San Antonio, Texas
June 10, 2012
June 10, 2012
June 13, 2012
25.142.1 - 25.142.9
Title: Torsional Pendulum CharacterizationDate: Oct 3, 2011Test Engineer:Hugh JackPurpose (Objective): To determine the predictability of a torsional pendulum’s frequency of oscillation.Background: Torsional pendulums consist of i) a torsional spring, ii) an inertial mass. The torsional spring used here will be a thin metal rod. The inertial mass will be a long beam section. Figure 1 Experimental setup for torsional pendulumThe torsional spring coefficient is a function of the rod length, diameter, and shear modulus.The moment of inertia for the mass is.... Mr^2 / 12 Figure 2: Cross-section of pendulum mass (this should be a rectangle, not a circle)Summing the torques gives the following Diff. Eqn.….....Solving the Diff. Eqn. results in a natural frequency of __. Solving the differential equationresults in an equation of...Equipment List: 1. Parallax Propeller Demo Board Rev. G 2008 2. Tape Measure 3. Ping))) Ultrasonic Sensor 28015 Rev. A 2005 4. Laptop 5. Calipers 6. Calculator 7. 1020 cold rolled steel pendulum assembly 8. MIG Welder 9. 8” C-Clamps (registration number) 10. Stand for sensor 2” high 11. StopwatchProcedure: (always third person) 1. The pendulum was hung from a table edge to allow a clearance of 2 inches from the floor. C-Clamps were used to hold the pendulum firmly. 2. The dimensions of the pendulum were taken and used to estimate the frequency of oscillation. Diameter of spring = (these are different for both groups) Length of Spring = Mass width = Mass length = Mass height = G Spring = M Mas 3. To verify the frequency of oscillation the pendulum was deflected approximately 2 inches. When released a cellphone timer was started. After 20 oscillations the time was stopped. The frequency was found by timing XX oscillations with a cell phone stopwatch. The for these oscillations took XX seconds. 4. A program was written for the Propeller controller to measure distance using the ultrasonic sensor. The electrical connections are shown in Figure 3, the source code for the program is in Appendix A. Figure 3 - Schematic for Ultrasonic Measurement 5. Results section: compare frequency (calculated and measured)Discussion Section---------> here you compare the expected and actual results. You will repeat some of the majorpoints in the conclusions.Conclusion section----> you must indicate how the results support the purpose/objective. For this I expect that youwill indicate that similar experiments or designs can be expected to be within a certain range.e.g. +/- a percentage.
Barger, M., & Gilbert, R., & Owens, E. (2012, June), Aligning Florida's Manufacturing Programs with External Standards: Closing the Loops Paper presented at 2012 ASEE Annual Conference & Exposition, San Antonio, Texas. https://peer.asee.org/20902
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