03-02ChapGere.0015

03-02ChapGere.0015 - diameter. The shaft must transmit 400...

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Problem 3.7-4 The drive shaft for a truck (outer diameter 60 mm and inner diameter 40 mm) is running at 2500 rpm (see figure). (a) If the shaft transmits 150 kW, what is the maximum shear stress in the shaft? (b) If the allowable shear stress is 30 MPa, what is the maximum power that can be transmitted? Solution 3.7-4 Drive shaft for a truck 218 CHAPTER 3 Torsion 60 mm 2500 rpm 60 mm 40 mm d 2 5 60 mm d 1 5 40 mm n 5 2500 rpm (a) M AXIMUM SHEAR STRESS t max P 5 power (watts) P 5 150 kW 5 150,000 W T 5 torque (newton meters) n 5 rpm . T 5 60(150,000 W) 2 p (2500 rpm) 5 572.96 N . m P 5 2 p nT 60 Ê T 5 60 P 2 p n I P 5 p 32 ( d 2 4 2 d 1 4 ) 5 1.0210 3 10 2 6 m 4 (b) M AXIMUM POWER P max 5 267 kW Ê P max 5 P t allow t max 5 (150 kW) ¢ 30 MPa 16.835 MPa t allow 5 30 MPa t max 5 16.8 MPa Ê 5 16.835 MPa t max 5 Td 2 2 I P 5 (572.96 N . m)(0.060 m) 2(1.0210 3 10 2 6 m 4 ) Problem 3.7-5 A hollow circular shaft for use in a pumping station is being designed with an inside diameter equal to 0.75 times the outside
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Unformatted text preview: diameter. The shaft must transmit 400 hp at 400 rpm without exceeding the allowable shear stress of 6000 psi. Determine the minimum required outside diameter d . Solution 3.7-5 Hollow shaft d 5 outside diameter d 5 inside diameter 5 0.75 d H 5 400 hp n 5 400 rpm t allow 5 6000 psi T ORQUE H 5 2 p nT 33,000 I P 5 p 32 [ d 4 2 (0.75 d ) 4 ] 5 0.067112 d 4 H 5 hp n 5 rpm T 5 lb-ft M INIMUM OUTSIDE DIAMETER d 3 5 78.259 in. 3 d min 5 4.28 in. 0.067112 d 4 5 (63,025 lb-in.)( d ) 2(6000 psi) t max 5 Td 2 I P I P 5 Td 2 t max 5 Td 2 t allow 5 5252.1 lb-ft 5 63,025 lb-in. T 5 33,000 H 2 p n 5 (33,000)(400 hp) 2 p (400 rpm) A-PDF Split DEMO : Purchase from www.A-PDF.com to remove the watermark...
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