SOF111, Tutorial 1, January 2005 Copyright  2005 MSC.Software Corporation T1-1 TUTORIAL 1 LS-DYNA MODEL PREPARATION

SOF111, Tutorial 1, January 2005 Copyright  2005 MSC.Software Corporation T1-2

SOF111, Tutorial 1, January 2005 Copyright  2005 MSC.Software Corporation T1-3 Table Of Contents SectionPage Step1. Import Nastran Deck. 3 Step2. Check Model Statistics. 4 Step3. Modify Part.. 5 Step4. Modify Material Properties. 6 Step5. Create X-Y Plots. 7 Step6. Import X-Y Plots. 8 Step7. Penetration checking. 9 Step8. Penetration Fixing. 10 Step9. Quality Check On Element Length Criteria. 11 Step10. Fix the element lengths. 12 Step11. Delete un-needed entities from Nastran model. 13 Step12. Change Units. 14 Note: As in the other tutorials, all menu items that need to be selected will be preceded by a maroon right arrow: >User action. Mouse buttons are indicated as follows: -- 1B = First (left) button -- used for selecting items -- 2B = Second (middle) button -- used for "OK" -- 3B = Third (right) button -- used for View Manipulation & pop-up menus Normally 1B is used, unless otherwise.

SOF111, Tutorial 1, January 2005 Copyright  2005 MSC.Software Corporation T1-4 Step1. Import Nastran Deck. a.Launch MSC.SOFY according to your local configuration. b.Select >LS-DYNA mode from entry screen. c.You'll be importing and converting a Nastran deck. d.First, set the units to match the file being imported: - Select >Options menu >Units Mgr. e.In the Units Manager dialog box :- Select >Standard Units button >which brings up another pop-up with several choices of units. f.Choose >NASTRAN (without WTMASS card) >OK. g.Check that the derived units are appropriate, as well. h.For example, you should choose >N-mm for torque to maintain a consistent set of units. i. When finished, >Exit the dialog box. j.Now to import the NASTRAN deck,:- Select >File menu >Import >NASTRAN. k.In the dialog box "Select Nastran file to merge" navigate to the file.../DEMOS/Tutorials_NASTRAN/Tut_N-1_floor.nas and then >Open. l.Watch the message area at the bottom for any error messages. m. When complete, a text editor window should pop up with a file "MSC.SOFY.err" showing any Nastran cards which failed to convert to LS-Dyna. n.You should have the following model on the canvas. n f

SOF111, Tutorial 1, January 2005 Copyright  2005 MSC.Software Corporation T1-5 Step2. Check Model Statistics. Find out some statistics about the model a.Select >Statistics icon from tool bar. b.An information panel comes up with the statistics about the current scene, such as number of parts, number of elements, and so on. c.The Nastran material cards were all converted to type 024 Piecewise Linear Plasticity and all RBE2 rigids were converted to Nodal Rigid Body elements. Only entities currently displayed are included in the Statistics b a

SOF111, Tutorial 1, January 2005 Copyright  2005 MSC.Software Corporation T1-6 Step3. Modify Part. Let's examine and modify some of the parts in the model. a.From Collection block> Type> Part should already be displayed. b.Click with >3B over the part name: >PNL_RR_FLR c.Then from the pop-up> select >Modify. d.In the Modify Part dialog, if you hover your mouse over each field, its description appears at the bottom. e.In some cases you can double-click on the field to Select / Modify/Create. c d

SOF111, Tutorial 1, January 2005 Copyright  2005 MSC.Software Corporation T1-7 Step4. Modify Material Properties. a.Double click in >MID (Material ID) > select >Modify. b.Another dialog opens with the card image of the 024 MAT card. c.You can type in any field to replace the values shown, or again, in some fields you can double-click to Select / Modify / Create. d.Double-click in >LCSS field (Load Curve, Stress- Strain) e.Select >Create. f.Choose >DEFINE_CURVE from the next pop-up and >OK. b f

SOF111, Tutorial 1, January 2005 Copyright  2005 MSC.Software Corporation T1-8 Step5. Create X-Y Plots. a.The MSC.SOFY Grapher is now launched. b.You can enter in X-Y pairs of data on the right side, or select points graphically, as follows: From >View >Set Range. c.Enter in an appropriate min/ max range of Stress & strain values. d.Then to define the curve Edit >Current Curve >Add Point. e.Define graph points with the mouse on the graph. f.Click> Modify then >Exit the panel. b f

SOF111, Tutorial 1, January 2005 Copyright  2005 MSC.Software Corporation T1-9 Step6. Import X-Y Plots. a.If you have existing Load Curves, you can import them by Click >File Open icon in the MSC.SOFY Grapher window. b.Browse to the location of your x-y plot file (*.plt) c.Click >Open. d.In this fashion, you can do multi-level traversing through card images. e.Alternatively, you can access Materials, Load curves, etc. from the Collection block. f.Click >Type >Material. g.For example. Right-click (>3B) over any material on the list to access the Modify panel, as above. h.Click >3B over the list area also gives you the opportunity to >Create new materials. i.Change >Type to >Load Curves to access and Modify the Load curve you created in above. b

SOF111, Tutorial 1, January 2005 Copyright  2005 MSC.Software Corporation T1-10 Step7. Penetration Checking. Let's check and fix penetration between parts. a.From top menu bar >Modules> select >Penet.>Check. b.In Pick block> click drop-arrow> pick >Among Picked Parts. c.Now from the canvas, select the floor panel, >PNL_RR_FLR and the >xsill_rr. d.Confirm with >2B. e.The elements which have penetration are saved in a Set, and a Collection block clone pops up. f.Click >3B over one of the Sets gives you a choice to Highlight the elements. or g.Select >Equal to keep only those elements in the display. b e f

SOF111, Tutorial 1, January 2005 Copyright  2005 MSC.Software Corporation T1-11 Step8. Penetration Fixing. To view and change options for penetration fixing a.Select >Modules >Penet >Set Options. (Also available from >Param button in Pick block.) b.These options set maximum movement allowed (% of part thickness) at the part, surface, and local levels. c.Accept the default values >click >OK. d.Now to fix the penetration, Select >Modules >Penet >Fix e.Pick the same two parts as before.(>PNL_RR_FLR and >xsill_rr.) f.Click >Done. g. The message are will indicate if the penetration is fixed. d g

SOF111, Tutorial 1, January 2005 Copyright  2005 MSC.Software Corporation T1-12 Step9. Quality Check On Element Length Criteria. In LS-Dyna analysis you may want to control the minimum length of shell elements. Let's perform a quality check, focusing on the element length criterion. a.From >Element menu>select >Quality >Check Quality. b.This opens up a Quality check form. c.Disable (un-check) all element and model checks, except for >Length Degeneracy (collapsed elements), and >Element Length. d.Set Minimum Length Dengeracy at >1.0. e.For Element Length set Min at >3.0, Max at >35, and Ideal at >10. f.At bottom of form click >More Options. g.On right side, set Minimum Good at >4 and Maximum Good at >25. h.At bottom, check the box >Output File? i.Click >Apply >OK. j.A text editor window pops up with the file quality.out, showing all elements which failed the quality check. k.Close the window, and note that the elements are also highlighted on the canvas. d e g j

SOF111, Tutorial 1, January 2005 Copyright  2005 MSC.Software Corporation T1-13 Step10. Fix The Element Lengths. Now to fix the element lengths: a. In Collection block >Select>Type >Set. b.Click with >3B over the set >Elem. Length c.Click >Equal. d.This leaves only the failed elements on the canvas. e.Click the >Grow Mesh icon a few times to bring up the surrounding elements. f.Now go to >Element >Quality >Enhance Quality. g.In Pick block> click >Disp to select the displayed elements, h.Click >Done. i.In the Quality Enhancer Dialog, accept the default values >click >Enhance. j.After the quality enhancement is complete another pop-up summarizes the results. k.Most likely all elements are not fixed on the first pass, although in this case over 90% were fixed. l.It may be useful to add more element checks to the Quality Check form and re-execute the Quality Check and Enhance steps.

SOF111, Tutorial 1, January 2005 Copyright  2005 MSC.Software Corporation T1-14 Step11. Delete Un-Needed Entities From Nastran Model. Delete some un-needed entities that were imported with the Nastran deck. a.In Collection Block>Select>Type to >BC Sets. (Boundary Condition sets). b.Click >All On button. c.Now go to >Edit menu >Delete FEM. d.In Pick block there are several entity types to select from. e. To delete all the Loads and Constraints from NASTRAN, Select >BC Sets. f.Click >All and >Done. b

SOF111, Tutorial 1, January 2005 Copyright  2005 MSC.Software Corporation T1-15 Step12.Change Units. You can change the units to your own preference. a.From >File menu> select >Units Mgr. b.Click on the >Standard Units button. c.From the pop-up> select >Crash units d.Click >OK. e.Now >Exit the Units Manager. f.Save the file as a SOFY database: File >Save As and enter in a file name: >floor_dyna.sof into the appropriate directory. g.Click >Save. Exit MSC.SOFY: >File >Quit. Congratulations!!! You have just completed LS-Dyna Tutorial 1. c

SOF111, Tutorial 1, January 2005 Copyright  2005 MSC.Software Corporation T1-16