An Iterative Method for Structural Health Monitoring in a Jacket Type Offshore Platform Based on Mode Reduction

Abstract

 Abstract—Structural safety assessment is one of the most important items in extraction of energy resources by using offshore structures. Despite uncertainty in determining the most important parameters for the structure final design, it is usually complicated. Thereupon, damage detection techniques have received significant attention in order to assess the safety and reliability of offshore structures during their service life. This research represents the cross-model cross mode (CMCM) method in combination with the two-stage proprietary reduction (TPR) technique that is capable of detecting the damage to individual members by using results of the experiment on physical model of the offshore jacket platforms, when limited, spatially incomplete modal data is available. We evaluated selection procedure inactive degrees of freedom in process of the model reduction with a reasonable criterion by using the sensitivity analysis of system response under base excitation. Meanwhile, the finite element model updating based on the empirical model utilized to overcome the uncertainty in modeling. This performance indicates that the convergence rate and the compu-ting time of the proposed method are significantly superior to those of the prior iterative method with or without noise.