摘要
针对由变截面杆构成的体心立方(Body-Centered Cubic, BCC)梯度点阵结构,推导了BCC线性变截面弯折杆弯矩的分布表达式,应用于Timoshenko梁理论,得到了梯度点阵结构的力学特性参数化理论预测模型;采用六面体实体单元建立了BCC变截面单胞单元和梯度点阵结构的有限元模型,完成了仿真分析,验证了理论预测模型的有效性.对于梯度点阵结构则采用3D打印技术并选择316L金属粉末制备试样,开展了准静态压缩力学试验,同时也完成了同样工况下的有限元仿真分析,验证了Timoshenko梁模型对于长径比10以下梯度点阵结构力学特性研究的适用性,最后通过理论模型讨论了不同长径比、单胞尺寸、单胞数量和梯度方向等各种梯度点阵结构力学特性的变化规律.研究结果表明:对于线性变截面弯折杆,文中所推导的弯矩分布更加精确,能有效降低理论解的误差;采用本文中的理论预测模型,若长径比在3.5~8.7区间内,BCC变截面单胞单元及梯度点阵结构的等效弹性模量解的误差在3%以内.
For body-centered cubic(BCC)gradient lattice structure composed of linearly variable cross-section struts,distribution of bending moments was derived.Applied to the Timoshenko beam theory,a parametric theoretical prediction model for the mechanical properties of gradient lattice structure was obtained.Using the hexahedral solid elements,the finite element models of the unit cells and the gradient lattice structure were established.Finite element analyses(FEA)were performed to verify the effectiveness of the theoretical model.For the gradient lattice structure,3D printing technology was used to fabricate the test samples using 316 L metal powders.The quasi-static compression mechanics tests were carried out,and the FEA under the same working condition was also conducted.The results verified the suitability of the Timoshenko beam model to investigate the mechanical characteristics of gradient lattice structure up to the aspect ratio of 10.Finally,the influences of varying aspect ratios,cell sizes,cell numbers,and gradient directions on the mechanical properties of gradient lattice structures were discussed.The results show that the bending moment distribution predicted by the proposed model is more accurate and with much reduced error for the bending struts with linearly variable cross-sections.Using the theoretical prediction model proposed in this paper,the relative errors of the equivalent elastic moduli of the BCC unit cells of variable cross-section and the gradient lattice structure are within 3%for the aspect ratio range of 3.5~8.7.
作者
杨鄂川
谭成帅
马婧华
李映辉
覃亮
孔垂建
YANG Echuan;TAN Chengshuai;MA Jinghua;LI Yinghu;QIN Liang;KONG Chuijian(College of Mechanical Engineering,Chongqing University of Technology,Chongqing 400054,China;School of Mechanics and Aerospace Engineering,Southwest Jiaotong University,Chengdu 610031,Sichuan,China;Chongqing Dajiang Intelligent Defense Special Equipment Co.,Ltd.,Chongqing 401320,China)
出处
《力学季刊》
CAS
CSCD
北大核心
2024年第2期401-410,共10页
Chinese Quarterly of Mechanics
基金
国家自然科学基金(52205144)
重庆市技术创新与应用发展专项重点项目(cstc2020jscx-dxwtBX0048)。
关键词
梯度点阵结构
力学特性
TIMOSHENKO梁
理论预测
gradient lattice structure
mechanical properties
Timoshenko beam model
theoretical prediction
