MSC.visualNastran 4D Exercise Workbook Small Ball with Large Velocity

Objectives Exercise Overview This… Set up for the simulation. Create a sphere. Create a ground plane. Run the simulation. Adjust the simulation settings. Re-run the simulation.

I - Set Up Pick the Display Settings tool in the toolbar to open the “Settings” dialog box. Go to the Units option. Change the “Unit System” to “English(pounds)”. (Figure 1) The Unit of this model will be in English(pounds). If you change the unit system after a model is built, the existing dimensions of the model will be converted to the new unit system. Click “Close” to close the “Settings” dialog box. Figure 1 Settings – Units

II - Create a Sphere Click the Sphere tool in the toolbar once. Notice a drawing grid appears in the simulation window. Click anywhere on the drawing grid to assign the center of the sphere. Drag the sphere out until the radius is close to 0.5 in. To check the radius of the sphere, look at the dimension box below the playback toolbar. (Figure 2) Left-click once to finalize the sphere. (Figure 3) The position and velocity will be assigned later. Figure 3 Sphere Figure 2 Dimension Box

II - Create a Sphere Double-click the sphere to open its “Properties” dialog box. You can double-click the sphere either in the simulation window or the Object Browser. In the Object Browser, the sphere will have a sphere icon next to it and it will be labeled “body[1]”, since it is the first body created. Pick the Appearance tab and enter the name “Sphere”. Go to the Position tab and enter (0,0,3) in the X, Y, and Z position fields. (Figure 4) This moves the “Sphere” 3 inches above the World coordinate origin. The model is updated instantaneously. Go to the Velocity tab and enter –200 in/sec in the Vz field. (Figure 5) There is now a velocity of -200 inches per second in the z-direction. Go to the Sphere tab and enter .5 in the “Radius” field. The radius is now manually adjusted to be .5 inches. Click “Close” to close the “Properties” dialog box. Figure 4 Position Tab Figure 5 Velocity Tab

III - Create Ground Plane Pick Insert>Ground Plane. (Figure 6) A Ground Plane of arbitrary size will be placed in the simulation window. If needed, strike V on the keyboard to re-size the view so both the “Sphere” and “Ground Plane” are visible in the simulation window. Double-click the “Ground Plane” and go to the Box tab. Enter the values (3,3,0.1) for X, Y, and Z. (Figure 7) The “Ground Plane’s” dimensions instantly change. Click “Close” to close the “Properties” dialog box. Figure 6 Ground Plane Figure 7 Box Tab

IV - Run Simulation Click “Run” to run the simulation. The “Sphere” penetrates through the ground plane and drops out of the simulation window. Click “Stop” once the “Sphere” is no longer visible in the simulation window. Click “Reset” to reset the simulation. It is a good habit to always reset the simulation after running it. Click the “Step” forward button once. Notice the “Sphere” disappears almost immediately. Also notice that only .02 seconds passed. (Figure 8) Use the Zoom In/Out and Pan tools to zoom out so the “Sphere” can be seen. The simulation after the first frame is shown in Figure 9. The velocity of the sphere is so large that it drops below the ground plane very quickly. Don’t forget to reset the simulation before moving on to the next step. Figure 8 First Frame Figure 9 Simulation After First Frame

V - Simulation Setting Because the velocity of the Sphere is so large, you must either slow down the simulation rate or slow down the Sphere’s velocity. From the World menu, select Simulation Settings, or click on the Simulation Settings tool. Pick the Integration option under the Simulation Settings tree. Change the “Animation Frame Rate” to 250 frames per second and click “Apply”. (Figure 10) The “Time” in the “Animation Frame Rate” will be updated automatically. Click “Close” to close the “Settings” dialog box. Figure 10 Integration Tab

VII - Re-Run Simulation Holding the Control key down, select the “Ground Plane” and the “Sphere”. (Figure 11) Right-click on either body and choose Collide. (Figure 12) Now the two objects will collide with each other. Re-Run the simulation. You will notice that the ball does not immediately disappear. “Reset” the simulation. Click “Step Forward” or move around the “Run Control Slider” to see the “Sphere’s” motion. The “Sphere” disappears after the 15th frame and returns in the 124th frame. This exercise is now complete. Figure 11 Simulation Settings - FEA Figure 12 Simulation Settings - FEA