Journal of Aeronautical Engineering

Journal of Aeronautical Engineering

Analysis of the Strength of Autofrettaged Steel Pipes and Autofrettaged Composite Fiber-Reinforced Steel Pipes in Aerospace Structures

Document Type : Original Article

Authors
1 PhD Student, Faculty of Aerospace Engineering, Malek Ashtar University of Technology, Tehran, Iran
2 Assistant Professor, Faculty of Aerospace Engineering, Shahid Sattari University of Aeronautical Sciences and Technology, Tehran, Iran
Abstract
In industry and advanced technologies, the autofertigation method is recognized as an effective technique for increasing the strength and improving the fatigue life of pipes and vessels under internal pressure. This method significantly enhances their performance by generating residual compressive stresses inside the pipes. Due to the necessity of reducing weight in aerospace equipment, the use of complex fiber pipes has also been considered an innovative solution.The aim of this research is to investigate and analyze the combination of the autofertigation method and complex fibers to increase the strength of steel pipes under internal pressure. Initially, the equations related to steel pipes were extracted, followed by the derivation of equations pertaining to composite multilayer structures. These equations were then combined using a specialized algorithm. The innovation of this method lies in the integration of autofertigation and complex fibers. The research findings indicate that fiber angles in the range of 45 to 55 degrees are optimal for complex fibers. Furthermore, under identical pressure conditions, Autofrettaged fiber spiral tubes exhibit a significant advantage in terms of strength compared to Autofrettaged steel tubes without fibers. Additionally, studies reveal that boron epoxy is identified as a more suitable option than carbon epoxy in complex fibers. Ultimately, the decision between Autofrettaged tubes and composite tubes should be made by designers based on three key factors: weight reduction, increased compressive residual stresses within the tube, and decreased tensile residual stresses externally. These results can greatly assist in optimizing the design of aerospace structures and related industries.
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Volume 28, Issue 1
July 2026
Pages 1-15

  • Receive Date 02 December 2024
  • Revise Date 31 December 2024
  • Accept Date 16 January 2025