Research On Ultra Large Ship Structure Stress Monitoring System Based On Sensor Technology

Springing,slamming and unreasonable artificial operations,which can cause damage to hull structure of the ultra large ship.It is very difficult to predict these random damage by experience and theory during design and construction stage.It is an effective way to solve this problem by establishing structural stress monitoring system to carry out real-time on-line monitoring of the structural stress of the ultra large ship.Based on the ship structure stress monitoring and assessment system(SMAS)of Harbin Engineering University,some function modules of the ultra large ship structure stress monitoring system(ULSSMS)are redesigned.The selection methods of structure stress monitoring points,the application of fiber optic sensoring technology in the ULSSMS and the system performance evaluation method have been studied in this paper.The main contents are as follows: 1.According to the characteristics of structural stress response of the ultra large ship,integrated with CCS Rules,the structural stress signal acquisition module,the initial stress calculation module,digital filter module and the yield strength assessment module are redesigned.2.The selection methods of monitoring points of the ULSSMS are studied.The longitudinal strength monitoring points are obtained by CCS rules.Through the assessment of structural yielding strength,the yield strength monitoring points based on high stress are obtained.And the fatigue strength monitoring points are obtained by fatigue damage calculation.3.The application of fiber optic sensoring technology in the ULSSMS has been studied.The applicability of optical fiber and optical fiber grating sensor in the ULSSMS is discussed.According to the standard of ship strength sensor performance test,an experiment is designed to select the most suitable fiber bragg grating sensor for the ULSSMS.4.The performance evaluation method of the ULSSMS is studied.The modified Delphi weight method and the ABC classification are used to obtain the primary and secondary relationship of the factors that affecting the speed of data processing.Then,the calculation method of the performance demand of the ULSSMS is established based on the defined data transmission frame structure.