Effect of Unit Cell Topology on Dielectric Properties of Periodic Lattice Materials Used for Functionally Graded Insulation

Periodic lattice material (PLM) is an innovative material system capable of rapidly and efficiently constructing functionally graded materials (FGMs). Among various PLM structures, triply periodic minimal surfaces (TPMS) exhibit numerous advantages, making TPMS-based lattice materials a potential candidate to electrical FGMs. However, the dielectric properties of TPMS lattice materials remain unclear. A comparison between TPMS lattice and conventionally-utilised lattice materials is requested. To investigate the influence of lattice cell topology on the dielectric properties of PLMs, simple cubic (SC) and gyroid TPMS lattice materials were fabricated. Experimental results on dielectric spectroscopy and breakdown strength revealed that with the increase of feature parameters of lattice geometry, the relative permittivity decreased and breakdown strength increased for both SC and gyroid PLMs. Despite this similar tendency, the relative permittivity of Gyroid lattice is 27.1%–54.2% higher than that of SC samples with identical feature parameters, and the breakdown strength (Weibull scale parameter) of Gyroid is 20.4%–25.3% higher than SC lattices. These results indicate that the Gyroid TPMS has better applicability in lattice based FGM insulation, due to their higher permittivity and better performance in electrical breakdown strength.