Research On Mechanical Properties Of ZrO₂ Ceramic Lattice Structures Based On DLP Additive Manufacturing

The rapid development of ceramic 3D printing(additive manufacturing)technology has greatly expanded the design space of ceramic component structures,making it possible to fabricate high-precision ceramic lattice structures with complex configuration.Among them,inspired by the configuration of natural biological structures,the ceramic lattice structure with excellent load-carrying,heat-dissipating,and wave-transmitting properties has attracted extensive attention in aerospace and other fields.However,although 3D printing technology can realize the fabrication of structures with arbitrary shapes on the technical theory level,due to the limitation of the existing additive manufacturing process level,there is still a certain deviation between the mechanical properties of structural parts manufactured by additive manufacturing and the actual predicted performance,which is more prominent for ceramic additive manufacturing technology.Therefore,it is of urgent significance to carry out research on the formation properties of ceramic lattice structures to promote the engineering application of this technology.For this reason,this paper,oriented towards the ceramic additive manufacturing lattice structures based on digital light processing(DLP)technology,conducts performance characterization research on lattice structures with different configurations,scales,levels and internal geometric parameters by combining experiments with theoretical techniques.The specific content is as follows:(1)A typical truss-type unit cell and two topology-optimized unit cells with specific design properties are selected,and the ZrO2 ceramic lattice structures are fabricated by DLP,and their mechanical performance under uniaxial compression and three-point bending is systematically studied.The results show that the unit cell with the largest bulk modulus(BLM)has the largest equivalent elastic modulus under uniaxial compressive loads,and is more suitable for compressive load cases that require high stiffness.While the body-centered cubic unit cell(BCC)has relatively balanced and stable mechanical properties.(2)The hexagonal ceramic lattice structures with different inherent geometric parameters are designed and fabricated.And the preparation accuracy and mechanical response under uniaxial compression of hexagonal ceramic lattice structures are systematically analyzed.Experimental results show that the hexagonal ceramic lattice structures exhibit the failure trend of "from outside to inside" and "from fast to slow"under uniaxial compression load.The unit cell size shows no dependence on the equivalent performance of the hexagonal ceramic lattice structures.But the number of unit cells has a significant impact on the compression performance of the hexagonal lattice structures,and its influence will show a convergence trend with the increasement of the number of unit cells.It is more obvious that when the number of unit cells is less than 5,the equivalent elastic modulus based on the experiment is significantly lower than the simulation result,but the equivalent elastic modulus is relatively stable after 5 layers.The increase in the size of the rods has a significant effect on the equivalent compression performance of the hexagonal ceramic lattice structures.(3)Based on the asymptotic homogenization method,the equivalent elastic modulus correction formulation for geometric parameters is established,which quantitatively describes the influence relationship between equivalent elastic modulus and the inherent geometric parameters of the lattice structure(unit cell number,unit cell size and rod size).The proposed correction formulation is verified by multiple sets of uniaxial compression experiments and four-point bending experiments.The results showed that the results calculated by the correction formulation are in good agreement with the experimental results,which fully confirm the effectiveness the correction formulation proposed in this paper.