. American engineer and railroad journal . RESISTANCE OF METALS TO SHEAR. By H. V. Loss, (Continued from page 144.) b. Point of Maximum Besistance. As previously mentioned, an is often being madethat this point exists at a penetration where t = thickness of bar. After measuring up the cardsfor steel bars and flat knives, we find that rupture occursat f^ thickness, varying of course a little on either side of thisfigure. In the same manner we find with 4° knife the pene-tration to be i thickness. For 8° no average relation can begiven, as the variation is very considerable, bein
. American engineer and railroad journal . RESISTANCE OF METALS TO SHEAR. By H. V. Loss, (Continued from page 144.) b. Point of Maximum Besistance. As previously mentioned, an is often being madethat this point exists at a penetration where t = thickness of bar. After measuring up the cardsfor steel bars and flat knives, we find that rupture occursat f^ thickness, varying of course a little on either side of thisfigure. In the same manner we find with 4° knife the pene-tration to be i thickness. For 8° no average relation can begiven, as the variation is very considerable, being | thicknessfor I in. bars and f thickness for SJ in. bars, an increase of100 per cent. The examined results seem to justify an entire disregard forthe width of the bar, the penetration apparently dependingmainly on its tliickuess. The following table gives the averageresults for steel bars with different thicknesses and bevels. TABLE NO. As a general result we may determine the point of maximumresistance for soft steel bars from the following formulas ; d^ = AC\/i^ for 8 top knife(h = 35 t 4° f/i = .3 t 0 or HalFor iron we find with 8 bevel d, ^ i t to i t,with a variation in thickness from 1 in. to 3 on iron were less numerous than on steel. (I) The experi-and the rela- So far none of the derived results have coincided with (ii =J t.* Wliether this expression is true with recard to flat kniveson iron—^the only possible case that still remains—was notdetermined. c. Paint of Final Rupture. When the maximum resistance has been reached the firstdetailed rupture occurs. With a flat knife this first distortionis shown on the broken cross section by the well-known fea-tures of detailed shear, which characteristics especially arefamiliar with punching—namely, as an apparent overlappingof material, as if the punch, which, of course, is nothing moreor less than a flat shear, had dragged parts of the metal withi
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectrailroadengineering
