Practice-Exam1-1

# Practice-Exam1-1 - Element 1 undergoes temperature change...

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Name: 1 AAE 352: Practice Exam Problem 1 A hoist assembly (motor and cable) mounted on a light weight structure weighs 60 pounds. This frame is designed to lift 1000 pounds with a maximum acceleration of 15 ft/sec 2 . Only the weight is accelerating: the truss assembly and hoist are stationary. (a) Compute the tension in the cable at this acceleration (b) Compute the reaction forces at the supports, A and D. Neglect the weight of the truss structure itself. (c) Compute the internal loads in elements BC and CE due to the 60 pound hoist and the accelerating 1000 pound mass. (d) Identify whether element BC is in tension or compression. Identify whether element CE is in tension or compression. (e) In an optimized structure (i.e. designing each member for minimum weight based on its probable mode of failure), which member will weigh more, BC or CE? Give a simple reason why. Cable

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Name: 2 Problem 2 Two fixed members are connected as shown.
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Unformatted text preview: Element 1 undergoes temperature change ∆ T 1 and Element 2 undergoes temperature change ∆ T 2 . (a) Find the displacement of the center node caused by this temperature difference ∆ T 1 and ∆ T 2 in terms of the parameters A 1,2 , E 1,2 , L 1,2 , α 1,2 , ∆ T i . (b) The temperature difference is now removed (everything is back at the temperature where it started so there are no thermal stresses) and replaced by a mechanical force. What is the magnitude of the force that would need to be applied at the center node to cause the elements to experience the same stresses they experienced during the thermal loading? Express the force in terms of the parameters in terms of the parameters A 1,2 , E 1,2 , L 1,2 , α 1,2 , ∆ T i . ( Hint: this question does not require significant additional manipulation ). A 1 , E 1 , L 1 , α 1 A 2 , E 2 , L 2 , α 2 Element 1 Element 2 P...
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Practice-Exam1-1 - Element 1 undergoes temperature change...

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