单轴压缩下Ti-6Al-4V空心点阵结构的力学行为

This study has designed and manufactured Ti-6Al-4V hollow lattice specimens with different strengthening-structure distributions, namely, basic hollow lattice structure (specimen BS), hollow lattice structure strengthened at the nodes (specimen SN), and hollow lattice structure strengthened at the tube walls (specimen SW). The effects of the strengthening-structure distribution and shape parameter on the quasi-static mechanical behavior of the hollow lattice structures were investigated using experimental test and numerical simulation. The experimental results showed that compared with specimen BS, the specific elastic modulus and specific ultimate strength of specimen SN were reduced by 7% and 12%, respectively. Meanwhile, the elastic modulus, ultimate strength, and specific ultimate strength of specimen SW increased by 20%, 49%, and 13%, respectively. The collapse position of specimen SN occurred at the struts, whereas that in specimen SW was at the nodes. The different distributions of the strengthening structure induced changes in the structural weakness, stress distribution, and load-bearing capacity of the cells. Therefore, these three specimen types exhibited different failure characteristics and mechanical properties. Among the three specimens, only the strengthening structures of specimen SW reinforced the structural weaknesses and improved the load-bearing capacity of the cells. Hence, specimen SW demonstrated a significant advantage in terms of mechanical property. In addition, the numerical simulation studied the effect of the shape parameters of the strengthening structure on the mechanical property of specimen SW. The simulation results indicated that when the ratio of the strengthening-structure height to the hemi-cell height was 0.6 or that of the strengthening-structure thickness to the internal diameter of the hollow strut was 0.1875, the strengthening structure of the cells became more balanced and the loadbearing capacity became stronger than those in the other types. Therefore, based on our work, we can conclude that a reasonable structural design is conducive in obtaining a lightweight structure with superior mechanical properties.