WS15e-1 WORKSHOP 15E MODAL ANALYSIS OF TUNING FORK USING 1D ELEMENTS NAS122, Workshop 15e, August 2005 Copyright 2005 MSC.Software Corporation

WS15e-2 NAS122, Workshop 15e, August 2005 Copyright 2005 MSC.Software Corporation

WS15e-3 NAS122, Workshop 15e, August 2005 Copyright 2005 MSC.Software Corporation MODAL ANALYSIS OF A TUNING FORK n Problem Description u In this workshop the user is going to create a geometric representation of the tuning fork using geometric curves. The model will be meshed with bar elements to create a 1D Finite Element representation of the tuning fork. The model is then submitted to MSC.Nastran for Normal Modes analysis and the results are compared to those obtained in the workshop where the tuning fork is represented by solid elements.

WS15e-4 NAS122, Workshop 15e, August 2005 Copyright 2005 MSC.Software Corporation MODAL ANALYSIS OF A TUNING FORK n Suggested Exercise Steps 1. Using the Create / Curve / XYZ tool, create the stem of the tuning fork. 2. Create the neck of the tuning fork using the 2D ArcAngles tool. 3. Finish modeling the rest of the tuning fork using the Curve / XYZ tool. 4. Mesh the geometry with Bar2 elements. 5. Equivalence the finite element model to eliminate all the coincidental nodes. 6. Create a material properties set to represent steel. 7. Assign physical properties to the finite element model. 8. Submit the model to Nastran for a Normal Modes analysis. 9. Attach the XDB result file after the analysis is completed. 10. Use the Deformation Plot feature in the Result Menu to visualize the Eigenvector of the model.

WS15e-5 NAS122, Workshop 15e, August 2005 Copyright 2005 MSC.Software Corporation CREATE NEW DATABASE Create a new database called tuning fork stick.db. a.File / New. b.Enter tuning fork stick as the file name. c.Click OK. d.Choose Default Tolerance. e.Select MSC.Nastran as the Analysis Code. f.Select Structural as the Analysis Type. g.Click OK. a b c d e f g

WS15e-6 NAS122, Workshop 15e, August 2005 Copyright 2005 MSC.Software Corporation Step 1. Geometry: Create / Curve / XYZ Create the stem of the tuning fork. a.Geometry: Create / Curve / XYZ. b.Enter for the Vector Coordinate List. c.Uncheck Auto Execute. d.Click Apply. a b c d

WS15e-7 NAS122, Workshop 15e, August 2005 Copyright 2005 MSC.Software Corporation Step 2. Geometry: Create / Curve / 2D ArcAngles Create the joint of the tuning fork. a.Geometry: Create / Curve / 2D ArcAngles. b.Enter 0.25 for the Radius. c.Enter 180 for the Star Angle and 360 for the End Angle. d.Enter [ ] for the Center Point List. e.Click Apply. a b c d e

WS15e-8 NAS122, Workshop 15e, August 2005 Copyright 2005 MSC.Software Corporation Step 3. Geometry: Create / Curve / XYZ Create the Node of the tuning fork. a.Geometry: Create / Curve / XYZ. b.Enter for the Vector Coordinate List. c.Pick the two end point of the joint for the Origin Coordinates List. d.Click Apply. a b c d

WS15e-9 NAS122, Workshop 15e, August 2005 Copyright 2005 MSC.Software Corporation Step 4. Elements: Create / Mesh / Curve Create the finite elements for the tuning fork. a.Elements: Create / Mesh / Curve. b.Select all the curves from the screen. c.Uncheck the Automatic Calculation and enter 0.1 Value. d.Click Apply. a b c d

WS15e-10 NAS122, Workshop 15e, August 2005 Copyright 2005 MSC.Software Corporation Step 5. Elements: Equivalence / All / Tolerance Cube Merge all the coincidental nodes. a.Elements: Equipvalence / All / Tolerance Cube. b.Click Apply. a b

WS15e-11 NAS122, Workshop 15e, August 2005 Copyright 2005 MSC.Software Corporation Step 6. Material: Create / Isotropic / Manual Input Create the material properties. a.Materials: Create / Isotropic / Manual Input. b.Enter steel for the Material Name. c.Click on Input Properties. d.Enter 26.77E6 for Elastic Modulus and 0.3 for Poisson Ratio. e.Enter for the Density. f.Click OK. g.Click Apply. a b c d e f g

WS15e-12 NAS122, Workshop 15e, August 2005 Copyright 2005 MSC.Software Corporation Step 7. Properties: Create / 1D / Beam Assign the Element Properties to the tuning fork model. a.Properties: Create / 1D / Beam. b.Enter tuning_fork for the Property Set Name. c.Click on Input Properties button. d.Click in the Material Prop Name icon, and select steel from the Material Property Sets. e.Enter for the Bar Orientation. f.Click on Beam Library Icon. g.Enter rod for the New Section Name. h.Select the solid circular cross section. i.Enter for the Radius. j.Click OK. k.Click OK. l.Select all the curves from the screen for the Application Region. m.Click Add. n.Click Apply. a b c k e l d m n f g h i j

WS15e-13 NAS122, Workshop 15e, August 2005 Copyright 2005 MSC.Software Corporation Step 8. Analysis: Analyze / Entire Model / Full Run Submit the tuning fork for normal modes analysis. a.Analysis: Analyze / Entire Model / Full Run. b.Click on Solution Type. c.Select NORMAL MODES. d.Click on Solution Parameters. e.Change the Wt-Mass Conversion to f.Click OK on both sub-forms. g.Click Apply to submit the model for analysis. a c d e f f g b

WS15e-14 NAS122, Workshop 15e, August 2005 Copyright 2005 MSC.Software Corporation Step 9. Analysis: Access Results / Attach XDB / Result Entities Attach the XDB result file. a.Analysis: Access Results / Attach XDB / Result Entities. b.Click on Select Results File… c.Select tuning_fork_stick.xdb. d.Click OK. e.Click Apply. a b c d e

WS15e-15 NAS122, Workshop 15e, August 2005 Copyright 2005 MSC.Software Corporation Step 10. Results: Create / Deformation Create a Deformation Plot of the models Mode Shape. a.Results: Create / Deformation b.Select the A1: Mode 7. c.Select Eigenvector, Translational in the Select Deformation Result box. d.Click Apply. b a c d

WS15e-16 NAS122, Workshop 15e, August 2005 Copyright 2005 MSC.Software Corporation Summary Summary of Frequencies and Modes for project _______________ ModeFreq (Hz) Description