Analysis And Evaluation Of Typical Connection Scheme Of Stator Blade And Casing Of Different Materials

Compressor is the core component of aero engine, and compressor stator blade and the casing connection structure is compressor key components. The failure directly influence to the performance of aero engine. 2.5D braided composite material as a kind of three-dimensional braided composite material, effectively solves the problems of 3D braided composites in special fabric. Thus 2.5D braided composites are more widely used in complex structures in aircraft engine. At present the strength analysis method of connection scheme of braided composite stator blade and casing is not yet mature, and there is neither research experience for braided composites connecting with laminates or titanium alloy. This paper analyzes the strength of two programs of connections between 2.5Dbraided composite stator blade and casing, discusses the influence of yarn ratio on structure strength in connecting structures with enhance yarn, and predicts the structure strength of connecting structures using laminated composite material、titanium alloy and composite material. The main conclusions are as follows:(1) Research on the meso-structure model and stiffness prediction model of 2.5D braided composites. A 3-cell model of 2.5D braided composites is established, by the assumption of rectangle section for warp and hexagon section for weft and the consideration of the effect of RTM process on 2.5 dimensional braided composite layer warp. The stiffness prediction model is established based on the 3-cell model and the volume average method. A procedure of the stiffness prediction model is written by APDL language, and it is used to predict the mechanical properties of six different 2.5Dbraid composites. And compared with the existing experimental results to verify the effectiveness of the stiffness prediction model.(2) Different structure strength analysis methods are established according to different connection program between the stator blade and casing. Based on the idea of homogenization, the complex stator blade and casing connecting structure is divided into many cell size units. Given the material properties of different initial value of different materials according to different parts. Different failure criteria was used to judge the failure of single cell. Mechanical properties after degenerate is calculated by different stiffness degradation laws(except for metal). Different principles are used to judge the failure of the stator blade and the casing according to the failure position and the number of failure units. Evaluate the strength and tip deflection of 2 different connection programs using the same materials.(3) Predict the influence of yarn ratio on structure stiffness and strength in connecting structures with enhance yarn. Add straight enhance warp yarn to the weakest part of the connecting structure of the better connection program. Predict the range trend of mechanical properties of 2.5D braided composites while the yarn ratio increased from 0 to 1 using the stiffness prediction model of 2.5D braided composites with enhance yarn. And analyses the range trend of the tip deflection and strength of the connecting structure when the yarn ratio increased from 0 to 1.