摘要
对利用磁致伸缩效应在钢绞线中激励接收纵向导波模态的方法进行理论分析和试验研究。分析在公称直径为17.80mm的7芯钢绞线中纵向模态的传播特性。选取钢绞线外围钢丝中频率160kHz的L(0,1)模态用于钢绞线的健康检测。基于该模态的传播特性和钢绞线缠绕式外表面的特点,研制一种专用磁致伸缩传感器,用于7芯钢绞线的超声导波检测。该传感器的主要结构包括轴对称三磁路励磁结构和正反正绕向的三段式螺线管。三磁路励磁结构用来产生强度适合且均匀的偏置磁场,并设计专用夹片以降低钢绞线不规则外形所造成的空气磁阻。螺线管每段绕线的有效轴向宽度为频率160kHz的L(0,1)模态波长的一半。利用研制的磁致伸缩传感器,在长1180mm的自由钢绞线中进行超声导波的激励接收试验。试验结果表明,该传感器可以激励和接收选定的纵向模态L(0,1),为基于磁致伸缩效应的钢绞线超声导波检测奠定了一定基础。
Excitation and reception methods of the longitudinal guided wave modes in steel strands based on magnetostrictive effect are analyzed theoretically and verified in the experiment. Propagation characteristics of longitudinal modes in a 17.80 mm nominal diameter steel strand are firstly investigated. L（0,1） mode at 160 kHz in one of helical wires is optimized for health inspection of the steel strand. Based on propagation characteristics of this mode and peripheral winding surface of steel strands, a kind of special magnetostrictive transducer is developed for ultrasonic guided wave inspection of seven-wire steel strands. The transducer mainly consists of axisymmetric three permanent bias magnetic circuits and a three-section spiral tube with reverse normal winding directions. These axisymmetric circuits are used for producing bias magnetic field with suitable and uniform strength, and the special clamp groups are designed for reducing air reluctance caused by irregular contour of steel strands. Effective axial width of each section of spiral tube equals to half wavelength of L（0,1） mode at 160 kHz. By using these developed magnetostrictive transducers,gnided wave excitation and reception are achieved in a 1 180 mm long free steel strand. Experimental results show that chosen L（0,1） mode can be excited and received by using developed magnetostrictive transducers. These transducers will provide the experimental basis for ultrasonic guided wave inspection of steel strands based on magnetostrictive effect.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2010年第6期71-76,82,共7页
Journal of Mechanical Engineering
基金
国家自然科学基金(10602004)
北京市自然科学基金(2072003)
北京市优秀人才培养资助基金(20081B0501500173)
北京工业大学博士科研启动基金(52001013200701)
北京市科技新星计划(2008A015)资助项目
关键词
磁致伸缩效应
传感器
钢绞线
超声导波
模态
Magnetostrictive effect Transducer Steel strand Ultrasonic guided waves Mode
