The fundamental shear horizontal (SH0) wave, which can be generated by electromagnetic acoustic transducers (EMATs), is widely used in the structural health monitoring fields owing to its non-dispersive nature and the ability to detect over long distances. However, current SH0 wave methods hardly achieve the excellent signal-to-noise ratio (SNR) of the echo signals and satisfactory spatial resolution to defects due to the co-restriction between them. To address these issues, a spatiotemporal energy regulation strategy (STERS) is proposed in this paper to optimize energy distribution in the temporal and spatial dimensions. First, spatiotemporal pulse compression technology (STPCT) is proposed to improve both SNR and spatial range resolution for defect detection. Second, a staggered dual-exciter employing two sets of excitation signals is designed to improve the spatial azimuth resolution. Besides, a double sidelobe suppression algorithm (DSSA) is proposed to suppress sidelobe issues arising from the application of STPCT, thereby further improving the performance of STPCT. Finally, multiple simulations and experiments are executed to demonstrate the advantages of the proposed damage detection system. Results show that our methods can achieve comprehensive improvement in SNR, spatial range resolution, spatial azimuth resolution, and sidelobe suppression ability.

中文翻译：

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提高SH0波损伤检测信噪比和空间分辨率的时空能量调节策略


电磁声换能器（EMAT）产生的基本剪切水平（SH0）波因其非色散性质和长距离检测能力而广泛应用于结构健康监测领域。然而，由于两者之间的共同限制，当前的SH0波方法很难实现良好的回波信号信噪比（SNR）和令人满意的缺陷空间分辨率。为了解决这些问题，本文提出了时空能量调节策略（STERS），以优化时间和空间维度上的能量分布。首先，提出了时空脉冲压缩技术（STPCT）来提高缺陷检测的信噪比和空间范围分辨率。其次，设计了采用两组激励信号的交错双激励器来提高空间方位分辨率。此外，提出了双旁瓣抑制算法（DSSA）来抑制STPCT应用中产生的旁瓣问题，从而进一步提高STPCT的性能。最后，进行多次仿真和实验以证明所提出的损伤检测系统的优点。结果表明，我们的方法可以实现信噪比、空间距离分辨率、空间方位分辨率和旁瓣抑制能力的全面提高。