Reinforcement of Openings in Structure of Surface Ships, Other Than in Protective Plating

摘要

These design data were prepared for guidance in designing reinforcement around openings in structural members of naval vessels. Such openings are made: (a) To lighten members. (b) For access or inspection. (c) To allow passage of wiring, piping, and ventilation ducts. Every opening in a stressed area of a structural member causes stress concentrations. If opening is large in proportion to width of member, or too near an edge, stress concentration is increased. If size or location of opening is such as to unduly impair the strength of an important member, measures should be taken to reduce the stress in way of the hole. This may be done: (d) By changing location of opening. For example, in a beam, locate holes near neutral axis. (e) By changing shape of opening. (f) By fitting an insert plate around opening. (g) By fitting a reinforcing ring around opening. The purpose of such reinforcement is to concentrate extra material around opening, close enough to plane of plate so that it will deform with loaded plate, thus absorbing energy and reducing strains around opening. The rules below deal with this type of reinforcement.