光学电流传感器系统方案和工作原理

根据光学电流传感器系统中传感头结构及传感机理对其进行分类,详细介绍了全光纤型、块状玻璃型、混合型光纤电流传感器及光纤光栅型电流传感器的传感原理及研究现状,并对它们的优缺点进行比较分析.最后对光学电流传感器的未来研究前景进行展望.     

A relocatable resonant FBG-acoustic emission sensor with strain-insensitive structure

A novel resonant fiber Bragg grating （FBG） based acoustic emission （AE） sensor with relocatable, strain-insensitive and enhanced sensitivity structure is demonstrated for structure health monitoring （SHM） in this paper. With one end of the sensing FBG bonded to a polyimide （PI） plate acoustically the other end free, the sensor can be easily redeployed around coupled with the investigated structure via couplant and the monitored structure surface and get rid of the interference from the strain applied on the monitored structure. Experiment has been conducted to verify the characteristics of this FBG-AE sensor, whose results show that the sensor is insensitive to mechanical strain applied on the monitored structure. It is also shown experimentally that the sensitivity is enhanced by about 1.2 times than the conventiotlal design, while the novel sensor possesses good resonant frequency response to the standard AE waves.     

基坑钢支撑斜牛腿极限承载能力研究

在基坑中，钢支撑的极限承载能力与斜牛腿的受力密切相关。特别是在伺服系统中，由于与斜牛腿相连的伺服系统端部圆板直径较小，极易产生应力集中而导致斜牛腿钢板屈服破坏。通过精细化的数值模拟计算方法，研究钢支撑系统特殊节点构造中斜牛腿的极限承载能力并进行相应的结构优化设计。结果表明：由于伺服系统端部圆盘直径较小，原结构承载板中部容易发生凹陷，通过缩小承载板间距可使荷载能均匀作用在加劲板板上，从而提高斜牛腿的承载能力；增加承载板板厚至25 mm、加宽肋板以及增大伺服系统端部圆板的尺寸，均能有效提高斜牛腿的承载能力。