동적특성을 이용한 부유식 구조물의 손상탐지

Abstract

The importance of utilization of ocean space increases due to high population and narrow land space. The development of a new technology for future use of ocean space, such as integrity estimation method of floating structures, is needed. Nowadays, people’s desire for the waterfront space is increasing, and more people want to spend their leisure time close to the water.

Because the floating structures are exposed to severe conditions, damage might be accumulated in the structural members, and damage location and severity must be immediately assessed by monitoring the responses of structures. If the structural damages are not found in early stage, it could endanger a large population or cause substantial economic loss. Therefore, the integrity estimation is essential, and it is critical concern to users, managers, and constructors.

This thesis proposes a damage evaluation technique using mode shapes to detect and locate damage in the lower part of floating structure.

A damage index, utilized to identify possible location of damage, is expressed in terms of modal displacements that can be obtained from mode shapes of the undamaged and the damaged structures. The possible damage locations in the structure are determined by the application of damage indicators according to previously developed decision rules. The accuracy and feasibility of the proposed method is demonstrated using numerical and experimental data.