150_Mechanics SolutionInstructors_Sol.Manual-Mechanics_Materials_7e.book_Gere_light.1

# 150_Mechanics SolutionInstructors_Sol.Manual-Mechanics_Materials_7e.book_Gere_light.1

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Unformatted text preview: Sec_2.4.qxd 144 9/25/08 11:38 AM Page 144 CHAPTER 2 Axially Loaded Members EAAAP + 4EAAAW 5EAAA + ES AS RSL AS 3EAAAP + PESAS + 2EAAAW + 2WESAS 10EAAA + 2ESAS PSa 2RA P +W 2 sSaAS a PSa sSa P +W 2 RSR RSR RSR 10sSaASEAAA + 2 sSaA S E S 6EAAA + ESAS 10EAAA + 2ESAS b 6EAAA + ESAS 4EAAAW 6EAAA + ESAS 2 4EAAAW PSa 703 N ^ steel controls ; Problem 2.4-13 A horizontal rigid bar of weight W 7200 lb is supported by three slender circular rods that are equally spaced (see figure). The two outer rods are made of aluminum (E1 10 106 psi) with diameter d1 0.4 in. and length L1 40 in. The inner rod is magnesium (E2 6.5 106 psi) with diameter d2 and length L2. The allowable stresses in the aluminum and magnesium are 24,000 psi and 13,000 psi, respectively. If it is desired to have all three rods loaded to their maximum allowable values, what should be the diameter d2 and length L2 of the middle rod? Solution 2.4-13 Bar supported by three rods BAR 1 ALUMINUM 106 psi E1 10 d1 0.4 in. L1 FREE-BODY DIAGRAM OF RIGID BAR EQUATION OF EQUILIBRIUM 40 in. 1 Fvert 2F1 0 F2 W 0 (Eq. 1) FULLY STRESSED RODS 24,000 psi F1 1A1 F2 2A2 BAR 2 MAGNESIUM E2 6.5 106 psi d2 ? L2 2 13,000 psi ? A1 Substitute into Eq. (1): 2s1 a pd2 1 4 b + s2 a pd2 2 4 b W pd2 1 4 A2 pd2 2 4 ...
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## This note was uploaded on 12/22/2011 for the course MEEG 310 taught by Professor Staff during the Fall '11 term at University of Delaware.

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