| As a new type of structural material,2.5D woven carbon fiber composite material has excellent in-plane and interlayer strength,high damage tolerance and impact resistance,which makes up for the poor interlaminar shear strength and toughness of traditional laminated composites.It has the disadvantages of easy impact delamination,and also has good profiling ability for shaped structural parts.It has been widely used in aerospace,defense military and biomedical engineering fields.In this paper,the mechanical properties and damage behavior of 2.5D woven carbon fiber composites are studied in order to better apply to the finite element modeling and simulation analysis of aero-engine stator blades,and improve the accuracy of finite element simulation analysis.The static mechanical properties of 2.5D woven carbon fiber composites were studied by sample load test and finite element model analysis.In the sample load test study,2.5D woven carbon fiber composites were prepared by resin transfer molding(RTM)method.The tensile,compressive and shear properties of the samples were tested according to the relevant ASTM standards.The macroscopic mechanical properties.In the finite element model analysis,the finite element cell model of the yarn was established on the microscopic scale,and the related mechanical properties of the yarn were obtained.The ideal 2.5D woven structure model was established on the mesoscale and after forming.Mechanical model of 2.5D woven carbon fiber composite with interlayer slip,and the mechanical properties of the same fiber bundle are substituted into the above two finite element models,and the same damage criterion and stiffness reduction law are embedded to carry out progressive damage analysis.The stiffness and strength of the 2.5D shallow-cross-linking structure before and after deformation are revealed,and the damage evolution mechanism of the material under tensile,compressive and shear loads is revealed.On the basis of the above,the above two different material properties are imparted to the root,end and blade of the 2.5D woven carbon fiber composite stator blade,and then the fluid-solid coupling simulation of the stator blade is carried out under the working conditions.The stress distribution and displacement distribution of the stator blades under working conditions show that the maximum stress appears at the joint between the lower right corner of the leaf stalk and the blade body,which is 22.84 MPa,which is much less than the fracture strength of the 2.5D woven composite.The maximum displacement appears in In the middle of the blade body,it is 15.34 um,which is better than the maximum deformation index requirement of the blade.The above results indicate that the 2.5D woven carbon fiber composite material meets the requirements for the use of stator blades.2.5D woven carbon fiber composite stator blades were prepared by RTM process.Firstly,a set of stator blade RTM forming molds was designed and processed.The local simulation was carried out in the weaving process of the stator blades according to the simulation results of the working conditions.The preforming weaving process parameters were optimized by combining the shape and structure characteristics of the mold and stator blades.The problem of size matching in the mold clamping process was solved.Finally,the RTM process parameters were optimized,the surface porosity defects of the carbon fiber composite stator blades were solved,and the 2.5D machine meeting the size and surface quality requirements was successfully prepared.Weaving carbon fiber composite stator blades.The research results of this thesis have a good theoretical and practical guiding significance for the finite element modeling,simulation analysis and forming of 2.5D woven carbon fiber composite structural parts. |
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