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Acta Aeronautica et Astronautica Sinica ›› 2025, Vol. 46 ›› Issue (7): 430878.doi: 10.7527/S1000-6893.2024.30878

• Material Engineering and Mechanical Manufacturing • Previous Articles    

Multi-scale study of radial stiffness characteristics of plain C/C composite finger seals

Danlong SONG1,2(), Yuanhao WANG1, Keyi HUA1, Chunhua DU1, Yanchao ZHANG1, Yunjuan JING2   

  1. 1.School of Mechanical and Precision Instrument Engineering,Xi’an University of Technology,Xi’an 710048,China
    2.Shaanxi Yuanfeng Textile Technology Research Co. ,Ltd. ,Xi’an 710038,China
  • Received:2024-06-27 Revised:2024-07-15 Accepted:2024-08-05 Online:2024-08-13 Published:2024-08-10
  • Contact: Danlong SONG E-mail:songdanlong@xaut.edu.cn
  • Supported by:
    National Natural Science Foundation of China(51805429)

Abstract:

Carbon fiber reinforced carbon matrix (C/C) composite have unique excellent characteristics such as self-lubrication and wear resistance, making them well-suited to the technical requirements of dynamic seals and their corresponding application environments. These characteristics can significantly improve the service life of finger seals. However, the anisotropy performance, heterogeneous micro-structure and the complex curve lead to the complex mechanical characteristics of C/C composite finger beams, which further affects the sealing performance and service life of finger seals. Therefore,a multi-scale finite element model of the C/C composite finger seals was firstly constructed by analyzing the multi-scale structures and performance of the plain woven C/C composite laminates. Secondly, the variation trend and circumferential distribution characteristics of radial static stiffness of C/C composite finger beams with different positions and number of layers were analyzed deeply by the multi-scale finite element method. Finally, a radial mechanical performance test platform of the finger beam was built, and radial static stiffness of C/C composite finger beams with different angular positions was verified by experiments. The research results show that the load of circular finger beam increased linearly with the radial displacement, and its radial stiffness kept constant. The radial stiffness of the finger beam with three layers of carbon fiber fabric was about 3 times that of the finger beam with single layer. The radial stiffness of circumferential distributed finger beams presents a periodic distribution characteristic of decreasing first and then increasing, with a period of 90°, and the minimum stiffness was about 68% of the maximum stiffness. A large difference in radial stiffness will lead to local wear and hysteretic leakage. The research provides a reference and basis for the structure optimization and sealing performance of C/C composite finger seals.

Key words: finger seal, C/C composite, plain weave, multi-scale modeling, stiffness characteristic

CLC Number: