Research On Vacuum Infiltration And Hot-Pressed Shape Memory Composite Material And Its Performance

With the development of aerospace,electronic communication and other fields,the demand for materials has gradually developed in the direction of structure-function integration.The traditional carbon fiber reinforced polymer(CFRP)has the advantages of light weight and high strength.It is a good structural load-bearing material,but its functionality is weak.By adding graphene,elastic curing agent,etc.to traditional CFRP components,a new type of CFRP material,namely graphene-carbon fiber(GR-CF)hybrid reinforced shape memory polymer matrix composite(SMPC),not only has the performance advantages of CFRP structure load-bearing,but also has the intelligent characteristics of shape memory and is a new type of material with both load-bearing and functional characteristics.This article focuses on the problems of the poor flexibility and adaptability in the existing preparation process of SMPC,the unclear flow behavior of the matrix solution in the fiber preform,the unclear mechanism of the effect of the coupling of multiple process parameters on the performance of the composite,and the imperfect method of optimizing process parameters.This article mainly carried out the following research:(1)By comparing and analyzing the advantages and disadvantages of the existing RTM molding process,autoclave molding process,compression molding process and other common carbon fiber composite materials preparation process advantages and disadvantages,this article innovatively proposed the vacuum infiltration hot press molding process.And according to the process forming principle,the process system is modularized,analyzed,and designed,and constructed in kind.Finally,the process system can economically,efficiently,and stably prepared excellent CFRP composite materials and SMPC composite materials,which provided a new reference idea for the preparation of such composite materials.(2)From the perspectives of statics and dynamics,respectively,the infiltration flow behavior of the matrix solution in the two-dimensional carbon fiber preform was explored,and the critical infiltration pressure of the matrix solution in the two-dimensional carbon fiber preform was calculated.The calculated values of the static and dynamic models were0.115 MPa and 0.478 MPa,respectively.Based on the theoretical derivation results of the infiltration flow behavior of the matrix solution in the fiber preform,the analysis of the mechanism of the influence of the three preparation process parameters of extrusion force,curing temperature and curing time on the bending strength of CFRP was carried out.The relationship between process parameters-preparation defects-bending properties was clarified,which laid a foundation for the subsequent preparation of SMPC composites with both mechanical load-bearing properties and shape memory properties in terms of impregnation mechanism and process parameter selection.(3)In this paper,25 sets of experiments were designed by orthogonal experiment method to explore the effect of four process parameters such as curing temperature,extrusion force,curing time,vacuum degree on the mechanical properties and shape memory properties of GR-CF hybrid reinforced SMPC composites.The influence weights of four key preparation process parameters on composite material properties were determined by grey correlation analysis method,and support vector regression analysis was used to construct a process parameter-material performance nonlinear mapping prediction relationship model.The fitting prediction effect of this model can reach 99.98%.Finally,under the optimized parameter matching rule of curing temperature of 80?,extrusion force of 0.9MPa,curing time of 150 min,and vacuum degree of-0.09 MPa,the ideal GR-CF hybrid reinforced SMPC composite was prepared,which the shape fixation rate was 98.14%,the shape recovery rate was 95.37%,and the bending strength was 465.02 MPa.