A Treatise on Non-Metallic Materials of Engineering Volume 3 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1900 Excerpt: ... of impact on the tough metals having no definite limit of elasticity is modified by the velocity of the striking mass, and by the inertia of the piece attacked, to an extent, as yet, not fully determined. The experiments of Kick indicate a considerable increase of total work of resistance, when the piece is deformed in this manner, over that noted when the compression is produced slowly by steady pressure. The experiments of the Author also indicate that this work is the greater, with soft and malleable metals, as the velocity of action is increased. The real efficiency of the press, as above, is thus probably somewhat greater than the figures obtained would indicate. In the preceding figure, the areas cut off under the curves by the ordinates in full lines are measures of the work of the most efficient drop-hammers, while those cut off by the dotted ordinates give the work of less efficient machines. 173. Copper, Subjected to Transverse Stress, is probably always to be considered as belonging to the second class of materials treated of in Art. 161, and as more correctly represented by the equation b (p. 260) of Art. 166, than the usually adopted equations preceding them, i.e. M' = Rl ' f% dy dx, and Fl = 2 it s, P idr, it io Jr, instead of M=-i PV dy dx, and Fl = 2--f' r- dr, the former of which, for rectangular bearers and solid shafts, would become, were T = C, M' =-R; Fl= 2.2 stf, 4 instead of The values of T and C are not, however, the same, and the differential expression must be integrated for the two sides of the bar separately. Cast copper, tested by transverse stress, when of fair quality should give figures equal to, or exceeding, those obtained in the record which follows: TABLE XLII. The modulus of rupture for good cast copper should thus...