SolidWorks Tutorial 3D Trusses (1)

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3D Solidworks Simulation;

Text of SolidWorks Tutorial 3D Trusses (1)

  • Introduction to SolidWorks 3D Truss Simulation MAE 292 Spring 2014 Professor Frank Talke

    Created for SolidWorks 2014

    I. Create Geometry 1. Create a New Part a. Change units to meters. 2. Use Weldments a. Under the Weldments tab select 3D sketch. i. If the Weldments tab is not visible, right click any tab on that same bar and then check Weldments.

  • b. Lay floor dimensions with Construction-lines/ Centerlines on the XZ plane .

    i. Notice you can initially sketch in XY, YZ and ZX planes (use tab key to toggle). ii. Below is the same sketch with different views. It is important that you are on the XZ plane. When sketching, it may be easier to orient yourself normal to the sketch plane as seen on the left.

    c. Create one more construction. Sketch a vertical line in the YZ plane of 4 meters starting at point (5,0,3) moving towards point A, (5,4,3).

  • d. Sketch in the YZ plane a vertical (non-construction) line that is 2 meters in length. This line should be from point E (0,0,3) to point B (0,2,3).

    e. Now, using the line tool with any plane on the cursor, you will be able to sketch unrestricted to these 3 offered planes by connecting the proper points that you have created already. Do this to complete the sketch as seen below.

    f. Exit the sketch by either reselecting the 3D sketch tool within the Weldments command bar or by select the return from sketch button shown below.

  • 3. Use Weldments to Create the Truss Structure a. Under the Weldments tab and in the command bar, select Structural Member.

    b. We will use the standard selections for now and change the sketch shortly after we create all groups.

    c. Select the two 3D lines shown which will create Group 1.

  • d. Select new group, and then select the 4 other lines shown below. Finally, select green check mark.

    e. Change cross section for Weldment i. In the Design Tree, expand your Structural Member, then right click Sketch and select Edit Sketch.

  • ii. Orient yourself to the sketching plane.

    iii. Zoom in on the sketch, and delete all lines and points (can use the control button or select chain). If the Sketcher Confirm Delete popup window appears, select Yes to all.

    iv. Once the initial sketch is deleted, sketch a 0.0075m x 0.0075m square about the same center point / origin as the original sketch. Then exit the sketch.

  • v. Notice that you now have the proper cross section to perform the truss analysis. (a full scale and zoomed in picture are shown, so you are not surprised by the results).

    II. Begin Simulation a. You may want to review SolidWorks Tutorial 6 (FEA on the Brace) before moving forward. b. Start a simulation by ensuring that the simulation tab is available. You may need to select SolidWorks Simulation button under the Office Products tab or go to add-ins in the tools menu.

    1. Start a New Study a. Choose Static study and label the new study Truss Study 1.

  • a. With Weldments, SolidWorks Simulation already assumes that you are performing a beam analysis, noticing the nodes already created.

    b. Expanding Part1 in the Simulation Tree, select / highlight each SolidBody. Then, right click and select Edit Definition.

  • c. Select Truss as shown below. Then select the green check mark. Now you can see that the shape of the bar next to each SolidBody, indicates that we are working with trusses instead of beams.

    d. Create the Joint Group. (Even though we have the joints already selected it is important to know that we can recalculate where the joints are if necessary.) i. Right click Joint group in the Simulation Tree and select edit.

    ii. Select Calculate. A warning may appear stating that if you have any boundary conditions already applied, each boundary condition uses a old node/joint numbering system. The recalculation may change the number system. (If you already applied any boundary conditions, delete them and reapply ensuring that the right numbering system is used.)

  • 2. Apply Material a. Select Apply Material in the simulation command bar, and select Alloy Steel as our material.

    3. Apply Constraints / Fixtures a. From the pull down bar below Fixture Advisor, select Fixed Geometry. Select the three joints as shown below and ensure that Fixed Geometry is selected. Finally select the green check mark. (Here we increased that magnitude of the symbol under Symbol Settings to make the constraints more visible.)

  • 4. Apply Forces / Loads a. From the pull down bar below External Loads Advisor, select Force.

    b. In the Force / Torque window. i. Select the Joints/Node button in the Selection window and with that window next to it highlighted select the joint/node we would like apply the force to. ii. Still in the Selection Pane but highlighting the reference plane/surface box, select the Right Plane in the Design Tree (or whichever plane is perpendicular to the force we want to apply). iii. In the Force window, select the icon that shows an arrow pointing perpendicular to the plane and apply a 6000 newton force. (Again an adjustment was made in Symbol Settings to make the force more visible in the graphics window). iv. Select the green check mark to accept.

  • 5. Create the Mesh a. Create the mesh by selecting the pull down menu below Run and then selecting Create Mesh.

    b. Creating mesh: Since we defined all bodies as trusses, there are no options for meshing. So it automatically creates the Mesh filled only with these trusses. The only visual difference is that if you zoom in you can see that your weldment cross sections have disappeared and the model is now showing its form of a generic truss mesh. Thinking of the stiffness matrix, K, we have 3 displacement degrees of freedom at each node for 5 nodes, which results in a 15x15 stiffness matrix. Each Truss only needs the values including the Elastic Modulus (E-from materials), Cross Section Area (A-from defined sketch in weldments), Length (L-from geometry/ 3D-Sketch), and the orientation angles.

    6. Run the Simulation a. Think about the reduced K matrix. Constraining 3 of the 5 nodes results in a final 6x6 reduced stiffness Matrix, Kred that is needed to solve the [Kred]{dred} = {fred} equation.

  • 7. Analyze Results i. Delete Default Plots. b. Add an Axial Stress Plot i. Right click Results in the Simulation Tree and select Define Stress Plot. In the Stress Plot Window change the option to Axial as shown below and click the green check mark.

    ii. To see the visual axial stress results of each truss, you may need to zoom in on the truss structure. Knowing that axial stress in a truss will be constant we can zoom into each of the top 2 corners and see the related color for all truss elements in structure.

  • iii. Now use the probe tool, found by right clicking on the stress plot in the simulation tree. Select each element and then plot your results. Take a screen shot of this image including all probed elements with the time stamp from the properties window to turn in for your homework.

  • c. Add an X Displacement Plot i. Right click Results in the simulation tree and select Define Displacement Plot. ii. In the Displacement Plot Window change the option to UX: X Displacement as shown below and Click the green check mark.

    iii. You will see displacement vary linearly along the beam. To see how far the joint / node moves at point A use the probe tool and select on the joint / node. This will show you how far the node will move in the x direction in millimeters. Take a screen shot of this image

    including the probed node with the time stamp from the properties window to turn in for your homework.