In-situ synchrotron X-ray tomography investigation of the imperfect smooth-shell cylinder structure

Lattice materials at micro scale with extraordinary stiffness and strength have demonstrated promising industrial application potentials in aerospace, transport, automotive, biomedical and other sections. However, the complex fabrication process at micro scale will inevitably induce stochastic geometric defects within as-fabricated lattice materials, thus quantitatively evaluation of the mechanical integrity of 3D-printed micro lattice structures becomes a critical important issue. In this paper, mechanical behavior of the micro Schwarz Primitive triply periodic minimal surfaces (P-TPMS) cylinder shell structures fabricated with projection micro-stereolithography (PμSL) 3D printing technique were investigated. Meanwhile, synchrotron X-Ray micro-tomography (SR-μCT) 3D imaging and interrupted in-situ compression experiment were employed for quantifying the effect of defects on the compression mechanical performances. It is found that the thickness along vertical direction was larger than along horizontal direction. Afterwards, three different types of finite element models were developed for understanding the effects of fabrication defects on the mechanical behavior characteristic. Simulation results demonstrated that the statistical model was more accurate and efficient when compared with the ideal model and real geometry reconstructed model. Finally, parametric study was also presented to gain insight into the role of thickness imperfections on the mechanical performance of the shell.