. Railway age gazette . gth. This shows the tendencyof the shell or joint to pull apart when the boiler is under steampressure. Now suppose a hole be drilled at each end of the longitudinaldistance />, as in Fig. 2. We can readily see that the force upon plate of unknown strength, and 45,000 ^ 4, or lb. per , for iron plate of unknown strength. As an example let us assume that we have a boiler with thefollowing dimensions; P = 175 lb.; D = 60 in.; i? = 30 in.;( = in.; p (pitch of outside row of rivets in seam or patch)= 3 in.; and d (diameter of rivet holes) = 13/16 in. (0.
. Railway age gazette . gth. This shows the tendencyof the shell or joint to pull apart when the boiler is under steampressure. Now suppose a hole be drilled at each end of the longitudinaldistance />, as in Fig. 2. We can readily see that the force upon plate of unknown strength, and 45,000 ^ 4, or lb. per , for iron plate of unknown strength. As an example let us assume that we have a boiler with thefollowing dimensions; P = 175 lb.; D = 60 in.; i? = 30 in.;( = in.; p (pitch of outside row of rivets in seam or patch)= 3 in.; and d (diameter of rivet holes) = 13/16 in. (). The stress acting for distance p will be equal to 175 X 30X 3 = 15,750 lb. The net section of plate will be equal to(/, _ rf) X < = (3 — ) X = sq. in. Dividingthe net section in square inches into the stress, we have the ten-sion per square inch, thus: 15,750 -^ 1,093 = 14,409 lb. per sq. c/= D/am. of Rivet Ho/e p = Pifch ofRi/efs t = Thickness ofP/afe Cp-d) X t = Net Secf/on ofP/afe K-d-H. Fig. 2—Different Conditions After Drilling Holes in., which is too high, giving a factor of safety of 50,000 -f- 14,409=r , instead of 4 as required by law. .Assuming that this is a seam with an ordinary double rivetedlap joint, with 3 in. pitch, or an outside patch with a doublerow of rivets along the longitudinal edges, in order to attemptto maintain the steain pressure at 175 lb., we would have to ap-ply an inside cover plate and add an outer row of rivets with6 in. pitch. Then the tension along the row with 3 in. pitchwould be lessened by the shearing value of the outside this case we would have = 175X30X6 = December, 1914 RAILWAY AGE GAZETTE, MECHANICAL EDITION 635 lb., as the total stress in the net section between therivets of the outer row; and (/> — d) X « = (6 — .8125) X sq. in., as the net section. Stress divided by net section= 31,500 H- = 12,162 lb. per sq. in., which appears to be First Course.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroa, bookyear1913
