薄壁曲面类开孔结构的形状优化设计理论与方法研究

现有形状优化方法主要针对平面结构轮廓与实体结构曲面外形轮廓的优化设计,设计变量可方便、自由定义。然而，航空航天存在大量薄壁曲面类开孔结构，其设计形式、相关设计理论与方法的先进性直接影响系统的整体性能和承载能力。本项目建立了参数映射和虚拟打孔两套优化设计新方法，提出了在曲面内部参数坐标平面显式定义孔形几何设计变量和使用CAD布尔运算隐式描述轮廓外形的新思路，从根本上保证了孔形轮廓曲线与曲面贴合的几何协调性，突破了现有形状优化方法的局限性。同时，通过研究曲面曲率的影响，揭示了曲面结构与已往平面结构形状设计方法的统一性，为航空航天大量薄壁曲面类开孔结构的强度设计建立了有效的方法。.此外，针对工程中薄壁曲面类结构的加筋与开口等典型结构特征，提出几何形状与加筋布局设计参数的协同优化方法。以减轻结构重量为目标，充分考虑机械承载、失稳屈曲、结构振动等不同工况要求，通过力学实验验证，形成系统性研究成果。

Existing shape optimization methods are mainly focused on the contour designs of planar structures and solid structures for which design variables can easily be defined and freely changed. However, thin-walled curved structures with cutouts are very popular in aerospace engineering. Their design solutions and the advances of related design theories and methods are essential to the overall performance and load-bearing capacity. Two new methods, i.e., parametric mapping method and virtual punching method are developed in this work. Geometric design variables related to the cutouts are defined either explicitly in the intrinsic coordinate system of the curved surface or implicitly through CAD Boolean operations. Both new approaches make it possible to ensure the attachment of the hole contour onto the specific surface. Meanwhile, by analyzing the influence of surface curvature, both curved surface structures and planar structures can be dealt with in a unified way. This provides an efficient methodology for the strength design of thin-walled curved structures with cutouts found widely in aerospace engineering..Besides, considering typical openings and reinforcements of this kind of engineering structures, we propose a simultaneous shape and reinforcement layout optimization method with different kinds of design variables. With the help of experiments, the objective of this work is to reduce the structural weight under mechanical loads, buckling and vibration constraints for the achievement of a systematic study.