考虑几何非线性的软硬异质多层结构可靠性拓扑优化方法研究

Soft-hard integrated multi-layer (SHIML) structures are ubiquitous in biological materials, and are recently applied to the design of bioinspired composite materials and structures of soft electronics. Due to the property of soft phase, SHIML structures usually undergo large displacement upon loading; besides, due to the limit of manufacturing techniques, extensive uncertainties exist in the SHIML structures including material properties, geometrical dimensions and interfaces, and the uncertainties especially those at material interfaces are hard to model. In this project proposal, aiming at the large deformation characteristics and reliability-based design difficulties of SHIML structures, we first define a model to describe their uncertainties and carry out the reliability-based analysis of SHIML structures based on nonlinear structural analysis under large deformation. Then, a reliability-based topology optimization model will be established for SHIML structures with the help of multi-phase level set method. Subsequently, based on the combination of efficient surrogate model and improved single-loop method, an efficient reliability-based topology optimization method for geometrically nonlinear SHIML structures will be developed. Finally, the developed method will be applied to the topology optimization design of bioinspired composite structures and structures of stretchable electronics; moreover, a universal code will be written. The present project can provide methodological support for the design of soft-hard integrated high-performance, multi-functional and even intelligent composite materials/structures/devices, and enrich the existing reliability-based topology optimization methods, which has large theoretical significance and important application value.

软硬异质多层结构在生物材料中广泛存在，近年来被用于仿生复合材料和柔性电子器件的设计中。由于软材料的特性，软硬异质结构受载时往往发生较大变形；同时，由于制造工艺的限制，软硬异质结构中存在材料属性、尺寸和界面等大量不确定性，尤其是材料界面处的不确定性难以建模。本项目将针对软硬异质多层结构的大变形特点及其可靠性设计问题，首先建立其不确定性描述模型，并结合大变形下的结构非线性响应分析开展其可靠性分析，再借助多相水平集法形成软硬异质结构的可靠性拓扑优化模型；然后，基于高效代理模型和改进的单循环法建立几何非线性下软硬异质多层结构的高效可靠性拓扑优化方法；最后，将所建立的方法应用于仿生复合结构和可延展电子器件结构的拓扑优化设计，并编制通用性软件平台。本项目研究可为软硬融合的高性能、多功能以及智能化复合材料/结构/器件的设计提供方法支撑，同时丰富现有的可靠性拓扑优化方法，具有重要的理论意义和应用价值。

针对几何非线性下软硬异质结构可靠性拓扑优化存在的不确定性难以建模和计算成本大等困难，本项目通过软硬界面观测研究了软硬异质结构的不确定性描述方法，并针对软硬异质结构大变形特点，基于几何非线性分析和不确定性描述建立了软硬异质多层结构的可靠性分析模型，进一步结合多材料水平集法得到了软硬异质多层结构的可靠性拓扑优化分析模型；研究了高效高精度的自适应kriging代理模型，建立了基于kriging模型的可靠性分析方法，进一步结合自适应径向基重要抽样等高效抽样方法形成了可靠性拓扑优化的高效计算方法；将所建立的方法应用于仿生软硬融合负泊松比结构和软硬异质多层高性能复合结构的优化设计，并开发了软件平台框架以促进所建立方法的推广应用。通过项目研究，能够为软硬或多材料融合的高性能复合材料/结构/器件的设计提供参考和技术支撑。