Study On The Strength Of Primary Members With Web Openings

Due to the arrangements of pipelines, cables and other members, there are always web openings on primary members in ship structures, which usually have negative effects on the strength characteristics of primary members. The strength characteristics of primary with web openings are lack of systematic investigation, and the designs of web openings are on the basis of rules by classification societies. It is often unable to conduct strength analysis using direct calculation method to design openings whose parameters exceeding the rules when the loads on primary members are uncertain.A comparing strength design method is proposed to research the web openings exceeding the rule requirements on primary members with uncertain loads. The strength characters of web openings with parameters both fulfilling and exceeding the rules are analyzed using finite element method. Finally, some optimization advices are proposed for reinforcements.The main research work and contents of this paper are as follows:(1) Summarize the mechanical characteristic of primary members, and discuss the influences of web openings on strength characteristics. Then compare the requirements on web openings by different classification societies.(2) The stress distribution and local deformation near the web opening is analyzed combined with Vierendeel theory, and the results show that larger secondary moments are formed by shearing forces when web openings are located near the end, which cause negative effects on strength characteristics.(3) The strength characteristics of primary members with web openings exceeding the rules are calculated before and after reinforcing. The ring + plate method is shown to be effective for certain opening parameters.(4) Optimize ring + plate reinforcement method. The breadth of ring should be effective breadth (6 times web thickness), and the thickness of ring should equal the web thickness. The plate thickness could equal the web thickness, and could be thickened according to the practical needs. The research results of this paper can be helpful for increasing the knowledge of the strength characteristics of primary members with web openings, and improving design of openings and reinforcements.