Research On Optimization And Deformation Method Of Resin Matrix Composite Curing Process

Thermosetting resin-based composites have the characteristics of light weight,high strength,strong designability and easy integral molding.They are widely used in the fields of new energy.aerospace,medical equipment and automobile manufacturing.At present,the most common process technology used by major manufacturers to prepare advanced composites is the autoclave molding process,but no matter which molding process is used,the composite material will undergo a curing process,and this process plays a decisive role in the performance of the molded part.When the thermosetting resin-based composites is cured.there is a phenomenon of"temperature overshoot" inside the laminate(the curing reaction of the resin rapidly releases heat and accumulates inside the laminate,resulting in a high temperature in the middle of the laminate and low temperatures on both sides),and there is a temperature gradient and degree of curing Gradient affects the mechanical properties of the composites;during curing,the thickness direction of the laminate produces chemical shrinkage strain and thermal strain,which causes the composites with corners to spring back and deform when it leaves the mold,which affects the accuracy of the molded part.This paper takes thermosetting resin matrix composites as the research object,finds optimized methods to solve the mechanical properties of molded parts,and uses analytical solutions to solve the accuracy problems of U-type composites.Based on the numerical simulation technology of the finite element method,this paper establishes a simulation model of the curing process of the resin matrix composites,and uses the finite element software ABAQUS combined with the FORTRAN subroutine method to simulate the temperature history and curing degree history of the composites curing process.Aiming at the"temperature overshoot" phenomenon in the curing process of composites,this paper proposes a multi-objective optimization method to solve this problem.Starting from optimizing the curing process temperature curve,take r1,r2,T1,T2,and dt1(respectively the first heating rate,the second heating rate,the first holding temperature,the second holding temperature,and the first holding time)As a design variable,under given constraints,the total curing time,the maximum temperature difference and the maximum curing degree difference are used as the objective function to establish an approximate model of the design variables and the objective function,and use a multi-objective optimization algorithm to optimize the approximate model,While shortening the curing time,improve the uniformity of the temperature field and the curing degree field,and get a better curing process temperature curve.The uneven curing of composite materials will induce the appearance of residual stress.For composites with corners,spring-in deformation will occur when they are separated from the mold.This paper proposes an analytical solution model for predicting the spring-in of U-type composites to accurately predicting the rebound angle of the U-type composites after it is cured and demolded provides a theoretical basis for studying the curing deformation of composites.The accuracy of the model is good after experimental verification.At the same time,the internal factors of the composites(parameters,equivalent elastic modulus E?,thermal expansion coefficient,resin chemical shrinkage rate)and structural parameters(thickness,corner radius,corner angle,web length,edge strip length)are analyzed for U-type composites the impact of material Spring-in,The analysis results show that,except for the length of the web,which has no effect on the rebound angle of the U-shaped composite material,other parameters have different effects on the rebound angle of the U-shaped composite material.