基于拓扑优化的新型蜂窝结构设计

Design of new honeycomb structure based on topology optimization

可变体飞行器若要实现机翼后掠角、面积和前后缘弯度等参数的大幅度变化,机翼蒙皮需要具有光滑的气动外形、大变形、高承载以及驱动力小的特点。针对柔性蒙皮的需求,本文利用拓扑优化方法设计了一种新型零泊松比蜂窝结构,通过有限元仿真与U形蜂窝结构和余弦形蜂窝结构进行对比,验证其变形和承载等性能。以最大应变2%为基准,比较了三种蜂窝结构的变形能力。结果表明,新型蜂窝结构的拉伸变形量高达75%,分别是U形蜂窝结构和余弦形蜂窝结构的1.7倍和2.1倍。在最大位移量相同时,所需驱动力分别是U形蜂窝结构和余弦形蜂窝结构的0.51倍和0.28倍,表明新型蜂窝结构具有很大的易变形能力。当蜂窝结构的橡胶蒙皮受到相同压强载荷且处于初始未拉伸状态/拉伸状态时,新型蜂窝结构橡胶蒙皮的最大法向位移量分别是U形蜂窝橡胶蒙皮和余弦形蜂窝橡胶蒙皮的0.4倍/0.56倍和0.29倍/0.42倍,表明新型蜂窝结构具有良好的面外承载能力。另外,通过适当增加壁厚,可以提高新型蜂窝结构本身的抗弯曲能力。分析结果表明,本文设计的新型蜂窝结构具备大变形、高承载以及驱动力小的优点。

For deformable aircraft to achieve large changes in wing sweep angle,area,and leading and trailing edge curvature,the wing skin should have a smooth aerodynamic shape,allow large deformation,and have a high load capacity and small driving force.Aiming at the demands of a flexible skin,a new zero possion’s-ratio honeycomb structure is designed by a topology optimization method,and the performance of the structure is verified by a finite element analysis and compared with a U-type honeycomb structure and cosine honeycomb structure.The deformation capacity of three structures is compared with the maximum strain of 2%.The tensile deformation of the new honeycomb structure is up to 75%,which is 1.7 times that of U-type honeycomb structure and 2.1 times that of the cosme-type ycomb structure.The new honeycomb structure has high deformability.When the maximum displacement is the same,the required driving force is 0.51 times and 0.28 times of the U-type structure and the cosine-shaped honeycomb structure,respectively.The new honeycomb structure has a high load capacity.When the rubber skin of the honeycomb structure is under the same pressure load and in the initial unstretched state or stretched state,the maximum normal displacement of the new honeycomb structure skin is small,which is 0.4 times or 0.56 times that of the U-type honeycomb structure skin,0.29 times or 0.42 times that of cosine honeycomb structure skin.In addition,by appropriately increasing the wall thickness,the bending resistance of the new honeycomb structure can be significantly improved.Analysis results show that the new honeycomb structure designed in this paper has the advantages of high deformability,high load capacity and low driving force.