Study On Geometric Modeling Algorithm Of Closed-cell Metal Foam With Random Cell Distribution

Closed-cell metal foam is widely used in explosion-proof,bulletproof,impact and other engineering fields due to its excellent energy absorption characteristics.Computer numerical simulation technology provides a new way to study mechanical properties of porous foam.The accurate and reasonable meso-geometric model of closed-cell metal foam and the finite element model is the key link to simulate and study the mechanical properties of the material and its structural parts.In this paper,the three dimensional geometric models of traditional aluminum foam and composite metal aluminum foam were constructed respectively to characterize the characteristics of mesoscopic pore structure.At the same time,the deformation failure process of the traditional aluminum foam and the composite metal aluminum foam under quasi-static uniaxial compression was analyzed respectively.Finally,the mechanical properties such as the compressive stress-strain curves were obtained.Firstly,a random point uniform optimization algorithm based on Voronoi was proposed.The decatrahedron model and Voronoi optimization model with uniform cell were constructed automatically by creating the algorithm script.The length of equilateral triangle,the key parameter of single cell decahedron in the model,is set as the adjustable variable to create the geometric model of the decahedron quickly and efficiently.The Voronoi cell body uniformity optimization model is an improvement of the traditional Voronoi model and its cell body size is more uniform,which is consistent with the meso-structure characteristics of metal foam with roughly uniform pore size.Secondly,a random point minimum distance optimization algorithm is proposed.The geometrical models with equal diameter holes and random uniform distribution of spheres with wall thickness were developed on the ABAQUS platform.Using this modeling method,the geometric model of composite metal foam with high porosity can be quickly generated.Parameters such as model boundary,the number of random points,the cell hole size and the wall thickness in the modeling process were integrated as a whole to successfully construct the geometric models with random uniform distribution of spherical holes with different geometric shapes and gradients to characterize the cellular structure of composite metal foam with high porosity.And the corresponding user modeling graphical interface window was developed to provide modeling tools for the creation of other spherical particle reinforced composite foam with similar meso-structure characteristics.Finally,by combining experiment and finite element analysis methods,the feasibility and accuracy of the geometrical models constructed in this paper was verified.At the same time,the deformation failure process of the traditional aluminum foam and the composite metal aluminum foam under quasi-static uniaxial compression was analyzed respectively and the compressive stress-strain curves and mechanical properties were obtained.The finite element model under uniaxial compression of traditional aluminum foam and the composite metal aluminum foam model were constructed respectively by using the tetrahedral model and the random uniform distribution model of the spheres based on the Voronoi random point minimum distance optimization algorithm.The Simulation and experimental results show that the stress-strain curves are roughly consistent.As a result,the feasibility and accuracy of the established geometric models are verified.During the process of compression,it was found that the buckling deformation of the pore wall occurred mainly in the traditional aluminum foam,while the plastic folding deformation of hollow metal spheres occurred mainly in the composite metal aluminum foam and the deformation of the latter is more uniform than that of the former.The compressive stress-strain curves of both traditional aluminum foam and composite aluminum foam show the characteristics of typical elastoplastic foam.The platform stage of plastic buckling of the latter is longer and the corresponding platform stress is higher.It shows that the composite metal aluminum foam has higher compressive mechanical properties and higher strength,bearing capacity and energy absorption effect than the traditional aluminum foam.