随着器件功能化和小型化的发展，多铁性复合材料/结构因具有多重物理属性而作为新一代多功能材料在新型器件设计中得到广泛关注。当结构尺寸减小到微纳米时，材料的挠曲电性会显著增强结构的磁电耦合效应，其宏观力学行为也有明显的变化，而传统的连续介质力学理论已无法对此进行有效预测。本项目针对多铁性复合材料/结构，考虑挠曲电性的影响，采用级数展开技术系统建立一维和二维简化结构理论。在此基础上，研究纳米尺度多铁性复合材料/结构的宏观力学行为，分析其磁电效应，并确定影响结构宏观力学行为和磁电效应的关键参数。针对特定工作模式，推导器件主要设计参数的计算公式，为器件的研发、设计和使用提供直接的理论指导。本项目拓展了连续介质力学的研究范围，在一定程度上发展了多场耦合力学的分析方法，既有重要的理论价值，又有明确的工程应用背景。

Multiferroic materials simultaneously exhibit several ferroic (e.g. ferroelectric, ferromagnetic, or ferroelastic) orders, have drawn increasing attentions duo to their potential for applications as new micro- or nano- multifunctional devices. At the nanoscale, flexoelectriciy obviously changes macro-mechanical behaviors of multiferroic materials and dramatically enhance its magnetoelectric effects as well. However they cannot be precisely pridicted by using the traditional continua media theory. The project will take into account the flexoelectricity to develop a systematic simplified structural theory for nanoscale multiferroic materials based on the power series expansion method. With the developed theory, we will investigate the mechanical properties and the magnetoelectric effects of nano-multiferroic materials/structures, then put forward the key design parameters for some representative devices and deduce their effective computing formulas. The outcome of the project can extend the research scope of the traditional continua media theory and make a certain extent progress in the multi-field coupling mechanics, which not only has important theoretical value but also strong background in device applications.