WORKSHOP 3 FRAME MODEL CREATION USING CURVES, AND ANALYSIS

1、WS3-1 WORKSHOP 3 FRAME MODEL CREATION USING CURVES, AND ANALYSIS WS3-2 lWorkshop Objectives lModel a simple frame structure using geometric curves and 1D Bar elements. The frame model is to be constrained using pin restraints, and the loading is to be comprised of concentrated forces and inertial lo

2、ading (load due to gravity). An analysis is to be done, and the results displayed. lProblem Description lDisplay structural model deformation and axial Bar stress lFrame material: Aluminum with E = 10 x 106 psi, n = 0.3, and density = 2.61 x 10-4 lbf sec2/in4 lLoad on frame l Dead loads, operating s

3、tatic load, and gravity load lSoftware Version lPatran 2008r2 lMD Nastran R3 WS3-3 Suggested Exercise Steps Suggested Exercise Steps Create a new database and name it frame. Create a geometric surface (Shown in Figure 1) composed of 18 curves with each curve being 24” in length. Create a mesh on the

4、 curve with global edge length = 12. Equivalence the model nodes to connect elements along surface edges. Create dead Load from the Engine with nodal forces being 150 and 960 shown in figure 1. Create operating engine static load with nodal forces on the same two nodes as the dead load of 960. Creat

5、e gravity load = on the geometry. Create constraints on four points at the corner of the frame support. Create an isotropic material for Aluminum with elastic modulus of 10E6, poisson ratio of 0.3 and density of 2.61e-4. Define the properties of the frame structure with Bar Orientation: , Area: 10,

6、Inertia1,1: 40, intertia2,2: 8, and Torsional Constant: 80. WS3-4 Suggested Exercise Steps (cont.) Check the load cases and verify that the load and boundary condition are included. Set up and perform an analysis: Solution Type = Linear Static, Solution Sequence = 101. Save the database under the na

7、me frame.xdb and attach the results. Plot bar stresses and deformation with scale factor of 0.01. WS3-5 Figure 1 WS3-6 lKey Concepts and Steps: Database: create a new database with Analysis Code = MD Nastran and Analysis Type = Structural Geometry: create curves to represent the frame structure Elem

8、ents: mesh the curves with Bar2 elements Loads/BCs: constrain the four corners of the frame, and apply the dead loads, operating static load, and gravity load Materials: specify an isotropic material for Aluminum Properties: create a 1D Beam property Analysis: Solution Type = Nastran Linear Static,

9、Solution Sequence = 101, Method = Full Run Analysis: access analysis results by attaching the XDB file to database Results: plot displaced structural shape and Bar Stress, Axial X- Component results WS3-7 Step 1. Create a Database Create a new database: File / New Enter frame as the file name. Click

10、 OK. Choose Default Tolerance. Select MD Nastran as the Analysis Code. Select Structural as the Analysis Type. Click OK. a. b e f d c g a WS3-8 Step 2. Create Geometry of the Frame Geometry: Create / Curve / XYZ Enter in the Vector Coordinates List text box. Click Apply. a b c WS3-9 Step 2. Create G

11、eometry of the Frame (Cont.) Geometry: Transform / Curve / Translate Enter in the Direction Vector text box. Repeat Count: 4 Curve List: select Curve 1. Click on Label control. A Labels toolbar will appear. From the Labels toolbar select the Curve icon. You should see 5 curves as shown in the figure

12、. Note: We will leave the Auto Execute option checked. This allows the step to be executed automatically without clicking on Apply. a b c d e f WS3-10 Step 2. Create Geometry of the Frame (Cont.) Geometry: Transform / Curve / Translate Enter in the Direction Vector List text box. Repeat Count: 1 Cur

13、ve List: Select all the curves displayed on the screen (Curves 1:5). a b c d WS3-11 Step 2. Create Geometry of the Frame (Cont.) Geometry: Transform / Curve / Rotate Rotate Angle: 90 Repeat Count: 1 Curve List: select Curve 1 and 2. a b c d d WS3-12 Step 2. Create Geometry of the Frame (Cont.) Geome

14、try: Transform / Curve / Translate Enter in the Direction Vector List text box. Repeat Count: 1 Curve List: select Curve 11 and 12. Enter in the Direction Vector List text box. Click Apply. Enter in the Direction Vector List text box. Click Apply. a b c d f d e h g WS3-13 Step 2. Create Geometry of

15、the Frame (Cont.) Your model should look like the given figure. The model is made of congruent curves. a WS3-14 Step 3. Meshing the Curves Change view to Iso3view. Elements: Create / Mesh / Curve Uncheck the Automatic Calculation option. Enter 12.0 for Global Edge Length Value. Select on Curve List

16、and include all curves. Click and drag as shown in the figure to select all curves. Click Apply. Turn off the Curve label icon and click on the Node label icon. Turn off the Label Control icon to make the Labels toolbar disappear. b c d e f a g e h WS3-15 Step 4. Equivalence “All” Nodes Elements: Eq

17、uivalence / All / Tolerance Cube. a. Click Apply. a b The magenta colored circle indicates that a node was deleted. WS3-16 Step 5. Create Dead Load from Engine Create the first of three sets of loads: Loads / BCs: Create / Force / Nodal Enter dead_load as the New Set Name. Click Input Data. Enter fo

18、r Force . Click OK. Click Select Application Region. a. Geometry Filter: FEM. a b c d f e g WS3-17 Step 5. Create Dead Load from Engine (Cont.) Click in the Select Nodes text box, and select the nodes as shown in the figure. Click Add. Click OK. Click Apply. h k h j i WS3-18 Step 5. Create Dead Load

19、 from Engine (Cont.) Create the second of three sets of loads: Now, enter dead_load_2 as the New Set Name. Click on Input Data. Enter for Force . Click OK. Click on Select Application Region. a. Geometry Filter: FEM a b c d e f WS3-19 Step 5. Create Dead Load from Engine (Cont.) Click in the Select

20、Nodes text box, and select the nodes as shown in the figure. Click Add. Click OK. g.Click Apply. h g g i j WS3-20 Step 6. Create Operating Engine Static Load Create the third of three sets of loads: Enter op_static_load as the New Set Name. Click Input Data. Enter for Force . Click OK. Click on Sele

21、ct Application Region. Geometry Filter: FEM. a b c d e f WS3-21 Click in the Select Nodes text box, and select the nodes as shown in the figure. Click Add. Click OK. g.Click Apply. Step 6. Create Operating Engine Static Load (Cont.) j g g i h WS3-22 Step 7. Create Gravity Load on Frame Loads / BCs:

22、Create / Inertial Load / Element Uniform Enter gravity as the New Set Name. Click on Input Data. Enter for Trans Accel . Click OK. Click Apply. a b c d e The application region is not specified explicitly by the user. The application region is created by all elements for which density is specified.

23、f WS3-23 Step 8. Create Constraints for the Frame Support Constrain the corner of the frame, fixing three translational degrees of freedom: Loads / BCs: Create / Displacement / Nodal Enter fix_base as the New Set Name. Click Input Data. Enter for Translations . Click OK. Click on Select Application

24、Region. a. Select Geometry for Geometry Filter. a b c d ef g WS3-24 Pick the Point or Vertex icon. Click in the Select Geometry Entities text box, and select the four points at the corners of the frame support, as shown in the figure. Click Add. Click OK. h.Click Apply. Step 8. Create Constraints fo

25、r the Frame Support (Cont.) i k l h j i WS3-25 Step 8. Create Constraints for the Frame Support (Cont.) Although the force directions may appear vertical, they are, in fact, at an angle. You can switch to different views to observe this. Use the Model Orientation toolbar to switch to different views

26、. a. When finished observing different views, hide the Loads/BCs vectors by clicking on the Reset graphics icon. ab WS3-26 Step 9. Defining Material We will set aluminum as the material of the frame: Materials: Create / Isotropic / Manual Input Enter aluminum as the Material Name. Select Input Prope

27、rties. Enter: Elastic Modulus: 10e6 Poisson Ratio: 0.3 Density: 2.61e-4 Click OK. a. Click Apply. a b c d e f WS3-27 Step 10. Defining Properties for Frame Structure Properties: Create / 1D/ Beam Enter al-plate as the Property Set Name. Click on Input Properties. a. Click on the Mat Prop Name icon a

28、nd select aluminum from the Select Material list. a b c d d WS3-28 Step 10. Defining Properties for Frame Structure (Cont.) Bar Orientation: Area: 10 Inertia 1,1: 40 Inertia 2,2: 8 Torsional Constant: 80 e.Click OK. e f h i g j WS3-29 Step 10. Defining Properties for Frame Structure (Cont.) Use Labe

29、l Control icon to display curve labels, and remove node labels. Click on Select Application Region. Select all curves. (Curves 1:18) Click Add. Click OK. Click Apply. l n o m p k m k WS3-30 Step 11. Check Assignment of Loads and BCs to Load Case Load Cases: Modify Select Default in Existing Load Cases. Check that all Loads and BCs are selected. Click Cancel. a b c d WS3-31 Step 12. Analysis Run the analysis of the entire model: Analysis: Analyze / Entire Model / Full Run Click on Solution Type. Choose LINEAR STATIC for Solution Type. Click OK.