Rivets with Large Diameter for Hull Use (First Report)

Abstract

Although there is a great decay in the use of rivets for ship construction since an extensive application of the electric welding, the riveted connection is still being adopted at seam joints in a main hull. With a remarkable increase in the size of vessels at the present time, the plate used for the seam joints might be of about 40 mm in thickness and the rivets required for the plate are of either 32 mm or 36 mm in diameter. However, it has been regarded from viewpoints of both practical technique and bodily powers of riveters as considerably difficult to carry out a thorough operation with such large sized rivets at fields and to expect satisfactory results from the performance. This problem was then taken up as one of the research subjects concerning the construction of mammoth tankers, and an investigation has been conducted jointly by the Nippon Kaiji Kyokai and the Kure Shipbuilding and Engineering Company.There are many investigations reported on the rivets and the riveted joints, most of which deal with the problem on the joint efficiency based upon the breaking strength of both rivets and plates. It is the seam joints, however, that is currently in question, for which the problem on slip at the joints and water-tightness are of primary importance rather than on the breaking strength of the rivets. Even though it has been considered that the slip at the riveted joints is influenced essentially by a clamping force of the rivets and by friction at the contact surface between two plates, it seems that reliable data on the clamping force are not so much available.The author measured the clamping force of rivets of various shapes and sizes by means of wire strain gages affixed to a plate fixure which was simulated as an actual riveted joint. It was also estimated from the observation that the pressure distribution along the contact surface was of similar type as that calculated by a use of the ordinary two-dimesional theory of elasticity.