We propose a new approach for assessing microstructural properties of materials via nondestructive testing (NDT). This approach lies on the observation that, accounting for the microstructure within the materials, reveals a nonclassical band propagation pattern for Love waves. Precisely this propagation structure may be directly related to the internal microstructure. To illustrate this, propagation of Love waves is first investigated within the linear theory of couple stress materials with micro-inertia. Proving wave existence by the argument principle provides a closed-form condition for propagation to occur. This connection defines propagation bands, whose limits correspond to the situation when Love waves move with the same speed as bulk waves in the underlying half-space (internal resonance). This condition is closely related to the layer-to-substrate microstructure and it may be used to assess either of the two. Furthermore, we show that the frequency equation is a three-term combination of antiplane Rayleigh and Rayleigh–Lamb functions (in a free and in a free/clamped plate). Consequently, investigation of any extra observable, such as Rayleigh waves, reduces the risk of multiple solutions at the signal processing stage. We finally consider the limit as either the half-space or the layer becomes classical elastic. We show that this unseemly bonding of dissimilar models, sometimes adopted in the literature, usually leads to inconsistencies.

我们提出了一种通过无损检测 (NDT) 评估材料微观结构特性的新方法。这种方法基于观察，考虑到材料内的微观结构，揭示了洛夫波的非经典带传播模式。准确地说，这种传播结构可能与内部微观结构直接相关。为了说明这一点，首先在具有微惯性的耦合应力材料的线性理论中研究了洛夫波的传播。通过论证原理证明波的存在为传播发生提供了一个封闭形式的条件。这种联系定义了传播带，其限制对应于洛夫波在底层半空间（内部共振）中以与体波相同的速度移动的情况。这种情况与层到基板的微观结构密切相关，可用于评估两者中的任何一个。此外，我们表明频率方程是反平面瑞利和瑞利-兰姆函数的三项组合（在自由和自由/夹紧板中）。因此，研究任何额外的可观测值，例如瑞利波，可以降低信号处理阶段多重解的风险。我们最终将极限视为半空间或层成为经典弹性。我们表明，有时在文献中采用的不同模型的这种不合时宜的结合通常会导致不一致。我们表明频率方程是反平面瑞利和瑞利-兰姆函数的三项组合（在自由和自由/夹紧板中）。因此，研究任何额外的可观测值，例如瑞利波，可以降低信号处理阶段多重解的风险。我们最终将极限视为半空间或层成为经典弹性。我们表明，有时在文献中采用的不同模型的这种不合时宜的结合通常会导致不一致。我们表明频率方程是反平面瑞利和瑞利-兰姆函数的三项组合（在自由和自由/夹紧板中）。因此，研究任何额外的可观测值，例如瑞利波，可以降低信号处理阶段多重解的风险。我们最终将极限视为半空间或层成为经典弹性。我们表明，有时在文献中采用的不同模型的这种不合时宜的结合通常会导致不一致。