基于FBG分布传感的机械结构裂纹损伤识别方法研究

发布时间：2018-03-07 19:06

本文选题：应变频响函数参数　切入点：数值分析　出处：《武汉理工大学》2012年硕士论文　论文类型：学位论文

【摘要】：现代化生产的高速高效发展使得机械设备不得不面临日益复杂的工作条件和越来越长的工作时间,如此机械设备结构会不可避免的受到损伤,而且由各种小损伤导致的重大灾难性事故更是屡见不鲜。对于结构中的微小损伤的识别,必须应用对损伤具有更敏感识别能力的应变型指标。基于振动的损伤识别是目前实际工程应用最为广泛的方法,而基于应变类频响函数参数的损伤识别指标也得到越来越多的关注。应变损伤识别参数的准确性,依赖于应变传感器对损伤结构应变场的准确测量,用传统的电气类传感器作分布式测量繁琐而低效,光纤光栅应变传感器体小、质轻、抗电磁干扰,更具有可波分复用的优势,是结构应变场测量不可多得的一种传感器。本文以工程应用中十分常见的四角点固定支撑的45#薄钢板作为研究对象,并以应变类频响函数作为振动损伤识别指标的基础,利用其相关参数对薄板结构上的裂纹损伤进行识别。对此本文详细分析了该薄板结构的横向振动特性,进行了数值分析计算和大量的实验研究并对实验所测得的信号进行了处理分析。基于损伤识别指标应变频响函数灵敏度参数βsfrf和应变功率谱密度频响函数灵敏度参数βpsd,本文利用ANSYS有限元分析软件对四角点固定支撑薄板结构实现了不同位置裂纹损伤识别的模拟仿真分析；并在此基础上搭建了基于FBG分布传感的实验测试系统,通过对实验所得的结构应变矩阵的分析,成功提取了应变类频响函数,分别给出了应变频响函数灵敏度参数βsfrf和应变功率谱密度频响函数灵敏度参数βpsd两种损伤识别指标矩阵的三维柱状图,得出应变功率谱密度频响函数灵敏度参数βpsd在实际应用中能够更好的对薄板结构中的裂纹损伤进行识别。
[Abstract]:With the rapid and efficient development of modern production, machinery and equipment have to face increasingly complex working conditions and longer and longer working hours, so the structure of machinery and equipment will inevitably be damaged. And major catastrophic accidents caused by various minor injuries are common. For the identification of minor damage in structures, It is necessary to apply the strain type index which is more sensitive to damage identification. Vibration based damage identification is the most widely used method in practical engineering at present. More and more attention has been paid to the damage identification index based on strain frequency response function parameters. The accuracy of strain damage identification parameters depends on the accurate measurement of strain field of damaged structure by strain sensor. Traditional electrical sensors are used for distributed measurement, which are complicated and inefficient. Fiber Bragg grating strain sensors are small, light, anti-electromagnetic interference, and have the advantage of wavelength division multiplexing. It is a rare sensor for structural strain field measurement. In this paper, 4thin steel plate with four corners fixed support is used as the research object, and the frequency response function of strain class is used as the foundation of vibration damage identification index. The crack damage of thin plate structure is identified by the relevant parameters. In this paper, the transverse vibration characteristics of the thin plate structure are analyzed in detail. Numerical analysis and a large number of experimental studies have been carried out, and the signal measured in the experiment has been processed and analyzed. Sensitivity parameter 尾 sfrf of strain frequency response function based on damage identification index and sensitivity of frequency response function of strain power spectral density. In this paper, ANSYS finite element analysis software is used to simulate and analyze the crack damage identification of four-corner fixed-supported thin plate structure at different positions. On this basis, an experimental testing system based on FBG distributed sensing is built. By analyzing the structural strain matrix obtained from the experiment, the frequency response function of strain class is extracted successfully. The three dimensional histogram of strain frequency response function sensitivity parameter 尾 sfrf and strain power spectral density frequency response function sensitivity parameter 尾 psd are given. It is concluded that the strain power spectrum density frequency response function sensitivity parameter 尾 psd can better identify the crack damage in thin plate structure in practical application.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH165.3

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