基于刀型Terfenol-D的超磁致伸缩传感器的研制及其激励实验研究

发布时间：2018-03-26 18:45

本文选题：超磁致伸缩　切入点：刀型Terfenol-D　出处：《江苏大学》2017年硕士论文

【摘要】：随着全球社会经济的发展,管道运输由于具有运输量大、连续性好、安全系数高、成本低等优点在五大运输方式中担任着不可或缺的角色。然而随着管道使用时间的过长,且由于环境及人为的影响,管道会出现不同程度和不同形式的损伤,包括划痕、破损、腐蚀等。管道的这些损伤会带来极大的能源浪费和经济损失,更为严重的是可能会造成人身伤亡事故,因此,管道检测尤为重要。由于常规的检测大多采用逐点检测的方法,检测速度慢,检测距离较短且效率低,而超声导波检测技术具有传播距离长,衰减小,检测效率高等优势越来越受到重视。在超声导波检测中,目前被用于管道检测最常见的传感器是压电式传感器,其敏感元件采用PZT,由于该材料的机电耦合系数较低,能量转化效率较差限制了检测距离。与PZT材料相比,超磁致伸缩材料Terfenol-D具有较高的机电耦合系数及能量转换效率,因此本文将超磁致伸缩材料Terfenol-D作为传感器的敏感元件,由于检测时需要与管道任意表面耦合,一般的长方体和圆柱状的振动元件无法满足。因此,本文将Terfenol-D设计成一种类似刀型的结构,能实现与管道任意表面耦合。采用理论与实验研究相结合的方式对超磁致伸缩传感器的内部组件进行了设计,并研究了传感器内部组件的主要参数对激励效果的影响,本文主要的研究工作和成果包括:1)为了研究传感器内部组件的各项参数对激励效果的影响,建立了管道检测实验系统,运用传输线法对传感器的内部各项参数进行实验研究,测试超磁致伸缩传感器的激励性能。2)为了使Terfenol-D传感器能适用于管道任意表面检测,采用模拟软件分析了刀型和长方体结构的Terfenol-D在相同信号下的振动情况,由于刀型结构存在其他方向的微小振动,本文配置了一种吸波材料,采用理论计算及实验的方式分析了背衬层的位置及厚度对激励信号的影响。3)对Terfenol-D传感器的激励幅值及信噪比两个方面进行研究,设计了偏置磁场及提供交变磁场的驱动线圈,采用实验的方式分析了线圈的各项参数及永磁铁对激励信号的影响规律。利用研制的刀型Terfenol-D超磁致伸缩传感器与电陶瓷传感器进行激励试验,分别从激励幅值、回波系数及定位精度进行了对比分析,研制的刀型Terfenol-D超磁致伸缩传感器激励性能具有突出的优势。
[Abstract]:With the development of global society and economy, pipeline transportation plays an indispensable role in the five modes of transportation because of its advantages of large volume, good continuity, high safety coefficient and low cost. And because of environmental and man-made effects, pipelines will suffer various degrees and forms of damage, including scratches, breakages, corrosion, etc. These damage to pipelines will cause great energy waste and economic losses. What is more serious is that it may cause personal injury and death accident, so pipeline detection is especially important. Because the conventional detection mostly adopts point-by-point detection method, the detection speed is slow, the detection distance is short and the efficiency is low. However, ultrasonic guided wave detection technology has the advantages of long propagation distance, low attenuation, high detection efficiency and so on. In ultrasonic guided wave detection, the most common sensor used in pipeline detection is piezoelectric sensor. Because of the low electromechanical coupling coefficient and low energy conversion efficiency, the detection distance is limited by the low energy conversion efficiency of the material. Compared with the PZT material, the giant magnetostrictive material Terfenol-D has higher electromechanical coupling coefficient and energy conversion efficiency. Therefore, in this paper, the giant magnetostrictive material (Terfenol-D) is used as the sensitive element of the sensor. Because of the need of coupling with any surface of the pipe, the general cuboid and cylindrical vibration elements cannot be satisfied. In this paper, Terfenol-D is designed as a kind of knife structure, which can be coupled with any surface of the pipe. The internal components of the giant magnetostrictive sensor are designed by combining theoretical and experimental studies. The main work and results of this paper include: (1) in order to study the influence of the parameters of sensor internal components on the excitation effect, a pipeline detection experiment system is established. In order to make the Terfenol-D sensor suitable for any surface detection of pipeline, the internal parameters of the sensor are studied experimentally by using the transmission line method, and the excitation performance of the giant magnetostrictive sensor is tested. The vibration of Terfenol-D with knife shape and cuboid structure under the same signal is analyzed by means of simulation software. Due to the existence of small vibration in other directions of the knife structure, a kind of absorbing material is configured in this paper. The influence of the position and thickness of the backing layer on the excitation signal is analyzed by theoretical calculation and experiment. The excitation amplitude and signal-to-noise ratio of the Terfenol-D sensor are studied. The bias magnetic field and the driving coil providing the alternating magnetic field are designed. The parameters of the coil and the influence of permanent magnet on the excitation signal are analyzed by means of experiments. The excitation tests are carried out by using the knife type Terfenol-D giant magnetostrictive sensor and the electric ceramic sensor, respectively from the excitation amplitude. The echo coefficient and positioning accuracy are compared and analyzed. The developed Terfenol-D giant magnetostrictive sensor has outstanding advantages in excitation performance.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP212

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