Proceedings of the Annual Meeting of the Baptist State Convention [Serial] (1882)

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. 1920 edition. Excerpt: ... 0.7854rf(aS) r Examining Eq. 1 and 2, it is evident that as the value of P increases, E increases by 1 and decreases by 2. Therefore, starting with the smallest possible value for P, without considering the interference of the rivet heads, where P would equal d, that is the rivet shanks would touch each other (in which case the efficiency would be zero by 1 and by 2), and increasing the value of P, the efficiencies by these two formulae approach each other and become equal at some higher value for P. Equating 1 and 2, the value of P, in terms of C, T and d, is found where the efficiency by 1 and 2 will be equal, thus: Cd _ d PT P or /n 4 It is evident that a single-riveted joint cannot have a higher efficiency than when P has this value, for a change in the value of P will result in a lower efficiency by either Eq. rjl or 2. It is seen by examining Eq. 3, that the efficiency due to the shearing of the rivets, for any finite value of P, may be anything desired, providing the value of d is not limited. To determine the value of d, if the efficiency by Eq. 3 is to be the same as for Eq. 2, equate these, as follows: . Cd = 0.7854tP(2S) PT PIT or tC d = 0.7854(25) Since the value of d, as given by Eq. 5, is such that the crushing of the plate and the shearing of the rivets are equally possible, any increase in d beyond this value would cause the shearing of the rivets to cease to be a factor. This is so, since the shearing strength increases as the square of d, while the crushing strength increases directly as d. Therefore, to design a single-riveted joint of maximum efficiency, it is only necessary to select rivets of such size that: tC d= 0.7854(25)6 and space them so that: P-d( + l) Since the efficiency of such a joint will...