Sunday, 3 October 2010

solid model of the Spindle Base

Problem Description B

We will be creating a solid model of the Spindle Base shown in the following figure.

Geometry Generation

We will create this model by creating the base and the back and then the rib.

Create the Base

  1. Create the base rectangle
    WP X (XCORNER)WP Y (YCORNER)WIDTHHEIGHT
    00109102
  2. Create the curved edge (using keypoints and lines to create an area)
    • Create the following keypoints
      XYZ
      Keypoint 5-20820
      Keypoint 6-20200
      Keypoint 70820
      Keypoint 80200
      You should obtain the following:
    • Create arcs joining the keypointsMain Menu > Preprocessor > (-Modeling-) Create > (-Lines-) Arcs > By End KPs & Rad
      • Select keypoints 4 and 5 (either click on them or type 4,5 into the command line) when prompted.
      • Select Keypoint 7 as the center-of-curvature when prompted.
      • Enter the radius of the arc (20) in the 'Arc by End KPs & Radius' window
      • Repeat to create an arc from keypoints 1 and 6
      (Alternatively, type LARC,4,5,7,20 followed by LARC,1,6,8,20 into the command line)
    • Create a line from Keypoint 5 to 6Main Menu > Preprocessor > (-Modeling-) Create > (-Lines-) Lines > Straight Line
      L,5,6
    • Create an Arbitrary area within the bounds of the linesMain Menu > Preprocessor > (-Modeling-) Create > (-Areas-) Arbitrary > By Lines
      AL,4,5,6,7
    • Combine the 2 areas into 1 (to form Area 3)Main Menu > Preprocessor > (-Modeling-) Operate > (-Booleans-) Add > Volumes
      AADD,1,2
    You should obtain the following image:
  3. Create the 4 holes in the baseWe will make use of the 'copy' feature in ANSYS to create all 4 holes
    • Create the bottom left circle (XCENTER=0, YCENTER=20, RADIUS=10)
    • Copy the area to create the bottom right circle (DX=69)(AGEN,# Copies (include original),Area#,Area2# (if 2 areas to be copied),DX,DY,DZ)
    • Copy both circles to create the upper circles (DY=62)
    • Subtract the three circles from the main base(ASBA,3,ALL)
    You should obtain the following:
  4. Extrude the basePreprocessor > (-Modeling-) Operate > Extrude > (-Areas-) Along Normal
      The following window will appear once you select the area
    • Fill in the window as shown (length of extrusion = 26mm). Note, to extrude the area in the negative z direction you would simply enter -26.
    (Alternatively, type VOFFST,6,26 into the command line)

Create the Back

  1. Change the working planeAs in the previous example, we need to change the working plane. You may have observed that geometry can only be created in the X-Y plane. Therefore, in order to create the back of the Spindle Base, we need to create a new working plane where the X-Y plane is parallel to the back. Again, we will define the working plane by aligning it to 3 Keypoints.
    • Create the following keypoints
      XYZ
      #1001091020
      #10110920
      #102159102sqrt(3)/0.02

    • Align the working plane to the 3 keypointsRecall when defining the working plane; the first keypoint defines the origin, the second keypoint defines the x-axis orientation, while the third defines the orientation of the working plane.
      (Alternatively, type KWPLAN,1,100,101,102 into the command line)
  2. Create the back area
    • Create the base rectangle (XCORNER=0, YCORNER=0, WIDTH=102, HEIGHT=180)
    • Create a circle to obtain the curved top (XCENTER=51, YCENTER=180, RADIUS=51)
    • Add the 2 areas together
  3. Extrude the area (length of extrusion = 26mm)Preprocessor > (-Modeling-) Operate > Extrude > (-Areas-) Along Normal
    VOFFST,27,26
  4. Add the base and the back together
    • Add the two volumes togetherPreprocessor > (-Modeling-) Operate > (-Booleans-) Add > Volumes
      VADD,1,2
      You should now have the following geometry
      Note that the planar areas between the two volumes were not added together.
    • Add the planar areas together (don't forget the other side!)Preprocessor > (-Modeling-) Operate > (-Booleans-) Add > Areas
      AADD, Area 1, Area 2, Area 3
  5. Create the Upper Cylinder
    • Create the outer cylinder (XCENTER=51, YCENTER=180, RADIUS=32, DEPTH=60)Preprocessor > (-Modeling-) Create > (-Volumes-) Cylinder > Solid Cylinder
      CYL4,51,180,32, , , ,60
    • Add the volumes together
    • Create the inner cylinder (XCENTER=51, YCENTER=180, RADIUS=18.5, DEPTH=60)
    • Subtract the volumes to obtain a hole
    You should now have the following geometry:

Create the Rib

  1. Change the working plane
    • First change the active coordinate system back to the global coordinate system (this will make it easier to align to the new coordinate system)Utility Menu > WorkPlane > Align WP with > Global Cartesian(Alternatively, type WPCSYS,-1,0 into the command line)
    • Create the following keypoints
      XYZ
      #200-206126
      #20106126
      #202-206130

    • Align the working plane to the 3 keypointsRecall when defining the working plane; the first keypoint defines the origin, the second keypoint defines the x-axis orientation, while the third defines the orientation of the working plane.
      (Alternatively, type KWPLAN,1,200,201,202 into the command line)
  2. Change active coordinate systemWe now need to update the coordiante system to follow the working plane changes (ie make the new Work Plane origin the active coordinate)
    Utility Menu > WorkPlane > Change Active CS to > Working Plane
    CSYS,4
  3. Create the area
    • Create the keypoints corresponding to the vertices of the rib
      XYZ
      #203129-(0.57735*26)00
      #204129-(0.57735*26) + 38sqrt(3)/2*760

    • Create the rib area through keypoints 200, 203, 204Preprocessor > (-Modeling-) Create > (-Areas-) Arbitrary > Through KPs
      A,200,203,204
  4. Extrude the area (length of extrusion = 20mm)
  5. Add the volumes together
You should obtain the following:

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