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NX Análisis de Piezas en Contacto
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You will learn how to:
Define contact between surfaces.
Set up and solve two different solution subcases
Simulation
This activity analyzes a pulley assembly. There is a steel shaft and nylon pulley that is press-fitted onto the shaft. Open Look in:wheel_shaft_assy
Files of type Part Files (*.prt)
File namewheel_shaft_assy.prt
OK
Start Advanced Simulation
Reset the dialog box settings
The options you select in NX dialog boxes are preserved for the next time you open the same dialog box within an NX session. To ensure that the dialog boxes are in the expected initial state for each step-by-step activity, you should restore the default settings. Preferences User Interface Reset Dialog Box Settings
OK
Create a FEM file
Simulation Navigator Simulation File View
wheel_shaft_assy New FEM Simulation
NX Nastran Fem Millimeters
Namewheel_fem1.fem
Folderyour part file folder name
OKNew Part File dialog box
SolverNX NASTRAN
Analysis TypeStructural
OK New FEM dialog box
Note:In the Simulation Navigator, notice that there are two polygon bodies. Save (Standard toolbar)
Mesh the part
Simulation Navigator wheel_fem1 New Mesh3DTetrahedral TypeCTETRA(10)
Automatic Element Size Apply
TypeCTETRA(10)
Automatic Element Size OK
Change pulley mesh display color
Simulation Navigator 3D Collectors (expand) Solid(2) Mesh Collector Display Properties Color swatch Light Hard Green Note:Or select a similar color. OK
Assign material properties
Retrieve Nylon and Steel from the materials database and assign them to the shaft and pulley.Assign Steel to the shaft.Simulation Navigator 3D Collectors (expand) Solid(1)Edit Modify Selected (Name) Choose material (Material) Materials
Steel
OKall dialog boxes
Assign Nylon to the pulley.Simulation Navigator 3D Collectors (expand) Solid(2) Edit Modify Selected (Name) Choose material (Material) Materials
Nylon
OKall dialog boxes
Create the Simulation file
Up to this point, you have been working in the FEM file. You need to create the Simulation file to define contact, constraints, and the solution. When you define the solution, you will also set some parameters required for contact.Simulation Navigator Simulation File View
wheel_fem1 New Simulation Simulation
NX Nastran Sim Millimeters
Namewheel_sim1.sim
Folderyour part file folder name
OK New Part File dialog box
OK New Simulation dialog box
SESTATIC 101 Single Constraint
Case Control
Create Modeling Object (Contact Parameters) Contact Changes for ConvergenceNumber of Contact Changes
Allowable Number of Contact Changes20
Contact StatusStart from Previous
Initial Penetration / gapSet to Zero
OKall dialog boxes
Simulation Navigator Subcase - Static Loads 1 Rename Preload Only
Define contact
Define contact between the red face of the shaft and the yellow face of the pulley. You need to turn on and off the visibility of the polygon bodies so that you can easily select the correct faces.Simulation Navigator wheel_fem1.fem (expand) 3D Collectors (deselect to turn off the display of both meshes) Polygon Geometry (expand) Polygon Body_1 (deselect to turn off the display of the pulley body) Surface-to-Surface Contact (Advanced Simulation toolbar, Simulation Object Type list) TypeManual
Source Region Target Region the Surface-to-Surface Contact dialog box title bar, to hide it Simulation Navigator Polygon Body_1 (select) Polygon Body_2 (deselect to turn off the display of the shaft body) the Surface-to-Surface Contact dialog box title bar, to restore it Properties
Source Offset0.05
Note:This simulates a 0.1 mm press fit on the diameter. OK
Polygon Body_2 (select)
Define constraints
Define a fixed constraint and a user-defined constraint that fixes the Tt (theta) and Tz (axial) displacement of the outer polygon edge on the X face of the pulley hub. Fixed Constraint (Advanced Simulation toolbar, Constraint Type list) Type FilterPolygon Face
Tip: The Type Filter is located on the Selection bar in the toolbar area.
OK
Simulation Navigator Polygon Body_2 (deselect to turn off the display of the shaft body) User Defined Constraint (Advanced Simulation toolbar, Constraint Type list) Type Filter (Selection bar) Polygon Edge
(edge of X face of the pulley hub)
Displacement CSYSCylindrical
Inferred (Local list) (edge of X face of the pulley hub)
The cylindrical coordinate system is inferring its location from this edge. DOF2Fixed
DOF3Fixed
OK
Display the pulley
Simulation Navigator Polygon Body_2 (select) Save (Standard toolbar)
Solve the model
Simulation NavigatorNote:This solution will take a few minutes on a desktop PC. Solution 1 Solve OK
Wait for the job to finish and for the command window to close.the Information window Cancel Analysis Job Monitor dialog box
Close Solution Monitor dialog box
View the analysis results
Simulation Navigator Results (under Solution 1) Post-Processing Navigator Solution_1 (expand) Displacement - Nodal (expand) Magnitude
When you finish looking at the results, return to the model.Return to Model (Layout Manager toolbar)
Define a new solution subcase
Define a new subcase to explore how a different load affects the part.Simulation Navigator Solution 1 Create Subcase NamePreload and Operating
OK
Define an operating load
Force (Advanced Simulation toolbar, Load Type list) Type Filter (Selection bar) Polygon Face
TypeNormal
Force5000
Distribution
MethodTotal per object
OK
Solve the model again
Simulation NavigatorNote:This solution will take a few minutes on a desktop PC. Solution 1 Solve OK
Wait for the job to finish and for the command window to close.the Information window Cancel Analysis Job Monitor dialog box
Close Solution Monitor dialog box
View the analysis results
Simulation Navigator ResultsPost-Processing Navigator Solution_1 (expand) Load Case 2 (expand) Displacement - Nodal (expand) Magnitude
Stress - Element Nodal (expand) Von-Mises
When you finish looking at the results, return to the model.Return to Model (Layout Manager toolbar) File Close All Parts