用于板结构损伤检测的磁致伸缩传感器

基于铁磁性材料的磁致伸缩特性,提出一种用于非铁磁性板结构损伤检测的磁致伸缩传感器。该传感器分为激励和接收两部分,由8字型线圈、镍带以及偏置永磁铁组成。根据磁致伸缩效应,激励部分在板中激励导波,波在板中传播,遇缺陷及边缘反射,通过磁致伸缩逆效应,由接收部分接收其反射信号。根据反射信号的到达时间和波在板中传播的速度,可判断出板中缺陷所在位置。改变恒定偏置磁场与时变磁场的方向可以在板中激励不同波型的导波。实验结果证明:该传感器设计是可行的,且具有价格便宜、灵敏度高、可与被测结构分离等优点。

Magnetostrictive sensor for damage detection in plate

Based on the magnetostriction of ferromagnetic material, a kind of magnetostrictive sensor for damage detection in a nonferromagnetic plate is proposed. The sensor is composed of a transmitter and a receiver, which both consist of a figure-of-eight coil, a nickel strip and a couple of bias permanent magnets. The transmitter generates guided wave in the plate according to magnetostrictive effect, and then it propagates in the plate and is reflected by the damages and edges of the plate. Then based on the inverse magnetostrictive effect, the receiver catches the wave signal. According to the reach time of the reflected wave signal and the velocity of the generated wave, the location of the damage in the plate can be identified. Changing the direction of constant bias magnetic field can transmit different wave mode in the plate. Experiment results show that the magnetostrictive sensor is feasible, and it is cost-effective and non-contact.