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| Executive Summary | ||
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Vibrations induced by unbalanced rotating machinery are a problem throughout many industries, and because of this it is important that students in mechanical engineering vibration laboratories have a strong hands-on working knowledge of this phenomenon. The goal of this project is to provide a visual, measured response to unbalanced rotations in a controlled undergraduate laboratory setting. An experiment will also be designed and added to the student lab manual to instruct the students in the correct usage of the equipment. The primary phase of design has been completed, and the documentation of the project is an ongoing process. The third phase, creation, will be completed 2 weeks before the deadline for the project. This phase consisted of ordering materials and parts, machining and assembly of the test stand, testing, and refinements. During this time, the experiment procedure will be written. The last phase, final documentation, will be completed by 4/27/06, and will consist of the final project report, this website and poster for the showcase. The estimated total cost of our project is $800.00. This figure includes all hardware, materials, and components. It also includes miscellaneous expenses, including presentation materials, and other unknown items. |
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| Objectives | ||
| The objective of the specified assignment, as given by the sponsor, Dr. Trethewey, is to illustrate rotating unbalance for the undergraduate Vibrations Laboratory at Penn State University. The vibrations induced by the unbalance must be visually observable by the students. The stand must also have adequate safety devices (shielding, grounding, etc.) and run from existing 110 V AC electric outlets. The entire stand must fit in existing desk drawers that measure approximately 12" by 18" with a height of 12", as shown in the below figure. | ||
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| Overall Design | ||
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The decision of how to design the equipment to cater to the overall objectives of the project was accomplished through a decision map and matrix. The study of feasibility of the test stand design will be accomplished through several tools and techniques. Software packages that will be utilized include MATLAB in combination with SigLAB. This will be accomplished via a dedicated SigLAB Input/Output controller. Also, SolidWorks was used for analysis, design and machining purposes. Inputs into the SigLAB controller include, but are not limited to, an accelerometer placed on the test stand. Due to the general nature of the problem statement, the choice of the best overall method of study is made by the pros and cons of each part of the decision map and matrix. The pros and cons of several general categories within the decision map were broken down to make a final selection. Final design selectionis shown in the images below. |
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| Design Performance Evaluation | ||
The evaluation will start with a spring constant of 200 lb/in, then data will be tabulated using the variables listed below. The design leaves room for a very heavy unbalance, concentration will be placed on a small unbalance to emphasize the potential devastating effects of small rotating unbalance. Variables: Result: The natural frequency lies in the middle of the total motor operating range. In other words, to operate at speeds higher than the natural frequency, the motor needs to speed past the natural frequency, much like a jet engine. |
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