Mechanical Characteristics of Variable Cross-Section BCC Gradient Lattice Structures Based on Timoshenko Beam Model
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 316L 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.
万方数据
维普
