05-05ChapGere.0009

05-05ChapGere.0009 - height h 5 1.25 in., what is the...

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Solution 5.12-2 Aluminum pole for a street light 358 CHAPTER 5 Stresses in Beams W 1 5 weight of pole 5 4600 N W 2 5 weight of arm 5 660 N b 5 distance between axis of pole and center of gravity of arm 5 1.2 m d 2 5 outer diameter of pole 5 225 mm d 1 5 inner diameter of pole 5 225 mm 2 2(18 mm) 5 189 mm A T BASE OF POLE P 5 W 1 1 W 2 5 5260 N M 5 W 2 b 5 792 N ? m P ROPERTIES OF THE CROSS SECTION M AXIMUM STRESSES 52 0.4493 MPa 1 1.4105 MPa 5 0.961 MPa 5 961 kPa 52 1.860 MPa 52 1860 kPa s c 52 P A 2 Mc I 52 0.4493 MPa 2 1.4105 MPa s t 52 P A 1 Mc I 52 5260 N 11,706 mm 2 1 (792 N ? m)(112.5 mm) 63.17 3 10 6 mm 4 c 5 d 2 2 5 112.5 mm I 5 p 64 ( d 4 2 2 d 4 1 ) 5 63.17 3 10 6 mm 4 A 5 p 4 ( d 2 2 2 d 2 1 ) 5 11,706 mm 2 d 2 P M Problem 5.12-3 A curved bar ABC having a circular axis (radius r 5 12 in.) is loaded by forces P 5 400 lb (see figure). The cross section of the bar is rectangular with height h and thickness t . If the allowable tensile stress in the bar is 12,000 psi and the
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Unformatted text preview: height h 5 1.25 in., what is the minimum required thickness t min ? Solution 5.12-3 Curved bar 45 45 B P P A C h r h t r 5 radius of curved bar e 5 r 2 r cos 45 C ROSS SECTION h 5 height t 5 thickness A 5 ht S 5 1 6 th 2 M 5 Pe 5 Pr 2 (2 2 2 ) 5 r 1 2 1 2 T ENSILE STRESS M INIMUM THICKNESS S UBSTITUTE NUMERICAL VALUES : P 5 400 lb s allow 5 12,000 psi r 5 12 in. h 5 1.25 in. t min 5 0.477 in. t min 5 P h s allow B 1 1 3(2 2 2 ) r h R 5 P ht B 1 1 3(2 2 2 ) r h R s t 5 P A 1 M S 5 P ht 1 3 Pr (2 2 2 ) th 2 B P P A e M A-PDF Split DEMO : Purchase from www.A-PDF.com to remove the watermark...
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