METHODOLOGY FOR THE DEVELOPMENT OF RELIABILITY-BASED DESIGN CRITERIA FOR SURFACE SHIP STRUCTURES

The development of reliability-based design criteria for surface ship structures needs to consider the following three components: (1) loads, (2) structural strength, and (3) methods of reliability analysis. A suggested methodology that consists of the following two approaches was developed: (1) direct reliability-based design, and (2) load and resistance factor design (LRFD) sheets. According to this methodology, loads can be linearly or nonlinearly treated. Also in assessing structural strength, linear or nonlinear analysis can be used. The reliability assessment and reliability-based design can be performed at several levels of a structural system, such as at the hull-girder, grillage, panel, plate and detail levels. A rational treatment of uncertainty is suggested by considering all its types. Also, failure definitions can have significant effects on the assessed reliability or resulting reliability-based designs. A method for defining and classifying failures at the system level is suggested in this paper. The method considers the continuous nature of redundancy in ship structures. After evaluating commercially available computer software, an outline of a computer program is provided for the purpose of future implementation of the two approaches. Also, a bibliography is provided at the end of this paper for the same purpose.