电-湿-热耦合作用下木质电热复合材料微结构力学及电热效应失效演变机制

木质电热复合材料是木材、电热膜、胶黏剂经胶合形成具有通电发热的功能材料，其薄弱层为电热层。在长期电热和湿热循环作用下电热层受到破坏引起微结构力学失效，导致木质电热制品出现局部高温碳化、损伤漏电、电热效应失效现象，严重阻碍推广应用，成为木质电热复合材料亟待解决的核心问题，而电热层微结构力学及电热效应失效演变机制是其突破技术瓶颈的科学问题。本项目以电热层微结构为研究对象，采用电热性能测试系统、原位纳米力学系统、红外成像系统及纳米粘弹性测试系统等先进技术，开展电-湿-热耦合作用下电热层微结构性能及电热效应演变研究。通过电热层微结构热稳定性、物相结构、界面力学、化学组分及电热特性变化规律研究，剖析微结构力学和电热效应衰减行为特征，阐明胶合界面损伤机理，建立微结构力学衰减与整体失效内在关联模式，从而揭示木质电热复合材料微结构力学及电热效应失效演变机制，为解决木质电热制品技术瓶颈提供数据和理论支撑。

Wood electrothermal composite is made of wood, electrothermal film and adhesive by gluing to form electrothermal function material, and its weak layer is the electrothermal layer. Under the action of long-term electric heating and humid heat cycling, the electrothermal layer is damaged and the microstructure mechanics is damaged, resulting in localized high-temperature carbonization, electric leakage, and electrothermal effect failure of the wooden electric heating products, which seriously hinders the promotion and application. These phenomena have become the key problems to be solved urgently for wooden electric heating composites, and microstructure mechanics and electrothermal effect failure evolution are the scientific problem to solve of breaking through the technical bottleneck. Therefore, the electrothermal layer microstructure is taken as the research object in this project, the failure evolution of microstructure performance and electrothermal effect under the action of electric-moisture-thermal coupling will be investigate by electrothermal test system, infrared scanning system, nanoindentation, nanoviscoelasticity test system, and so on. By studying the thermal stability, phase structure, interface mechanics, chemical composition and electrothermal characteristics of electrothermal layer microstructure, the attenuation mechanism between microstructure mechanical and electrothermal effect will be deeply analyzed, The damage mechanism of the adhesive interface will be explained, at the same time, the internal correlation model of microstructure mechanics and composite failure also will be stablished. Thus, the microstructure mechanics and electrothermal effect failure evolution of wooden electric heating composites is revealed to provide data and theory support for solving technical bottleneck of wooden electrothermal products.