A New Comparison Index of Estimation Accuracy for Wave Load-Based DBM Superposition Method on Marine Structures

Abstract

The hull stress monitoring (HSM) system, which is the early form of sensor-based structure health monitoring (SHM) in the marine industry, has the limitation that it can only monitor the response at the location where the sensor, long-based strain gauge (LBSG), is attached. To overcome this limitation, the wave load-based distortion basis mode (DBM) superposition method was proposed. This method requires numerous case studies to find the optimal LBSG configuration with best estimation accuracy. To facilitate those studies, efficient way of comparison on the estimation accuracy between cases is necessary. In this study, a new index that can consider both the amplitude and phase shift of the response is introduced. With this index, study with over 150,000 cases are performed for a semi-submersible structure, and the estimation accuracy is compared according to the total number of LBSGs.