Research On Geometry Modeling For Closed Cell Foam Material And Its Application

Closed cell foam material has a broad application prospects and remarkableadvantages in the field of modern industrial technology by virtue of its characteristics ofhigh specific stiffness, high specific strength, light weight. It’s preparation technology andmechanical property have been the focus of attention scholars.In order to study closed cellfoam material geometric modeling issues, here on the basic of aluminum foam, we imitatemelt-foaming mechanism and process, putting forward an ellipse (or ellipsoid) hole fillingVoronoi cell body EFIVC geometric modeling method, solving the transition of porewall thickness at the junction of cell walls, providing geometric modeling of closing tothe actual situation for compressive test, impact energy absorption and insulationperformance, enhancing the authenticity of numerical simulation. The main researchcontent is as follows:(1) EFIVC geometric modeling algorithm of closed cell foam material. ConstructVoronoi polygons (polyhedrons) centered on seed points, imitating melt-foamingmechanism and the process of cell growth, filling a hollow ellipse (ellipsoid) in everypolygon (polyhedron), establishing foam cell body. Set the geometrical size of Ellipse(ellipsoid) as design variable, seting the smallest foam cell body as objective function,seting disjointing ellipse (ellipsoid) and polygons (polyhedrons) as constraint condition,establishing geometry optimization algorithm of foam cell body. Use the quasi-Newtonmethod for solving, obtaining data structure of hollow cell body, completing EFIVCgeometric modeling of2D and3D.(2) Compressive deformation numerical simulation bases on EFIVC geometricmodeling. Establish a relationship between the smallest wall thickness and porosity,using EFIVC algorithm to create geometric modeling of closed cell foam material withdifferent porosity. Through compressive deformation numerical simulation in MSC.Marc,analyze how porosity, the size of hole, the rate of loading and the size of sample impactE/Es and stress-strain.(3) The preparation of aluminum foam and compressive deformation verified test.Aluminum foam is prepared by the method of melt foaming which chooses TiH2as foaming agent and Mg as thickener. Closed cell aluminum foam with better-shape anduniform pores was obtained after several experiments by adjusting the temperature,holding time, the proportion of foaming agent and thickener. Then do compressive test onWDW-3100electronic universal testing machine and compare the extracted stress-straincurve with the simulation results. Finally draw a conclusion that it has good agreementand it is reliably by using EFIVC algorithm to establish finite element model..(4) Gradient foam material model based on and Gibson’s gas phase enhancementmechanism. By controlling the distribution of Voronoi seeds in the discrete region,construct gradient aluminum foam model, providing a new method for gradient foammaterial numerical simulation. Based on Gibson’s gas phase enhancement theory, createcompressive deformation model by EFIVC algorithm, filled expansion pressure(0.01MPa、0.1MPa、0.5MPa、1MPa、1.5MPa) in the internal ellipse of the closed cell foammaterial. The simulation result show that yield stress, plateau stress and the ability to resistdeformation enhance with the increase of the internal pressure, revealing gas phaseenhancement mechanism of closed cell foam material.The issue studies numerical of the mechanical properties in closed cell foam materialand provides a new numerical simulation model for the development of new type foammaterial.