The Research On Dynamic Compressive Mechanical Properties Of Carbon Fiber Composites

Carbon fiber composites are widely used in aerospace, transportat ion and other fields due to the characterist ics of low specific gravit y, high specific strength and so on. This kind o f material is often subjected to the damage o f the impact o f external load in the process o f production and applicatio n. T herefore, it is necessary to do the research of the mechanical propert ies o f carbon fiber co mposites under the impact loading. At the same t ime, in the research o f impact response o f carbon fiber co mposites, because o f the rando mness of preparat ion process lead to material parameters uncertaint ies which can affect the performance o f t he material, so it must consider the effect o f uncertaint ies o f parameters to the impact response. In this paper, the method co mbines the experiment and numerical simulat ion to research the dynamic co mpressive mechanical propert ies of carbon fiber co mposit es considering uncertaint ies of parameters.First ly, in this paper, the experimental study on the response o f the carbon fiber co mposite specimens wit h different geo metrical sizes and layers under different impact loads is carried out. The dynamic compression experiments of carbon fiber co mposite specimens along the thickness direct ion are carried out by using the separating Split Hopkinson Pressure Bar(SHPB)and the influence of strain rate, thickness and stacking sequence on the impact resistance is studied. The results show that the material is strain rate sensit ive,and the seque nce and thickness of the layers both have an influence on the impact resistance o f carbon fiber co mposites, and the thickness is more significant than the stacking seque nce.Secondly, based on the experiment, numerical simulation o f impact response o f carbon fiber co mposites is carried out, and the mechanical propert ies o f the response are analyzed by numerical simulat ion. In this paper, the numerical model of impact response o f carbon fiber co mposites is established by using ABAQUS, the mechanical response of the carbon fiber co mposites under the effect o f shock load is simulated, and reliabilit y of the numerical model established in this paper is studied by co mparing numerical results with experimental results, and make a further studies o f the influence of the paving angle on the impact resistance of the material, the result s show that the impact resistance of the material is influenced by the paving angle significant ly.Thirdly, this paper researched the influence of parameters uncertainties to the impact response of carbon fiber co mposites, according to the sensit ive analysis o f material parameters o f this kind o f material; the sensit ivit y order of material parameters under different operat ing condit io ns is obtained, and researched effect o f the thickness o f the carbon fiber co mposite s, stacking and loading pressure on the parameter sensit ivit y sequence, the result s show that the loading pressure has almo st no influence on the sensit ivit y o f the material parameters, layer sequence and thickness have influence on the sensit ivit y of the material parameters, and the thickness is more remarkable than the stacking sequence.Finally, in order to ensure the real impact response of the material can be obtained by numerical calculat ion when the material parameters are changed, a numerical model validat ion method for the impact response o f carbon fiber co mposites with uncertain parameters is established, and the reliabilit y of the numerical model is verified by the limited experiments, co mbined wit h the model validat ion method. Through the research o f this chapter, it can provide a reliable guidance to the numerical study on the dynamic co mpressive mechanical propert ies o f carbon fiber co mposites under the condit ion of uncertain parameters uncertaint ies.