考虑界面断裂和应变隔绝的柔性电子结构优化设计研究

Flexible electronics, capable of sustaining large deformation and matching the complex curvilinear surface, has remarkable advantage and promising application future in biological, robotic and medical fields when compared with conventional electronics. In this project, with the fabrication and serviceable condition in flexible electronics as background, we define the structural design of flexible electronics as object and establish the topology optimization model considering the interfacial competing-fracture, strain isolation, structural capability and volume constraint. With flexible layer as design domain, we develop effective algorithm to solve the zigzag movement phenomena, grey element, unstable low-density element and other optimization convergence problems, obtain the novel optimal configuration of flexible electronics responsible for lower transfer printing difficult and enhanced serviceable duration by solving the topology optimization model, and validate the optimal result with physical experiments and analyze the mechanism of corresponding viscoelastic interfacial fracture problem. Compared with existed structural design methods based on experience and trial-error, the topology optimization approach in flexible electronics considering the interfacial fracture and strain isolation is capable of systematically analyzing and reasonable designing the structure of flexible electronics, providing the yield mechanism of optimal configuration, also developing an effective structural optimization design method for flexible electronics, providing guide to the structural design of flexible electronics and pushing the development of flexible electronics.

柔性电子可承受大变形和适用复杂曲面，在生物、医学、机器人等领域具有传统电子产品无法比拟的优势和广阔应用前景。本项目工作以柔性电子的制备和使用状态为研究背景，以柔性电子结构设计为研究对象，建立考虑界面竞争断裂、应变隔绝、结构承载刚度和体积约束的拓扑优化模型。以柔性层为设计域，发展高效算法解决优化震荡迭代现象、灰度单元和低密度单元不稳定等优化收敛性问题，求解拓扑优化模型得到减小转印难度方便制备和降低应变水平提高使用寿命的柔性电子优化创新构型，并进行基于优化创新构型的物理实验验证和粘弹性界面断裂机理分析。与当前基于经验或试错法的结构设计方法相比，考虑界面断裂和应变隔绝的柔性电子拓扑优化设计可系统性分析和理性设计柔性电子结构，揭示优化创新构型产生机理，发展一套可行的柔性电子结构优化设计方法，为柔性电子结构设计提供指导，推动柔性电子发展。

柔性电子可承受大变形和适用复杂曲面，在生物、医学、机器人等领域具有传统电子产品无法比拟的优势和广阔应用前景。本项目围绕柔性电子制备和使用状态，利用解析模型、数值分析、拓扑优化和物理实验等手段，考虑界面断裂设计、界面诱导变形行为、应变隔绝设计、表面精度调控、柔性电子工程应用等开展系列研究工作。构建拓扑优化模型，给出有利于转印和降低应变水平的柔性电子创新设计，优于传统基于个人经验的结构设计。建立有限变形解析模型，给出界面诱导变形临界条件的准确预测和组装变形的精确描述，显著优于传统小变形理论和构型假设解。构建薄膜应力解析模型和拓扑优化理论，基于褶皱应力准则，给出全域张紧的薄膜创新构型，达到完全无褶皱的效果，满足工程应用苛刻的精度要求，也为薄膜褶皱问题提供了一个根本性的解决方案。考虑微流控和传感器需求，制备具有超低粘附性能的超疏水柔性界面和具有超快反应的柔性传感器，潜在应用于柔性可穿戴电子。项目执行过程中，在J. Mech. Phys. Solids、Int. J. Solids. Struct、Int. J. Mech. Sci、Nanotechnol、J. Appl. Mech等力学著名期刊上发表论文14篇，获批专利3项，项目负责人获亚洲结构与多学科优化协会ASSMO青年科学家奖和大连理工大学“星海优青”等人才项目支持。本项目研究发展了一套可行的柔性电子结构分析和优化方法，有望推动柔性电子进一步发展。