光纤光栅振动加速度传感器的优化设计及振动体的振动模态分析

发布时间：2018-04-15 16:11

本文选题：双等强度悬臂梁 + 有限元分析　；参考：《西安石油大学》2013年硕士论文

【摘要】：进入21世纪，随着科学技术的不断进步，我国交通事业也随之得到了蓬勃发展，在全国范围内，许多公路、高铁桥梁等大结构建筑正在进行修建，但对于该类大型结构建筑物的安全监测仍然为一个空缺，导致了一些大型桥梁结构自身损伤不能被及时发现，从而使自身损伤不断地积累，最终引发建筑物坍塌事故，此类事故发生常常会造成重大的人员伤亡和巨大的经济损失。为避免此类事故的发生，及时、准确的检测到建筑物的损伤情况显得尤为重要。因此，本文主要就光纤光栅加速度振动传感器设计进行了研究和实验，以使其可以满足对建筑物的检测；同时，对基于固有频率的损伤识别技术进行了研究，提出了一套简单、准确的检测方法。实验研制了一种基于双等强度悬臂梁式光纤布拉格光栅振动传感器，首先通过ANSYS软件对传感器进行了数值计算与仿真，得到了在各个阻尼比下传感器的幅频特性曲线和相频特性曲线，不断变化传感器结构参数，寻找最优谐振频率与加速度灵敏度，从而得到传感器最优结构参数；根据仿真所得的最优结构参数进行传感器加工；利用所加工的振动传感器进行振动台试验研究并对所得实验数据进行处理，将处理后的数据与ANSYS软件仿真所得到的数据进行比较，可知，振动平台所测得的实验结果与ANSYS软件仿真结果相吻合：传感器的谐振频率为80.74Hz，可实现50Hz以下低频振动信号的实时监测，在5-50Hz之间的加速度灵敏度约为20.85pm/m·s-2。该传感器可以很好地获得建筑物的振动信息，从而为损伤识别提供准确、可靠的振动信号。对损伤识别的一般方法进行简单介绍，，明确了监测物健康状况与固有频率之间存在一定关系。对结构尺寸、材料完全相同的4组桥梁模型进行人为制造损伤，其中4组损伤程度各不相同，对4组桥梁模型进行相同的实验，实验得出监测物损伤程度与固有频率之间的关系，当损伤程度增加时，固有频率将不断减小；通过ANSYS软件对实验中的4组桥梁建立仿真模型，进行模态分析，得出不同损伤程度下桥梁的固有频率，从而得到损伤程度的增加导致固有频率的减小，所得结论与实验相吻合。因此，当桥梁受到损伤时，其固有频率减小。
[Abstract]:In the 21st century, with the continuous progress of science and technology, the transportation industry in China has also been booming. In the whole country, many large structural buildings, such as highways, high-speed rail bridges and so on, are being built.However, the safety monitoring of this kind of large structure buildings is still a vacancy, which leads to the damage of some large bridge structures can not be found in time, which makes the self-damage accumulate continuously, and finally causes the building collapse accident.Such accidents often result in heavy casualties and huge economic losses.In order to avoid such accidents, timely and accurate detection of building damage is particularly important.Therefore, in this paper, the design of fiber Bragg grating acceleration vibration sensor is studied and experimented, so that it can satisfy the detection of buildings. At the same time, the damage identification technology based on natural frequency is studied, and a set of simple method is put forward.Accurate detection method.A kind of fiber Bragg grating vibration sensor based on double strength cantilever beam is developed experimentally. Firstly, the sensor is numerically calculated and simulated by ANSYS software.The amplitude-frequency characteristic curve and phase frequency characteristic curve of the sensor under each damping ratio are obtained, and the structural parameters of the sensor are constantly changed, and the optimum resonance frequency and acceleration sensitivity are found, and the optimal structural parameters of the sensor are obtained.According to the optimum structural parameters obtained by simulation, the sensor is machined, and the vibration table test is carried out by using the vibration sensor, and the experimental data are processed.Comparing the processed data with the data obtained by ANSYS software simulation, we can see,The experimental results obtained from the vibration platform are in agreement with the simulation results of ANSYS software. The resonant frequency of the sensor is 80.74 Hz, which can realize the real-time monitoring of the low frequency vibration signal below 50Hz, and the acceleration sensitivity between 5-50Hz is about 20.85pm/m s-2.The sensor can obtain the vibration information of buildings and provide accurate and reliable vibration signals for damage identification.The general methods of damage identification are briefly introduced, and the relationship between the health status of the monitor and the natural frequency is clarified.Four groups of bridge models with the same structure size and material were subjected to artificial damage, and the four groups of bridge models were subjected to the same experiments.The relationship between the damage degree and the natural frequency of the monitored object is obtained. When the damage degree increases, the natural frequency will decrease continuously. The simulation model of the four groups of bridges in the experiment is established by ANSYS software, and the modal analysis is carried out.The natural frequency of the bridge with different damage degree is obtained, and the increase of the damage degree leads to the decrease of the natural frequency, and the conclusion is in agreement with the experiment.Therefore, when the bridge is damaged, its natural frequency decreases.
【学位授予单位】：西安石油大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU317;TP212

【参考文献】