GEOMETRY MODEL OF A 3-D CLEVIS

Workshop 1 – Introduction to MSC.Patran Objectives Create a new database for the model. Create the geometry of the clevis. Alter the graphics display of the model.

Workshop 1 – Introduction to MSC.Patran Model Description In this exercise you will create an analytic solid model of a clevis by defining MSC/PATRAN points, curves, surfaces, solids, and a user defined coordinate system. Throughout this exercise you will become more familiar with the use of the MSC/PATRAN select menu. You will also be introduced to another viewing method and shown how to change your model’s render style. Shown below is a drawing of the model you will build and suggested steps for its construction.

Workshop 1 – Introduction to MSC.Patran Suggested Exercise Steps Open up a new database. Define user settings. Change the geometric preference to PATRAN 2 convention. Create geometry. Creating surfaces for the geometry model. Create the solids of the geometry model. Display the model.

Step 1. Open Up a New Data Create a new database named clevis.db. g f Create a new database named clevis.db. File / New. Enter clevis.db as the file name. Click OK. Choose Default Tolerance. Select MSC.Marc as the Analysis Code. Select Structural as the Analysis Type.

Step 2. Define User Setting a c d b From the Preferences menu, select Picking and complete the subordinate form as follows. Preferences/Picking… Select Entity for Single Picking. Select Enclose entire entity for Rectangle/Polygon Picking. Click Close. In this step you will define the majority of the user settings that you will use throughout these exercises, unless otherwise noted. These settings include your picking preferences which define how you use your cursor to pick entities off the screen.

Step 3. Change the Geometric Preference to PATRAN 2 Convention b c d The PARAN 2 Convention convention represents a special class of parameterized geometry known as parametic cubic. This option allows the user to create geometry that can be exported and imported into PATRAN 3 through PATRAN 2 neutral files and IGES files. Preferences/Geometry… Select PATRAN 2 Convention. For Solid Origin Location. Click Apply. Click Cancel.

Step 4. Create Geometry a Create a Point on the Inner Radius of the Hole in the Clevis. First, make the geometry labels visible by using the following toolbar icon. Click Show Labels. Geometry: Create / Point / XYZ. Enter [1,0,0] for Point coordinates List. Click Apply. Create / Curve / Revolve Enter 45 as Total Angle. Enter 0 as Offset Angle. Select the point on the screen for Point List. e f h g b c d Continue with the procedure, selecting the angle increments of 45 degrees, until the curve is revolved 180 degrees with four curves per point. To accomplish this, next select 45 degree in the Offset Angel, using the same point, followed by 90 then 135 degrees. Four curves can now be seen in the viewport.

Step 4. Create Geometry (Cont.) d h g f e c b a Use Curvlinear Transformation to create the outer radius of the lug by radially translating the curves that define a quarter of the hole. Create / Coord / 3 Point. Select Cylindrical for Type. Click Apply. Transform / Curve / Translate. Select Curvilinear in Refer. CF for Type of Transformation. Select newly created coord frame for Refer. Coordinate Frame. Enter <1,0,0> as Translation Vector. Select the two curves on the right for Curve List.

Step 5. Create Surfaces for the Geometry Model b a You have now created all the curves that you will need to complete your clevis model. Next, you will create the necessary surfaces for the model. You will start by creating a 4x2 surface that defines part of the upper half of the clevis body. Create / Surface / XYZ Enter <-4,2,0> as Vector coordinates List. Enter [-2,0,0] as Origin Coordinates List. Click Apply. Create / Surface / Curve Select 2 Curve for Option. Drag to select the two inner right curves for Starting curve List. <ctrl> click to select the two outer right curves for Ending Curve List. Select the lower left inner curve (Curve 4) for Starting Curve List. Select Edge icon. Select the right edge of the rectangular surface for Ending Curve List. e h g f k i j h g k i

Step 5. Create Surfaces for the Geometry Model (Cont.) b Click Curve. Select the remaining inner curve (Curve 3) for Starting Curve List. Click Two Points. Select the two points where the remaining curve should be located (Pts 8 and 10) d b a c

Step 6. Create Solids of the Geometry Model b a You will now use the Surfaces you have just created as patterns to define solids (3-dimensional entities). Create / Solid / Normal. Enter 0.25 as Thickness. Select all surfaces for Surface List. Click Iso 1 View.

Step 6. Create Solids of the Geometry Model (Cont.) b Create the lower half of the model by mirroring the solid. Transform / Solid / Mirror Click in the Define Mirror Plane Normal databox and click Frame Direction 2. Select second direction of original coord frame for Define Mirror Plane Normal. Select all solid for Solid List.

Step 6. Create Solids of the Geometry Model (Cont.) b d Create the remaining solids using the Translate method. Transform / Solid / Translate Enter <0, 0, -0.25> for Translation Vector. Enter 2 for Repeat Count. Select only the two left solids (solid 1 and 6) for Solid List. d

Step 6. Create Solids of the Geometry Model (Cont.) b d a f e c The final geometry model construction step is to translate copies of the solids which surround the hole. Click in the Translation Vector databox and click Base and Tip Points. Click View Corners to zoom in. Pick Point 10 then Point 40 as shown. Select Fit View to zoom out. Enter 1 as Repeat Count. Select all solids which surround the hole for Solid List. a

Step 7. Display the Model c b a Change the display to see the model without labels and without the wireframe view. Click Hide Labels. Click Hidden Line. Click Wireframe. File / Close