| 王志春,袁伟.基于COMSOL连铸坯壳测厚横波EMAT优化[J].声学技术,2018,37(3):237~242 |
| 基于COMSOL连铸坯壳测厚横波EMAT优化 |
| COMSOR based shear wave EMAT optimization for thickness measurement of continuous casting shell |
| 投稿时间：2017-05-25 修订日期：2017-07-18 |
| DOI：10.16300/j.cnki.1000-3630.2018.03.008 |
| 中文关键词: 连铸坯壳 电磁超声换能器 横波 测厚 有限元建模 |
| 英文关键词: continuous casting shell electromagnetic acoustic transducer transverse wave thickness measurement finite element model |
| 基金项目:国家自然基金项目（61463041） |
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| 中文摘要: |
| 为了研究电磁超声传感器（Electromagnetic Acoustic Transducer，EMAT）横波测量连铸坯壳厚度的机理及横波在连铸坯中的传播情况，选取坯壳厚度为10~50 mm的Q235小方坯为研究对象，利用有限元软件COMSOL建立脉冲电磁铁和螺旋线圈的电磁超声模型，分析在不同EMAT结构参数下，连铸坯中电磁场、力场、声场的分布规律。研究结果表明：脉冲电磁铁和螺旋线圈组成的EMAT能够在连铸坯壳集肤层激发出超声波横波。脉冲电磁铁空心螺线管线圈匝数、内半径、线圈导线半径对换能效率的影响依次减小，且当脉冲电磁铁内半径尺寸大于螺旋线圈尺寸时，产生横波的效率最高。坯壳厚度越小，螺旋线圈最优激励频率越大，测量精度越高，信号衰减越快。因此，坯壳厚度为10~50 mm的Q235小方坯选择1.1 MHz为最佳激励频率。 |
| 英文摘要: |
| In order to study the mechanism and propagation of the shear wave generated by EMAT (electromagnetic acoustic transducer) in continuous casting shell, the Q235 billet with shell thickness of 10~50 mm is taken as the re-search object. The electromagnetic ultrasonic model of pulsed electromagnet and spiral coil is established by using the finite element software COMSOL. The distributions of electromagnetic field, force field and sound field in continuous casting slab under different EMAT parameters are analyzed. The results show that the EMAT made by the combination of the pulse electromagnet and the spiral coil can excite the ultrasonic shear wave in continuous casting shell. The effects of the coil winding number, inner radius, and radius of coils on the transfer efficiency decrease in turn. When the radius of the pulse electromagnet is larger than the size of the spiral coil, the efficiency of generating transverse wave is the highest. The smaller the thickness of the shell causes the higher the optimal excitation frequency, the higher the precision and the faster the attenuation. The frequency of 1.1 MHz is chosen as the optimum excitation frequency for the Q235 billet with the shell thickness of 10~50 mm. |
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