NAS120%20Training

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WORKSHOP 1 LANDING GEAR STRUT ANALYSIS
NAS120, Workshop 1, November 2003
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• Problem Description
• A landing gear strut has been designed for a new
  fighter jet. Determine if the landing gear strut
  has been designed properly to withstand the
  landing load.
• E 30 x 106 psi
• n 0.3
• Landing Load 7,080 lb

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• Workshop Objectives
• Learn the typical workflow of a finite element
  analysis using MSC.Patran and MSC.Nastran.

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• Suggested Exercise Steps
• Create a new database and name it strut.db.
• Import the strut geometry.
• Mesh the strut to create solid elements.
• Apply Loads and Boundary Conditions.
• Create material properties.
• Create physical properties.
• Run analysis with MSC.Nastran.
• Read the results into MSC.Patran.
• Plot the Von Mises stress and displacement.

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Step 1. Create New Database
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• Create a new database called strut.db
• File / New.
• Enter strut as the file name.
• Click OK.
• Choose Tolerance Based on Model.
• Select MSC.Nastran as the Analysis Code.
• Select Structural as the Analysis Type.
• Click OK.

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Step 2. Import Geometry
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• Import the parasolid file
• File Import.
• Select the file strut.xmt.
• Click Apply.

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Step 3. Mesh the Object
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• Create a solid mesh
• Elements Create / Mesh / Solid.
• Select the entire solid.
• Deselect Automatic Calculation under Global Edge
  Length.
• Enter 0.5 for the Global Edge Length.
• Click Apply.
• Click on the Iso2 View Icon.

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Step 4. Apply Loads and Boundary Conditions

• Create a boundary condition
• Loads/BCs Create / Displacement / Nodal.
• Enter hub cylinder as the New Set Name.
• Click Input Data.
• Enter lt0 0 0gt for Translations.
• Click OK.

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Step 4. Apply Loads and Boundary Conditions

• Apply the boundary condition
• Click Select Application Region.
• For the Geometry Filter select Geometry.
• Set the Selection Filter to Surface or Face and
  select the cylinder at the bottom of the strut,
  as shown.
• Click Add.
• Click OK.
• Click Apply.

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Step 4. Apply Loads and Boundary Conditions

• Create a load
• Loads/BCs Create / Total Load / Element Uniform.
• Enter landing load as the New Set Name.
• Click Input Data.
• Enter lt0 7080 0gt for Load.
• Click OK.

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Step 4. Apply Loads and Boundary Conditions

• Apply the load
• Click Select Application Region.
• For the Geometry Filter select Geometry.
• Select the upper circular surface at the top of
  the strut, as shown.
• Click Add.
• Click OK.
• Click Apply.

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Step 5. Create Material Properties

• Create an isotropic material
• Materials Create / Isotropic / Manual Input.
• Enter steel for the Material Name.
• Click Input Properties.
• Enter 30e6 for the Elastic Modulus.
• Enter 0.3 for the Poisson Ratio.
• Click OK.
• Click Apply.

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Step 6. Create Physical Properties

• Create physical properties
• Properties Create / 3D / Solid.
• Enter strut as the Property Set Name.
• Click Input Properties.
• Select steel as the material.
• Click OK.

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Step 6. Create Physical Properties

• Apply the physical properties
• Click in the Select Members box.
• Screen pick the entire solid as shown.
• Click Add.
• Click Apply.

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Step 7. Run Linear Static Analysis

• Analyze the model
• Analysis Analyze / Entire Model / Full Run.
• Click Solution Type.
• Choose Linear Static as the Solution Type.
• Click OK.
• Click Apply.

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Step 8. Read Results into MSC.Patran

• Attach the results file
• Analysis Access Results / Attach XDB / Result
  Entities.
• Click Select Results File.
• Choose the results file strut.xdb.
• Click OK.
• Click Apply.

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Step 9. Plot Stress and Displacement
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• Create a quick plot
• Results Create / Quick Plot.
• Select Stress Tensor as the Fringe Result.
• Select Displacements, Translational as the
  Deformation Result.
• Click Apply.
• Click on the Iso1 View Icon.

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