LAUSR

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.