Static And Dynamic Compressive Behaviors Of Porous Structures Based On Triply Periodic Minimal Surface

Porous structural materials have been widely used in aerospace,ship construction,biomedical and other engineering fields because of their low structure weight,high specific strength,high specific stiffness and good energy dissipation capacity.As a new porous material,the performance of structure based on triply periodic minimal surface(TPMS)in many application fields such as weight reduction and impact resistance has attracted more and more attention.Therefore,it is very important to study the mechanical properties of TPMS structure under static compression and impact loading.Based on TPMS porous structure,the main content of this dissertation is as follows:(1)Based on four kinds of TPMS structures,12 samples were designed and manufactured by additive manufacturing.The mechanical properties of these samples under uniaxial static compression were studied by employing the experimental equipment.The reliability of the additive manufacturing equipment and experimental equipment was verified by the repeatability study.The influence of the cell size,type of TPMS and density gradient on the mechanical properties was discussed by analyzing the stress-strain curve and the deformation mode.The results show that the mechanical properties of I-WP structure under static compression are the highest among all the TPMS structures.The reasonable gradient setting can effectively reduce the influence of initial fracture and decrease the initial peak stress.(2)The finite element model of TPMS porous structure was constructed.The mechanical properties of TPMS porous structure under quasi-static compression were studied by using the ABAQUS software.The rationality of finite element model and the reliability of simulation results were verified by comparing with the experimental results.The influence of relative density,topological forms and variation range of density gradient on the mechanical properties was studied.The results show that by increasing the relative density,TPMS structure can obtain a higher compressive strength and energy dissipation capacity.The compressive performance of gradient structure is better than the non-gradient structure when at the higher strain.Increasing the range of density gradient can enhance the advantage of gradient structure.(3)The finite element model of TPMS porous structure under impact loading was constructed.The dynamic responses of TPMS structures with different loading velocities,surface topology and density gradient were studied.The concept of Voronoi porous foam was introduced.The dynamic responses of TPMS porous structure and Voronoi foams were analyzed and compared.The results show that under dynamic loading,the stress level of TPMS structure at the fixed side is significantly lower than the impact side.It indicates that TPMS material can reduce the influence of impact loading and effectively protect the structure behind.When compared with the Voronoi foams,the energy dissipation capability of Diamond structure and non-gradient I-WP structure is better than Voronoi foams.The energy dissipation capacity of TPMS structures with other surface topology is worse than Voronoi foams.This work can deepen the understanding of the mechanical response and deformation mechanism of TPMS porous structure under static/quasi-static and dynamic loadings.It provides technical support of TPMS structure for the potential application in ship.