Abstract Because it lacks sufficient descriptive power regarding the appropriate scale effect, conventional continuum mechanics is not applicable to the rapidly developing field of micro-nanoscale structures and devices. To accurately describe the scale effect on multi-scale structures, a number of high-order medium theories have been developed, with micropolar theory being the most prominent. However, because micropolar theory lacks a clear definition of the boundary displacement distribution, researchers have reached disparate conclusions regarding the scale dependence of the mechanical behaviour of heterogeneous materials. The goal of this study was to experimentally verify which set of conclusions was most accurate and determine the rationality of applying micropolar theory to micro-nanoscale structures. To achieve this, a series of three-point bendings were carried out in accordance with micropolar theory, with the experimental results confirming the scale effect in several heterogeneous micropolar medium materials. In addition, the law governing the micro-element relative rotational angle was further analysed, and further analysis of the scale effect in the micropolar medium material validated the applicability of micropolar theory to the analysis of the mechanical properties of such materials.

中文翻译：

---

异质微极介质材料力学性能尺度效应的实验研究

摘要 由于对合适的尺度效应缺乏足够的描述能力，常规连续介质力学不适用于快速发展的微纳米结构和器件领域。为了准确描述多尺度结构的尺度效应，已经发展了许多高阶介质理论，其中以微极理论最为突出。然而，由于微极理论缺乏对边界位移分布的明确定义，研究人员对异质材料力学行为的尺度依赖性得出了不同的结论。本研究的目的是通过实验验证哪组结论最准确，并确定将微极理论应用于微纳米结构的合理性。为了达成这个，根据微极理论进行了一系列三点弯曲，实验结果证实了几种异质微极介质材料的尺度效应。此外，进一步分析了微元相对旋转角的规律，进一步分析了微极介质材料中的尺度效应，验证了微极理论在分析此类材料力学性能方面的适用性。