| Porous metal is a new kind of material which has the advantages of low relatively density,high specific intensity and area,low weight,good energy absorption ability,good heat and fire resisting properties,perfect shock resistance and so forth.It can be used as functional material as well as structural material.So it has been used in different field widely including transportation,sea carriage,biomedical and construction because of the functional and structural properties of the porous metal.The applying field of porous metal has been limited as its low strength.As a result it is always used through making sandwich structure.It is common to make sandwich structure through connecting the high strength surface layer with porous metal core.And then the surface layer and core bear load together just like the sandwich structure.A new kind of integrated composite structure has been proposed which is the integrated composite sandwich panel of porous metal and epoxy resin.The upper and lower layers of the structure are porous-epoxy resin interpenetrated composite layers,and the middle core is the porous metal.This composite sandwich panel’s core and surface layers are connected into a whole without any obvious interface.The overall performance is greatly improved.Composite sandwich panels of aluminum foam or honeycomb and epoxy resin are made on the basis of researching the preparation technology.The elastic stiffness,yield stress,ultimate bearing load,mechanism of deformation and energy absorption ability are studied through compression,bending,indentation and impact tests..Compression,three-point bending and four-point bending tests have been conducted with composite sandwich panel of aluminum foam and epoxy resin which has different height of composite layer.The influence of composite layer on compression mechanical properties has been studied through compression stress-strain curves.The influence of different parameter on mechanical properties including bending stiffness,energy absorption ability and flexural bearing capacity has been analyzed through force-displacement curves,it is also compared with traditional aluminum sandwich panel.The results indicate that the compression yield load,stiffness and bending bearing capacity are improved with the increase height of composite layer.Compared with traditional aluminum sandwich panel,the integrated composite sandwich panel is not easy to crack and also has the advantages of good integrality and resistance to corrosion properties.The indentation mechanical properties of two kinds of composite sandwich panels are studied through quasi-statistic tests which are integrated composite sandwich panel of aluminum foam and epoxy resin and integrated composite sandwich panel of aluminum honeycomb and epoxy resin.The typical failure mode and force-displacement curves are obtained.The mechanism of destruction is analyzed and compared with traditional sandwich panels.The influence of composite layer height,indenter types and boundary conditions on elastic stiffness,ultimate load and energy absorption ability of integrated composite sandwich panel of aluminum foam and epoxy resin has been studied.The influence of composite layer height,indenter,aperture,indenter types and boundary conditions on ultimate load and energy absorption ability has been research.The results demonstrate that the integrated composite sandwich panel of porous mental and epoxy resin has perfect integrality,stability,bearing capacity and energy absorption ability.Also the composite layers and core doesn’t crack under quasi-statistic indentation.The dynamic mechanical properties of two kinds of integrated composite sandwich panel were invested through drop weight impact test.The force-time curves and energy-time curves were obtained.The influence of different impact velocities and impactor shapes on impact force and energy absorption capacity was analyzed.The test results show that these kinds of sandwich panel of porous metal and epoxy resin show good integrity and stability under impact load.There is no peeling-off between composite layer and core materials under impact load.The macroscopic mechanical characteristics of composite sandwich beam and panel of porous metal and epoxy resin were calculated and analyzed by using RTZ,a kind of higher order deformation beam theorem and ANSYS finite element software.Firstly,bending deformation of these kinds of composite beam and panel was calculated through RZT.Then,using higher order deformation beam theorem to predict stress distribution of beam.At last,the bending deformation of these kinds of composite beam and panel was analyzed by using ANSYS finite element software.Using the experimental data as basis reference,contrastive analysis the numerical theory results and the results of composite sandwich beam and panel of porous metal and epoxy resin which are calculated by ANSYS finite element software.The results indicated that the three kinds of data are in good agreement. |
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