Minutes Of Proceedings Of The Institution Of Civil Engineers Volumes 21 30 PDF Download

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1870 edition. Excerpt: ...which would be shown if the first line drawn was made any thicker. Although these ex riments were crudely conducted, they a peared to be corroborate by others more carefully made; and e thought, in most operations, they might be relied on as indications whether there was permanent set or not. He had subsequently experimented with more delicate instruments; and in all cases the instrument was attached to the bar direct, and there were no intermediate parts to disturb the results. He found that up to a strain of 8 tons or 9 tons to the inch in ordinary wrought iron, and in the better qualities, up to a strain of 10 tons or 11 tons, there certainly was no permanent set. With steel.there was no permanent set under a strain of from 10 tons to 20 tons, according to the quality. In considering the size of the pin in pro rtion to the bar in tension-bars, he thought consideration should paid to the strains to which the metal was to be subjected. The metal would be extended in the greater portion of the bar, and be compressed at the back of the pin-hole by the in. The conclusion had been pretty well arrived at, that wrong t iron was extended and compressed in equal quantities by an equal amount of ressure on equal areas; therefore, if a tension of 10 tons to the inch was put on the body of the bar. not more compression than 10 tons to the inch should be imposed on the pin; because, if the iron in the body of the bar had acquired a permanent set under a strain of 10 tons r inch, the metal at the back of the pin would have a strain of 0 tons to the inch upon it, if the pin was of the same diameter as the width of the bar; but if the pin was less than the body of the bar, it would have a greater pressure upon it in an inverse ratio; consequently, the...