Study And Prediction Of Mechanical Properties Of Carbon Fiber Reinforced Polyamide 6 Composites

Environmental problems and energy problems are two major problems in the world today.Automobiles not only consume a lot of energy,but also emit a lot of exhaust gas,which endangers the environment.Developing new energy and reducing the quality of automobiles can effectively solve energy and environmental problems.Composite material is a new type of material.It has the advantages of light weight and good mechanical properties,so it has been applied in automobiles.Carbon fiber reinforced thermoplastic composites have broad application prospects.Thermoplastic resin is easy to soften at high temperature,harden at low temperature,and there is no chemical reaction during this process.Even if the resin is heated and cooled several times,this property can still be maintained.Thermoplastic composites have strong plasticity,recyclability,convenient recycling,and almost no environmental pollution,which conforms to the development concept of environmental protection nowadays.In this paper,the mechanical properties and strength prediction of thermoplastic composite laminates with continuous high strength carbon fibers as reinforcing fibers and polyamide 6 as matrix were studied.Firstly,the basic theory of composite mechanics is expounded,the failure modes of composite materials under different loading conditions are discussed,and the analysis method of micro-mechanical strength of fiber reinforced composite materials is studied.Considering the influence of forming temperature and pressure on thermoplastic composites,carbon fiber reinforced polyamide 6(PA6)laminates with different fiber content and number of layers were prepared by hot pressing at fixed temperature and pressure.In order to ensure the size accuracy and surface quality of the test sample,CNC technology was used to process standard specimens.The tensile,compressive and shear mechanical properties of composite laminates were studied through mechanical experiments.The variation of strength with respect to fiber content and number of layers was analyzed.Finally,a strength prediction model considering the number of layers and the volume fraction of fibers was established based on the mixed law of the composite meso-model,and the results were compared with the experimental results.The results show that the tensile strength,compressive strength and shear strength of composites increase nonlinearly with the increase of fiber content,and the longitudinal tensile strength of composites is less affected by the change of fiber content when the fiber content is higher.With 37% fiber content,the longitudinal(along fiber direction)and transverse(vertical fiber direction)tensile strength of composites increased first and then decreased with the increase of the number of layers.When the number of layers is 5,the longitudinal tensile strength of the composite is the highest;when the number of layers is 6,the transverse tensile strength of the composite is the highest.The predicted value of the revised model is calculated by MATLAB,and the predicted value of the revised model is compared with the experimental value.It is found that the predicted results are in good agreement.