摘要
提出了一种拉伸-扭转耦合变形的新型力学超结构,该结构可在轴向拉伸的同时显著提升其截面扭转能力。针对这种简单构型的力学超材料胞元结构进行了建模,并通过胞元堆叠的方式设计了具有拉伸-扭转耦合变形能力的宏观梁结构。通过有限元分析方法研究了胞元的拉伸刚度和拉伸-剪切变形耦合特性,验证了宏观梁结构的变形性能并分析了相关参数,采用激光选区烧结(SLS)技术制备样品进行了实验验证。结果显示:四胞元悬臂梁的扭转角明显大于双胞元悬臂梁,在46.69 N拉力作用下,它们分别产生了0.667°和0.479°的扭转角,与有限元分析结果具有较好的一致性。此外,相比于双胞元悬臂梁,四胞元组合堆叠悬臂梁在质量上仅增加了2.77%,但耦合系数却增大了42.97%,这表明四胞元堆叠悬臂梁具有更优的拉伸-扭转耦合特性。宏观梁结构中的扭转变形近似成线性累积,可通过增加胞元组合的堆叠次数增大其扭转角。
Objective Morphing aircrafts can change their shape according to different flying environment and conditions,which makes their aerodynamic efficiency much better than traditional aircrafts.In order to achieve multidimensional deformation,mechanical metamaterials that exhibit designable morphing capability have been widely studied.Particularly,structures with coupled tension‒tsist characteristics are necessary in case that attacking angle should be changed to adjust the aerodynamic load distribution on the wing surface.Therefore,this study proposes a novel metamaterial structure that can exhibit coupled tension‒twist deformation,which significantly increases the twisting angle of a cross section under axial loading.The methodology of this study can provide valuable guideline for the future design of morphing aircrafts.Methods Models of the metamaterial cell structure were built using beam elements.Two types of beam structures with different coupled tension‒twist properties were designed by cell stacking.The stiffness and coupled tension‒shear deformation of the cells were studied by finite element analysis(FEA).After the cells were stacked,the coupled tension‒shear deformation of the cells transformed into coupled tension‒twist deformation of the beam structures.The deformation capabilities of the beams and related parameters were then investigated.Finally,samples of different lengths of two types of beams were prepared by selective laser sintering(SLS)of PA12 material for experimental verification.Samples were loaded by hanging weights on the free end,and the other end was fixed by an industrial bench vice.The twist angle was measured indirectly using a laser sensor.Results and Discussions The beams were designed with the ability to exhibit coupled tension‒twist deformation with a twist angle higher than 15°.Results show that the twist angle of the four cells combination cantilever beam is significantly greater than that of the two cells combination cantilever beam.Under a tensile load of 46.69 N,t
作者
朱学仁
黄可
陈玮
张家应
Zhu Xueren;Huang Ke;Chen Wei;Zhang Jiaying(National Key Laboratory of Science and Technology on Power Beam Processing,AVIC Manufacturing Technology Institute,Beijing 100024,China;School of Aeronautical Science and Engineering,Beihang University,Beijing 100190,China)
出处
《中国激光》
EI
CAS
CSCD
北大核心
2024年第10期178-186,共9页
Chinese Journal of Lasers
基金
国家自然科学基金(92271104,12102017)
北京市自然科学基金(1232014)。
关键词
超材料
结构设计
胞元堆叠
增材制造
metamaterial
structure design
cell stacking
additive manufacturing
