(A) new approach to structural availability quantification: its application to slender beam structures considering yield and buckling strength

Abstract

This research introduces the concept of structural availability, which is intrinsically identical to the concept of operational availability in system reliability engineering. Structural availability has the potential to deal with the features of operation and the maintenance of structures, as well as structural integrity, in a quantitative manner, and application of the availability in structural design, as a new design measure, contributes to implementing risk-based design since it can quantitatively indicate overall structural performance in consideration of maintenance policies as well as inherent failure characteristics. In other words, with the structural availability, we can achieve a further optimized and cost-effective design in a practical manner. The new method of structural availability, which is proposed for the yielding and buckling failure of structures, is based on the probabilistic models of structural failure and repair. Stochastic failure model of structures is essential to the structural availability quantification and formulated with structural reliability (or probability of failure), Bernoulli trial assumption, and Poisson approximation. To understand the feasibility of structural availability method, this thesis demonstrates two exemplary slender beam cases that are a longitudinal stiffener of a ship and a simple beam. The calculation results of the example cases illustrate not only the process of quantifying the yielding and buckling availabilities of structures but also the cost-effectiveness assessment on several design options using the structural availability. This thesis is expected to help further understand the feasibility of structural availability application in the actual design process and the risk-based design of structures.