Structural Design And Performance Simulation Of Nanoporous Metals

Benefiting from the merits of low density,high specific surface area and high conductivity based on the unique cellular network structure,porous metals have drawn worldwide attention in terms of catalysis,sensors,fuel cells,and drug delivery.Porous metals with random structure are generally synthesized by dealloying strategy,whereas templating method is typically used to fabricate metal foams with more regular pore distribution.Moreover,with the progress of additive manufacturing(AM),porous solids can be fabricated with predefined external shape and internal architecture.The integration of dealloying,templating and AM allows for the fabrication of complex porous metals with structural hierarchy,and offers the feasibility towards rational design of such structure-function materials for specifically technological applications.This thesis consists of three parts:(1)Metal aerogels / Nanoporous metals: the metal aerogel-like models are firstly generated by Voronoi tessellation,whose geometrical parameters and mechanical properties are predicted by finite volume method;moreover,a structure-dependent analysis has been performed by comparing the behavior of tomographic reconstructed dealloying structure with Voronoi and diamond structures.(2)Gold foams: a new analytical–numerical model was used to predict the stiffness and strength of close-packed hollow-structured metal foams with structural hierarchy.The twolevel model comprises a main backbone(i.e.,hollow sphere-packing architecture)and a secondary nanoporous structure(i.e.,bicontinuous nanoporous network).(3)Structural design: four sorts of skeletal and sheet lattices are designed,taking inspire from triply periodic minimal surfaces(TPMS).The scaling laws of the geometrical parameters and mechanical properties are determined as functions of the relative density according to numerical analysis and computational simulation.Plus,an application to additive manufacturing accompanying with uniaxial compression testing is also performed,and the results show a highly agreement with the above scaling laws.