PAT301, Workshop 20, October 2003 WS20-1 WORKSHOP 20 CONNECTING ROD USING 3D ELEMENTS FROM SWEEP. - презентация

1 PAT301, Workshop 20, October 2003 WS20-1 WORKSHOP 20 CONNECTING ROD USING 3D ELEMENTS FROM SWEEP

2 WS20-2 PAT301, Workshop 20, October 2003

3 WS20-3 PAT301, Workshop 20, October 2003 n Problem Description u A hex8(3D solid element) mesh model is created for the connecting rod geometry in this workshop. The tasks to be performed consist of IsoMeshing the connecting rod mid surfaces with 2D quad4 elements. These elements are then swept normal to them. The sweeping is done in three parts: one for the web, one for the flange, and one for the region at the piston and crank shaft. This is done this way because each region of the model has a different thickness, resulting in sweeping a different distance. The remaining tasks consist of creating pressure loading and constraints, creating properties, running the finite element ananlysis, and viewing the results in MSC.Patran.

4 WS20-4 PAT301, Workshop 20, October 2003 n Suggested Exercise Steps 1. Create a new database and import mid-surfaces for the connecting rod from the IGES file conrod.igs. 2. IsoMesh with quad4 elements all 30 surfaces. 3. Connect the 2D elements together by equivalencing. Then, verify that the elements have been connected. 4. Sweep the 2D quad4 elements to create 3D hex8 elements. This is done in three parts: web, flange, and connections to piston and crank shaft. The 2D elements for the web are swept first. The web is the thinnest part, with a thickness of Then, the 2D elements for the flange are swept. The thickness of the flange is Finally, the 2D elements for the remaining parts are swept. The thickness of these parts is The 3D solid elements are connected by equivalencing. A display of the element free edges before and after it is done is observed. 6. Delete the 2D quad4 elements. These are not needed for the analysis with the 3D solid elements. 7. Create a cylindrical coordinate system at the center of the hole for the connection to the piston. This is needed for creating a field, which is needed for the pressure loading.

5 WS20-5 PAT301, Workshop 20, October 2003 n Suggested Exercise Steps(Cont.) 8. Create a field using the coordinate system previously created. The field will be a scalar function of sin(theta). 9. Create the pressure loading on the inside of the top part of the connecting rod(connected to the piston). Use the field just created. The point of zero pressure loading is rotated about 20 degrees. Also, nodal displacement constraints are created at the connection to the crank shaft. Only degrees- of-freedom 1,2,3 are constrained because the elements are 3D solids. 10. Create material properties. 11. Create 3D solid element properties. 12. Check the load case Default to see that all the loads and boundary conditions are selected. 13. Submit the analysis to MSC.Nastran. 14. Look at the results. The first thing to be done is to attach the XDB results file created by MSC.Nastran. Then, look at the displacement and von Mises stress results. The displacement results are displayed with and without the undeformed shape and geometry.

6 WS20-6 PAT301, Workshop 20, October 2003 Step 1. Create New Database and Import Geometry Create a new database called connecting_rod_3D and import the IGES file. a. File : New (or click on the File New icon). b. Enter connecting_rod_3D for the File name. c. Click OK. a bc

7 WS20-7 PAT301, Workshop 20, October 2003 Step 1. Create New Database and Import Geometry (Cont.) Import the existing IGES file. a. File : Import… b. Select IGES as the Source. c. Click Apply. a b c

8 WS20-8 PAT301, Workshop 20, October 2003 Step 1. Create New Database and Import Geometry (Cont.) Select the model preferences after importing the geometry. a. Click OK when the IGES Report Summary appears. b. Select Based on Model for the Model Tolerance. c. Click OK a b c

9 WS20-9 PAT301, Workshop 20, October 2003 Step 1. Create New Database and Import Geometry (Cont.) These are surfaces that represent the mid-plane of the connecting rod.

10 WS20-10 PAT301, Workshop 20, October 2003 Step 2. Mesh the Surfaces IsoMesh the surfaces of the connecting rod. a. Elements : Create / Mesh / Surface. b. Select Quad, IsoMesh, Quad4. c. Select all the surfaces by dragging a box around them. d. Remove check under Automatic Calculation and enter for the Global Edge Length. e. Click Apply. a b c d e

11 WS20-11 PAT301, Workshop 20, October 2003 Step 3. Equivalence and Verify Free Edges Equivalence the model to connect elements. Then, display the element edges that are free to see what elements are and are not connected. a. Elements : Equivalence / All / Tolerance Cube. b. Click Apply. (the magenta circles indicate the equivalenced regions) c. Elements : Verify / Elements / Boundaries. d. Select Free Edges. e. Click Apply. (Free edges are indicated by the yellow lines.) a b c d e

12 WS20-12 PAT301, Workshop 20, October 2003 Step 4. Sweep the Elements The sweep command will be used to create 3D elements from the 2D elements. The final 3D model will not have the same thickness throughout, so 3 sets of elements will be swept. The first sweep will be done for the web of the connecting rod. a. Elements : Sweep / Element / Extrude. b. Click on Mesh Control… c. Enter 2 and click OK. d. Enter under Direction Vector. e. For Base Entity List, click on the Meshed entity Icon, then click on the Meshed Surface icon. f. Shift-select the 6 surfaces that make up the web (indicated 1-6). g. Click Apply. h. Change sign of the sweep vector, , and Apply. a b c d e f g h e

13 WS20-13 PAT301, Workshop 20, October 2003 Step 4. Sweep the Elements (Cont.) Now sweep the flange section of the connecting rod. a. Elements : Sweep / Element / Extrude. b. Click on Mesh Control… c. Enter 4 and click OK. d. Enter under Direction Vector. e. For Base Entity List, click on the Meshed entity icon, then click on the Meshed Surface icon. f. Shift-select the 6 surfaces that make up the flange (indicated 1-6). g. Click Apply. h. Change sign of the sweep vector, , and Apply f a b c d e g h e

14 WS20-14 PAT301, Workshop 20, October 2003 Step 4. Sweep the Elements (Cont.) Now sweep the piston and crank sections of the connecting rod. a. Elements : Sweep / Element / Extrude. b. Click on Mesh Control… c. Enter 5 and click OK. d. Enter under Direction Vector. e. For Base Entity List, click on the Meshed Entity icon, then click on the Meshed Surface icon. f. Shift-select the 18 surfaces, 9 that make up the piston and 9 that make up the crank(as indicated). g. Click Apply. h. Change sign of the sweep vector, , and Apply. a b c d e g h f e

15 WS20-15 PAT301, Workshop 20, October 2003 Step 4. Sweep the Elements (Cont.) Change the views and see what the 3D model looks like. a. Click on the Smooth Shaded icon. b. Click on the Fit View icon. c. Click on the Iso 1 View icon. Here are three different views of the connecting rod (From left to right, Iso 1 View, Front View, and Right Side View). It may be helpful to try other views as well. abc

16 WS20-16 PAT301, Workshop 20, October 2003 Step 5. Equivalence the Solid Check to see what elements are not connected using the Verify command. a. Elements : Verify / Element / Boundaries. b. Select Free Edges. c. Click Apply. The yellow lines indicate element free edges. Notice that these lines should not exist, i.e. the elements should be connected here. This can be resolved by using the Equivalence command. a b c

17 WS20-17 PAT301, Workshop 20, October 2003 Step 5. Equivalence the Solid (Cont.) Equivalence 3D mesh and check the free edges again. a. Elements : Equivalence / All / Tolerance Cube. b. Click Apply. c. Elements : Verify / Element / Boundaries. d. Select Free Edges and click Apply. The yellow lines indicate free edges. Notice that the lines that were here previously no longer exist. That indicates that the elements here are now connected. a b c

18 WS20-18 PAT301, Workshop 20, October 2003 Step 6. Delete Surface 2D Mesh Delete the 2D elements on the surfaces. a. Elements : Delete / Mesh / Surface. b. Select entire model by dragging a box around it. c. Click Apply. a b c

19 WS20-19 PAT301, Workshop 20, October 2003 Step 7. Create a Cylindrical Coordinate System Create a cylindrical coordinate frame that will be used as a reference frame for the field. a. Click on the wireframe icon b. Click on the Point Size icon. c. Click on the View Corners icon. Drag a box around the piston end of the rod. d. Geometry : Create / Coord / 3Point. e. Type : Cylindrical f. Click on the Point icon. g. Select Point 2 for the Origin(center of piston). Enter [x2 y2 1] for the Point on Axis 3, and select point 41 (as indicated). h. Click Apply. i. Click on Front view icon. a c d e f g h b g i

20 WS20-20 PAT301, Workshop 20, October 2003 Step 8. Create a Field Create a field that will be used as a reference for the load. a. Fields : Create / Spatial / PCL Function. b. Enter sin_load for the Field Name. c. Select Coord 1(the newly created cylindrical coord. frame) for the Coordinate System. d. Enter sinr(T) for the Scalar Function e. Click Apply. a b c d e

21 WS20-21 PAT301, Workshop 20, October 2003 Step 9. Create Loads and Boundary Conditions Create a pressure from the piston using the sin_load field. a. Loads/BCs : Create / Pressure / Element Uniform. b. Enter piston_pressure for the New Set Name. c. Click on Input Data… d. Enter 1000 for the Scale Factor, and for the Pressure click on the sin_load field. e. Click OK. f. Click Select Application Region… g. Select FEM for the Geometry Filter. h. Click on Select 3D Element Faces, then use the Polygon Pick icon for Free face of element. a b c d e f g h h

22 WS20-22 PAT301, Workshop 20, October 2003 Step 9. Create Loads and Boundary Conditions (Cont.) Select the solid element faces for the application region for the pressure. a.Set Preferences/Picking to Enclose entire entity. Close. b.Start by clicking on element just above point 41 and continue to select the element faces on the inner surface. Once all the faces have been selected to element just above point 43, (as indicated) go back to the original point (marked by a small box). c. Click Add. d. Click OK. e.Click Apply. a a b c d a

23 WS20-23 PAT301, Workshop 20, October 2003 Step 9. Create Loads and Boundary Conditions (Cont.) Zoom in on the crank section of the connecting rod in order to create the nodal constraints. a. Click on the Fit view icon. b. Click on the View corners icon and zoom in on the upper section of the crank, by dragging a box around it. Above is the illustration of the piston pressure.Above is the illustration of the crank section. ab

24 WS20-24 PAT301, Workshop 20, October 2003 Step 9. Create Loads and Boundary Conditions (Cont.) Constrain select displacements at the crank shaft. a. Loads/BCs : Create / Displacement / Nodal. b. Enter fixed_crank for the New Set Name. c. Click on Input Data… d. Enter under Translations. e. Click OK. a b c d e

25 WS20-25 PAT301, Workshop 20, October 2003 Step 9. Create Loads and Boundary Conditions (Cont.) Select the application region to finish creating the nodal constraints. a. Click on Select Application Region… b. Select FEM for the geometry filter. c. Click on Select Nodes, then use the Polygon Pick for Nodes. d. Select the nodes on the upper free faces of the crank shaft region(as indicated). e. Click OK. f. Click Apply. a b d e f c d c

26 WS20-26 PAT301, Workshop 20, October 2003 Step 9. Create Loads and Boundary Conditions (Cont.) Above is an illustration of the fixed displacements at the crank. Notice that the node at these points are also included. Above is a better illustration of the pressure and fixed displacements. Just click the Fit View, then Smooth Shaded, then Iso 1 View icons. It may be helpful to try other views as well.

27 WS20-27 PAT301, Workshop 20, October 2003 Step 10. Create Material Properties Create a material property that will be applied to the model. a. Materials: Create / Isotropic / Manual Input b. Enter Aluminum for the Material Name. c. Click on Input Properties… d. Enter 10E6 and 0.3 for the Elastic Modulus and Poisson Ratio, respectively. e. Click OK f. Click Apply. a b c d e f

28 WS20-28 PAT301, Workshop 20, October 2003 Step 11. Create Element Properties Create the element properties for the connecting rod. a. Properties : Create / 3D / Solid. b. Enter 3D_connecting_rod for the Property Set Name. c. Click on Input Properties… d. Click on the Material Prop Name icon, and select Aluminum from Select Existing Material. e. Click OK. f. Click on Select Members and FEM icon and select entire model. Then, click Add. g. Click Apply. a b c d e f g f

29 WS20-29 PAT301, Workshop 20, October 2003 Step 12. Check Load Cases Check the default load case, Default, and make sure that the correct loads and boundary conditions are being applied. a. Load Cases : Modify. b. Select the load case Default. c. Check to see that the Loads/ BCs are correct. d. Click Cancel. a b c d e

30 WS20-30 PAT301, Workshop 20, October 2003 Step 13. Run the Analysis Send the model to MSC.Nastran and run the analysis. a. Analysis : Analyze / Entire Model / Full Run. b. Click on Translation Parameters… c. Select XDB and Print. d. Click OK. e. Click on Solution Type… f. Select Linear Static. g. Click OK. h. Click Apply. a b c d e f g h

31 WS20-31 PAT301, Workshop 20, October 2003 Attach the XDB file. a. Analysis : Access Results / Attach XDB / Result Entities. b. Click on Select Results File... c. Select connecting_rod_3D.xdb and click OK. d. Click Apply. Step 14. Check the Results a b c d

32 WS20-32 PAT301, Workshop 20, October 2003 Create a deformation plot. a. Results : Create / Deformation. b. Select Displacements, Transitional. c. Click Apply. Step 14. Check the Results (Cont.) a b c

33 WS20-33 PAT301, Workshop 20, October 2003 Step 14. Check the Results (Cont.) Do not show the undeformed shape and erase the geometry to be able to see the deformed shape better. a. Click on the Display Attributes icon. b. Remove the check from the Show Undeformed box. c. Click on the Plot/Erase icon. d. Click Erase under Geometry. e. Click OK. f. Display: Coordinate Frames. g. Click on Unpost All h. Click OK. i. Click Apply i d g h a c b e f

34 WS20-34 PAT301, Workshop 20, October 2003 Step 14. Check the Results (Cont.) Plot the Von Mises stress. a. Results : Create / Fringe. b. Select Stress, Tensor. c. Click Apply. a b c

35 WS20-35 PAT301, Workshop 20, October 2003 Step 14. Check the Results (Cont.)

36 WS20-36 PAT301, Workshop 20, October 2003