. Railway mechanical engineer . (D X 1) + (b XWX- \( 40,0(10 ■ II-, )_ V + 608,000- = 639,700- = Mi. or bending moment. — 163,000 = Mi or twisting moment. 14 14 According to Rankin the equivalent bending momentwhen Mo is greater than M« = 639,700_■ Mi. f V Mu= -f Mi3 nr -r V 639,700= + 163,000 979,050 Mm; r the combined bending and twisting moment in inch-pounds. The fiber stress becomes 979,050 13,700 lb.; oi for a 91 -in. axle = 11 500 lb d3 x :III. F. J. Coles method given in the American Engi-. Diagram for Use with Method 1 ui,r, April 1898, page 124, usin
. Railway mechanical engineer . (D X 1) + (b XWX- \( 40,0(10 ■ II-, )_ V + 608,000- = 639,700- = Mi. or bending moment. — 163,000 = Mi or twisting moment. 14 14 According to Rankin the equivalent bending momentwhen Mo is greater than M« = 639,700_■ Mi. f V Mu= -f Mi3 nr -r V 639,700= + 163,000 979,050 Mm; r the combined bending and twisting moment in inch-pounds. The fiber stress becomes 979,050 13,700 lb.; oi for a 91 -in. axle = 11 500 lb d3 x :III. F. J. Coles method given in the American Engi-. Diagram for Use with Method 1 ui,r, April 1898, page 124, using the same symbols and figures as for previous illustrations: 1. Fiber stress from bending moment due to piston thrust,— P X 1 70,000 X 22 10,800 lb. load,- f. -. = 2 x R 2 x ( = R. for 9-in. axle) Fiber =tress from bending moment due to dead 32,000 X 10 = 2,240 lb. 2 X Combining to arrive at the resultant f. s. \ + 2,240= = 11,020 lb. For the torsional stress the force of the piston is dividedequally between the driving axles. In the illustration usedthere are four driving axles. We then have A P X r 70,000 X 13 - = - 1,580 lb. 4 • R 8 X Mr. Cole assumes that one-half of this quantity is themaximum torsional stress likely to occur at any one we have 1,580 -=- 2 = 7W lb. rhe stress due to centrifugal force = W X V 40,000 • = 7,000 X radius of curve X 955 The lever arm = T/> the diameter of the drivers = 28^4in. and the fiber stress due to centrifugal force =
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroadengineering
