Analysis Of Solidification Deformation Of Composite Components And Optimization Of Mold Structure

The autoclave forming process is one of the widely used forming methods for advanced composite components for aviation.The basic principle is to provide the composite components with temperature and pressure conditions through the autoclave,complete the resin curing reaction,and make the composite material blank form into products that meet quality requirements.During the curing process of composite components,complex heat exchange and chemical reactions will occur,which will cause a solidification gradient inside the component,generate internal stress,and release the residual stress during the final demolding to cause the component to deform.In order to solve the above problems,this thesis uses a finite element numerical simulation analysis method,and uses ABAQUS and its subroutine HETVAL to introduce the curing kinetics into the heat conduction equation in the form of an internal heat source to establish the temperature field and curing degree of the composite component during the autoclave forming process.The three-dimensional finite element model of the field is used to study the distribution of temperature and curing degree in the autoclave forming of composite components.Based on this,combined with the finite element analysis theory of thermal deformation of laminates,the finite element prediction of the solidification deformation of composite members is made.Taking aircraft wing skin as an example,through the deformation experiments of composite members,which further verified the rationality and accuracy of the temperature field simulation model and the stress-strain analysis model.In addition,the forming mold,as an important auxiliary device for ensuring the external dimensions and positioning and assembly of the composite material components,has an important impact on the solidification and deformation of the components,mainly reflected in: first,the thermal expansion coefficient between the mold and the component is inconsistent;second,the interaction force between the mold and the component;third,the heat transfer between the mold and the component.Therefore,starting from the mold itself,this article focuses on the influence of mold material,thickness of the mold plate,and structural form on the solidification deformation of the component.The research shows that the larger the difference between the thermal expansion coefficient of the mold and the component,the greater the deformation of the component;the thicker the thickness of the mold plate,the worse the thermal conductivity,the greater the temperature difference in the thickness direction of the laminate,and the lower the center point temperature of the laminate,The longer the required curing completion time;the more uniform the temperature distribution of the surface of the template under different support structures,the smaller the component curing gradient.Based on the research on the influence of the mold on the forming of composite material components,this thesis mainly optimizes the mold structure from the two aspects of support structure and profile compensation.In terms of support structure,this thesis proposes a method for the optimal design of the mold support structure to achieve better curing synchronization of the components.An optimal design model of the mold support structure oriented to the temperature uniformity of the profile was established,and the optimal solution of the support structure was solved by orthogonal experiment method.By optimizing the design of the mold support structure,the maximum deformation of the component was reduced by 17.23%.In terms of profile compensation,this paper presents a method for profile compensation based on node deformation.It quantitatively compensates the amount of deformation of the component to the mold surface,and incorporates the solidified deformation of the component into the geometric design of the mold.The method achieves the purpose of controlling the deformation of the component,and the maximum deformation of the component is reduced by 78.77% after optimization.