. American engineer and railroad journal . {5ttff/.7f a^-l —•■•■; , ■ i i i maximum deflection at the center can be shown to beRHL DJL r EI — K!.-- or 7TE1- DL? I fence at a maximum the arm of R, or I) as the case maj be, be-comes RHL=H + or I -f- tEI — RLS J ^ tt=EI —DL2 DJ1/ and the bending moment is sVeotrjjf Ax/s< tPi/Z/iffy - Oyerttpttf fosufrar?/£/?d S/toc&\ D/atfra^s /0 <&. Sin?i/ar /o 8 v/lf/t Momet?/ Q/aqnam Be/ob Neofra//fms li ! 7 ! ! i More, 12. Com/ttt/a/iott of 7 &£ H + RHL tEI —RL1 ][■ DJL* ] R I I J + To draw the curve represented by ttie transcendental equationwoul
. American engineer and railroad journal . {5ttff/.7f a^-l —•■•■; , ■ i i i maximum deflection at the center can be shown to beRHL DJL r EI — K!.-- or 7TE1- DL? I fence at a maximum the arm of R, or I) as the case maj be, be-comes RHL=H + or I -f- tEI — RLS J ^ tt=EI —DL2 DJ1/ and the bending moment is sVeotrjjf Ax/s< tPi/Z/iffy - Oyerttpttf fosufrar?/£/?d S/toc&\ D/atfra^s /0 <&. Sin?i/ar /o 8 v/lf/t Momet?/ Q/aqnam Be/ob Neofra//fms li ! 7 ! ! i More, 12. Com/ttt/a/iott of 7 &£ H + RHL tEI —RL1 ][■ DJL* ] R I I J + To draw the curve represented by ttie transcendental equationwould mean laborious calculation and plotting. It will be foundto be a very close approximation to assume that this maximumbending moment was produced by a uniformly distributed loadover the total length of the beam. This will readily give a curvewhich can be combined with the other moment curves represent- PULLING 5HOCK5 16-Combinaftbt? of \7 & /C 14. Comlma/ioi? of 7 St f IS. Coml/trat/or? of7&//.. ^]JJlj|jj E= coeff. of elasticity. I = moment of inertia. In this there has been neglected^2, which is an infinitesimalin beams properly designed for stiffness. This value is but Soper cent, of what it would be for the theoretical curve with a loadconcentric with neutral axis. This again does not take into ae- ing the conditions obtaining from static lading. Bending mo-ment curves 8 and 9 are thus drawn. The above procedure is best adapted to the careful investiga-tion of a finished design more than to the preliminary choosingof trial underframe sections. For the latter a ready approxi-mation can be made by considering the end bending momentsimply as Rh or DJ and securing the uniform load winch willgive this corresponding moment at the center of the beam. Th isu L-1 8RH 1 I tj RH or DJ = and w = or 8 L2 L2 14 AMERICAN ENGINEER AND RAILROAD JOURNAL. which are equated moments taken about the point of intersec-tion cf the vertical center line between trucks and the
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectrailroadengineering
