In this paper, we discuss the observation of simultaneously propagating dual-mode second-harmonic fundamental symmetric (s₀) mode and a vertical-shear horizontal (sh₀^⊥) mode generated on an aluminium plate of 1 mm thickness while excited with a fundamental shear horizontal (SH₀) mode in a large domain. The experimental observations, and numerical models, were used to confirm the presence of dual-mode second-harmonics. The two wavemodes would separate from each other in the time-domain, wherein the travel length exceeded a minimum cut-off length of 40λ. This approach can provide important implications for more versatile early state defect detection.

中文翻译：

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观察各向同性非线性弹性板中的双模二次谐波产生

在本文中，我们讨论了在 1 mm 厚的铝板上同时传播双模二次谐波基本对称 (s ₀ ) 模式和垂直剪切水平 (sh ₀ ^⊥ ) 模式的观察，同时用基波激发大域中的水平剪切 (SH ₀ ) 模式。实验观察和数值模型用于确认双模二次谐波的存在。两种波模将在时域中彼此分离，其中传播长度超过了 40λ 的最小截止长度。这种方法可以为更通用的早期状态缺陷检测提供重要意义。