MEEN 225: Project 2-MEEN225: EQUILBRIUM OF A SINGLE RIGID BODY

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Project Overview In this project we will analyze the forces produced when raising a load using three-cable rigging system similar to Figure 1. In our situation, we will study a case where the load... may shift position within the load basket, and how load position affects the tensions developed in the rigging system The objective of the analysis will be to determine the realized Factor of Safety (FoS) for the rigging cables. The realized factor of safety is a measure of how close the working loads of a system are to the failure point of the system. A realized factor of safety for a rigging cable can be calculated by: Project Objectives By doing the project, students should be able to: • Apply equations of equilibrium to solve for unknown forces for a point mass in three dimensions • Determine the orientation of an single rigid body suspended at a point above it center of gravity • Introduce coordinate system to geometric model of real system • Represent geometrical parameters and forces present in real system in terms of coordinate system selected • Identify most limiting case for underspecified loading condition • Determine a realized factor of safety for prescribed situation TASK 1: Construct a physical demonstration To begin the project, the first task will be to construct a simple demonstration model of a three cable rigging system geometrically similar to the situation to be studied in tasks 2 & 3. What you will need for your demonstration model are: 1. A cardboard box with an open top. Recommended dimensions are a square base six inches by six inches, and a having a height of three inches. Figure 2 provides a template for constructing such a box from a one-foot square section of cardboard. 2. Three pieces of fishing line with closed loops on both ends and having equal lengths of approximately ten inches. Actual length is not critical for the model, but the length of the three lines must be equal. 3. Four paper clips bent so the form of an ‘S’ hook. 4. A full 12 oz. can of soda TASK 2: Model and analyze actual system-load centered. Based on the information provided for the components of the actual system, determine the realized Factor of Safety (FoS) assuming that the drum is upright with axis at the center of the lifting basket. Your work for this task should include: 1. A free body diagram(s) of the system(s) analyzed. 2. A geometric diagram showing coordinate system and component dimensions. 3. Equations for equilibrium of the system analyzed. 4. Tension in each cable. 5. Realized Factor of Safety. TASK 3: Model and analyze actual system-load shifted. Repeat the analysis of Task 2 assuming that the drum is now shifted to the corner position of the load basket. Which factor of safety, Task 2 or Task 3, should be used for evaluating the risk of actual working conditions? Explain your reasoning for your selection. [Show More]

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