01-02ChapGere.0006

01-02ChapGere.0006 - What is the allowable value of the...

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SECTION 1.7 Allowable Stresses and Allowable Loads 37 Solution 1.6-15 Shock mount r 5 radial distance from center of shock mount to element of thickness dr (a) S HEAR STRESS t AT RADIAL DISTANCE r A s 5 shear area at distance r Steel tube Rubber cylinder dr r d b d P b h d 5 2 p rh (b) D OWNWARD DISPLACEMENT d g 5 shear strain at distance r d d 5 downward displacement for element dr d 5 P 2 p hG ln b d b / 2 d / 2 d 5 P 2 p hG # b @ 2 d @ 2 dr r 5 P 2 p hG [ln r ] d 5 # d d 5 # b @ 2 d @ 2 Pdr 2 p rhG d d 5 g dr 5 Pdr 2 p rhG g 5 t G 5 P 2 p rhG t 5 P A s 5 P 2 p rh Allowable Stresses and Allowable Loads Problem 1.7-1 A bar of solid circular cross section is loaded in tension by forces P (see figure). The bar has length L 5 16.0 in. and diameter d 5 0.50 in. The material is a magnesium alloy having modulus of elasticity E 5 6.4 3 10 6 psi. The allowable stress in tension is s allow 5 17,000 psi, and the elongation of the bar must not exceed 0.04 in.
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Unformatted text preview: What is the allowable value of the forces P ? d P P L Solution 1.7-1 Magnesium bar in tension L 5 16.0in. d 5 0.50in. E 5 6.4 3 10 6 psi s allow 5 17,000 psi d max 5 0.04 in. M AXIMUM LOAD BASED UPON ELONGATION e max 5 d max L 5 0.04 in. 16 in. 5 0.00250 s max 5 E e max 5 (6.4 3 10 6 psi)(0.00250) 5 16,000psi M AXIMUM LOAD BASED UPON TENSILE STRESS A LLOWABLE LOAD Elongation governs. P allow 5 3140lb 5 3340 lb P max 5 s allow A 5 (17,000 psi) ¢ p 4 ≤ (0.50 in.) 2 5 3140 lb P max 5 s max A 5 (16,000 psi) ¢ p 4 ≤ (0.50 in.) 2 d P P L A-PDF Split DEMO : Purchase from www.A-PDF.com to remove the watermark...
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This note was uploaded on 09/20/2009 for the course COE 3001 taught by Professor Armanios during the Spring '08 term at Georgia Tech.

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