261_Mechanics SolutionInstructors_Sol.Manual-Mechanics_Materials_7e.book_Gere_light.1

261_Mechanics SolutionInstructors_Sol.Manual-Mechanics_Materials_7e.book_Gere_light.1

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SECTION 3.3 Circular Bars and Tubes 255 Problem 3.3-5 A high-strength steel drill rod used for boring a hole in the earth has a diameter of 0.5 in. (see figure). The allowable shear stress in the steel is 40 ksi and the shear modulus of elasticity is 11,600 ksi. What is the minimum required length of the rod so that one end of the rod can be twisted 30° with respect to the other end without exceeding the allowable stress? d = 0.5 in. T T L Solution 3.3-5 Steel drill rod G ± 11,600 psi d ± 0.5 in. ² allow ± 40 ksi M INIMUM LENGTH From Eq. (3-12): (1) t max ± 16 T p d 3 f ± 30° ± (30°) a p 180 b rad ± 0.52360 rad From Eq. (3-15): L min ± 38.0 in. ; ± (11,600 ksi)(0.5 in.)(0.52360 rad) 2(40 ksi) L min ± Gd f 2 t
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Unformatted text preview: allow t max a 16 p d 3 ba G p d 4 f 32 L b Gd f 2 L T G p d 4 f 32 L , substitute T into Eq. (1): f TL GI P 32 TL G p d 4 d = 0.5 in. T T L Problem 3.3-6 The steel shaft of a socket wrench has a diameter of 8.0 mm. and a length of 200 mm (see figure). If the allowable stress in shear is 60 MPa, what is the maximum permissible torque T max that may be exerted with the wrench? Through what angle (in degrees) will the shaft twist under the action of the maximum torque? (Assume G 78 GPa and disregard any bending of the shaft.) L = 200 mm d = 8.0 mm T Sec_3.3.qxd 9/27/08 1:27 PM Page 255...
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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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