An improved model reduction-modal based method for model updating and health monitoring of an offshore jacket-type platform

Abstract

Numerous constructed jacket platforms in the Persian Gulf require continuous monitoring due to aging which poses a significant hazard to the environment. The main aim of this study is to sketch a health monitoring system to address the problem of limitations and shortcomings of sensor networks and also to solve the localization problem. In order to achieve this goal, experimental modal analysis (EMA) is performed on a physical model of an offshore jacket platform to develop a numerically updated finite element model. Both traditional and improved Cross-Model Cross-Mode (CMCM) iteration algorithms are employed for this purpose and different model order reduction methods are compared in terms of their effects on the structural dynamic behavior of the case-study (SPD8 jacket platform). A new formulation is also proposed for the first time to compare the results of damage scenarios using both iteration algorithms. The effectiveness of the methodology in practical cases is also assessed by considering various numbers of sensors. According to the results, the improved iteration technique eliminates the detrimental impacts of the model reduction procedure on the proposed methodology, and physical parameters such as length, type, and location of a member play significant roles in the success of a damage detection scenario.