Composite intake and exhaust louvers for marine applications

摘要

Commercial, naval ships, as well as other marine transport vessels use heavy, multi-blade steel weather louvers to cover their intake and exhaust openings to the outside. Costly time, labor and materials are constantly expended to protect and maintain these steel louvers from the corrosive effects of the sea environment. Louvers made from fiber-reinforced plastic composite materials such as fiberglass are low in weight and can eliminate corrosion and deterioration caused by salt-laden moisture and ship-stack exhaust gases. The use of weather tight non-metallic composite louvers will also eliminate galvanic corrosion problems due to inadequate louver-to-bulkhead attachment practices. Such low maintenance louvers will provide reliable operation and will eliminate the current shipboard maintenance burden. This paper will discuss in detail a composite louver design that is simple and reliable and can be fabricated by an inexpensive composite pultrusion process which is integrated with an inexpensive numerically controlled (NC) finishing operation. The paper presents the details of this composite pultrusion process, including the composite design architecture. A finite element model (FEM) and stress analysis is also presented. The composite louver concept discussed in this paper has robust, yet lightweight composite structural characteristics. It is attractive from the ship designer's point of view since it will provide a greater level of design flexibility at a minimum cost. The proposed composite louver design can be easily adapted to satisfy economically any gamut of ship-set sizes for any ship compared to metallic louvers or other composite louvers that may be in current ship use. The authors of this paper have successfully demonstrated the environmental and structural feasibility as well as the economical practicality of the proposed composite louver for use on U.S. Navy ships.