基于光纤光栅的高温法兰螺栓紧固力测量技术研究

发布时间：2018-02-24 17:19

  本文关键词： 高温法兰 螺栓力测量 金属封装RFBG　出处：《华东理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：合适的螺栓预紧力对保证高温法兰接头的安全性能是非常重要的。众所周知,高温工况下由于法兰接头各部件热胖胀系数不同、垫片应力下降以及材料的高温蠕变等会导致螺栓力发生明显的变化,螺栓预紧力变化经常会引起法兰接头的泄漏。由于高温条件下影响法兰密封性能的因素很多,很难通过传统的设计来保证法兰接头的安全。因此为了更有效的判断实际运行中高温法兰接头的安全性能,准确测量高温法兰螺栓预紧力变化非常有必要。本文研究并制备出耐高温金属封装可再生光纤布拉格光栅(metal-packaged regenerated fiber Bragg grating,MPRFBG)传感器。基于该耐高温应变测量传感器,提出高温法兰螺栓力测量方法。本文主要研究内容及结论如下:(1)通过磁控溅射和电镀工艺制备出针对高温法兰螺栓力测量的一种新型耐高温MPRFBG传感器。光纤表面和Ti层之间以及Ni层和金属基体之间具有较好的界面结合强度。采用点焊的方式将MPRFBG传感器固定于螺栓光杆的表面,可实现高温法兰连接螺栓力的测量,为了方便起见,本文中将这种点焊安装有MPRFBG传感器的螺栓称为"MPRFBG-螺栓"。该传感器金属封装基体的结构形式可以最大程度地减少传感器安装对被测螺栓本身性能的影响。(2)基于FBG传感器的测量原理,提出一种便于工程应用的高温法兰螺栓力测量方法,该方法可以克服MPRFBG传感器对温度和应变交叉敏感的问题。通过500℃以内不同温度下的单轴拉伸试验和热响应试验获得MPRFBG-螺栓对螺栓轴向力和温度的响应特性。MPRFBG-螺栓在室温到500℃温度范围内的恒温条件下,Bragg波长对螺栓轴向力表现出良好的线性、稳定性和重复性。MPRFBG-螺栓在500℃以下的温度范围内表现出良好的温度传感特性,采用三次多项式函数可以准确拟合Bragg波长与温度之间的关系。(3)设计一个简单的高温紧固件螺栓力测量装置,并在400℃以下进行了试验,试验结果表明MPRFBG-螺栓可以被用于温度高达400℃条件下的螺栓力测量。对比MPRFBG-螺栓测量结果和有限元模拟结果。结果表明,螺栓力的有限元模拟结果与MPRFBG-螺栓测量结果具有较好的一致性。这项测量技术可为高温工况下螺栓紧固件的结构健康监测提供一种新的可能。
[Abstract]:Proper bolt pretightening force is very important to ensure the safety performance of high temperature flange joints. As we all know, under high temperature conditions, due to the different thermal expansion coefficient of each component of flange joint, The decrease of gasket stress and the creep of material at high temperature will lead to obvious change of bolt force, and the change of bolt preload force will often cause leakage of flange joint. There are many factors that affect the sealing performance of flange under high temperature. It is difficult to ensure the safety of flange joints by traditional design. Therefore, in order to judge more effectively the safety performance of high-temperature flange joints in actual operation, It is necessary to accurately measure the change of pretightening force of high temperature flange bolts. In this paper, the metal-packaged regenerated fiber Bragg gratings MPRFBG sensor for high temperature metal packaging has been studied and fabricated. The main contents and conclusions of this paper are as follows: 1) A new high temperature MPRFBG sensor for bolt force measurement of high temperature flange has been fabricated by magnetron sputtering and electroplating. The MPRFBG sensor is fastened to the surface of the bolt rod by spot welding. Can realize the high temperature flange connection bolt force measurement, for convenience, In this paper, the spot welding bolt with MPRFBG sensor is called "MPRFBG- bolt". The structural form of the metal packaging matrix of the sensor can minimize the effect of sensor installation on the performance of the bolt under test. The measuring principle of the inductor, A high temperature flange bolt force measurement method is presented, which is convenient for engineering application. This method can overcome the problem that MPRFBG sensor is cross-sensitive to temperature and strain. Through uniaxial tensile test and thermal response test at different temperatures within 500 鈩，

本文编号：1531070