Fundamental Study on Development of Smart Marine Structures

为了提高海洋设备和结构在恶劣环境条件下的结构可靠性，在结构材料中融入自诊断、自修复等智能功能，对实现智能海洋结构进行了基础性研究。1)研究了损伤检测传感器的结构和方法。对埋入树脂中的单根光纤进行了拉伸试验，并对玻璃钢试件进行了拉伸和弯曲试验，结果表明，用OTDR(光时域反射仪)可以检测到夹层光纤的损伤，证实了光纤作为一种分布式临界应变检测器的适用性。基于激光多普勒效应和拉伸试件在循环载荷作用下的变形，研制了光纤速度传感器，并与应变片进行了对比，测量了悬臂梁试件的振动。…的适用性探讨了光纤应变传感器在海洋结构中的应用。2)研究了应用压电致动器对柔性结构进行振动主动控制的可能性。制作并测试了一种悬臂梁试件，其中Bimorf压电元件作为弯曲变形的致动器，激光弯沉仪和应变计作为传感器。3)将压电聚合物薄膜(聚偏氟乙烯：PVDF)和研制的光纤激光多普勒测振仪(LDV)应用于柔性复合梁的振动控制。理论分析表明，控制系统始终是稳定的。在实验研究中，开发了一种模拟控制电路，并将其应用于多模振动的速度反馈控制。通过仿真和实验对控制系统的有效性进行了评估。较少

A fundamental study was performed aiming at the realization of a smart marine strucure, in which smart functions such as self-diagnosis or self-repairing are incorporated in structural material itself, in view of enhancing the structural reliability of ocean equipments and structures under severe environmantal conditions.1) The methodology and the construction of sensors for damage detection were examined. Tensile test od singl optical fiber embedded in a resin, tensile and flexure tests of GFRP specimans were carried out, and it was shown that the damage of mebedded optical fibers were detected by OTDR (Optical Time Domain Reflectometer) and the applicability of optical fiber was confirmed as a distributed detector of critical strain. Fiber-optic velocity sensor was developed based on Laser-Doppler effect and deformation of tensile specimen under cyclic load, vibration of cantilever beam specimen were measured with the developed sensor in comparison with strain gages. The applicabilit … More y of fiber-optic strain sensors to marine structures was also discussed.2) The possibility of active vibration control of flexible structure by applying piezoelectric actuators was examined. A cantiever beam specimen was manufactured and tested, in which a Bimorf piezoelectric element was incorporated as an actuator inducing flexural deformation as well as laser deflectometer and strain gages as sensors. A system identification of this active/adaptive atructure was carried out and thr active vibration control performance was evaluated.3) Piezoelectric polymer films (polyvinylidene fluoride : PVDF) and the developed fiber-optic Laser Doppler Vibrometer (LDV) were applied to the vibration control of a flexible composite beam. Theoretical consideration confimed that the control system is always stable. In the experimental study, an analog control circuit was developed and applied to velocity feedback control of multi-modes vibration. The effectiveness of the control system was evaluated by simulation and experiments. Less