【摘要】 针对电磁超声兰姆波换能器激发的兰姆波存在多模式、频散现象和信号较弱的问题,结合铝合金板材检测背景,提出一种基于"双交点法"、"零斜率准则"和正交试验设计相结合的电磁超声兰姆波换能器多目标优化设计方法。其中,"双交点法"可有效削弱兰姆波多模式现象的影响,"零斜率准则"能够有效降低兰姆波的频散现象,而正交试验设计方法可有效提高电磁超声兰姆波信号的幅值。依据所提优化设计方法,对一个在铝板检测中常用的电磁超声兰姆波换能器的9个主要参数进行了多目标优化设计。实验表明,优化后,兰姆波信号中的多模式、频散现象得到显著抑制,而且信号幅值得到明显提升,有效改善了电磁超声兰姆波换能器的工程实用性。更多还原

【Abstract】 To minimize the multi-modes and dispersion phenomena and to enhance the signal strength of Lamb wave Electromagnetic Acoustic Transducer(EMAT),this paper proposes a multi-objective optimization method for Lamb wave EMAT based on the combination of the "two-intersection-points" method and "zero-slope" criterion with the orthogonal test method.The "two-intersection-points" method and the "zero-slope" criterion can effectively minimize the influence of multi-modes and the dispersion phenomena of Lamb waves respectively;and the orthogonal test method is able to enhance the signal strength of Lamb wave signals.Nine prime parameters of a Lamb wave EMAT which is commonly used for the inspection of aluminum plates are optimized based on the proposed multi-objective optimization method.Experiments show that after optimization,not only the multi-modes and the dispersion phenomena are notably depressed,but also the signal strength is greatly enhanced,which significantly improves the practicability of the transducers.更多还原