ABAQUS JOB jobname COMPLETED” at the bottom of the file. If an analysis ends with errors, you need to check the .sta, .dat, and .msg files for error messages. Next, open the .datfile. Towards the end of the file you will see the tables containing the requested variable outputs. Viewing Results. To view results, you will need to open ABAQUS/Viewer. Once you have started Viewer, click on Open Database (see figure on next page)

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and open the output database file for the truss problem. To plot the deformed shape, select the menu “Plot” then select “Deformed Shape.” Ifyou would like to superimpose the undeformed shape on the deformed shape, select the “Options” menu, and select Deformed Shape. In the Deformed Shape Options Dialog box, check the box marked “Superimpose undeformed plot.” (see figure on next page for plot of deformed shape)

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You can plot contours of various variables, such as stress and strain. Explore the options available in Viewer,...