• Title/Summary/Keyword: Pipe Structures

검색결과 461건 처리시간 0.024초

Burst capacity of pipe under corrosion defects and repaired with thermosetting liner

  • Akram, Ali;Mustaffa, Zahiraniza;Albarody, Thar M. Badri
    • Steel and Composite Structures
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    • 제35권2호
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    • pp.171-186
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    • 2020

  • This paper aims at providing insights on the use of thermosetting liner for the repair of offshore pipelines exposed to corrosion and leakage. The work which covers both experimental and numerical approaches were aspired due to the high cost of repair for pipelines, limitations of thermoplastic material and limited study of reinforced thermosetting liner. The experiment involves a destruction test called the burst test, carried out on an API 5L X42 carbon steel pipe under four case studies, namely (i) intact pipe, (ii) pipe with corrosion defect, (iii) pipe with corrosion defect and repaired with thermosetting liner and (iv) pipe with leakage and repaired with thermosetting liner. The numerical simulation was developed to first validate the experimental results and later to optimize the design of the thermosetting liner in terms of the number of layers required to restore the original strength of the pipe. The burst test shows an improvement in 23% of the burst capacity for the pipe with corrosion defects, after being repaired with a three-layer thermosetting liner. The parametric studies conducted showed that with an addition of thermosetting layers, the burst capacity improves by an average of 1.85 MPa. In conclusions, the improvement in strength can be further increased with increasing thickness of the thermosetting liner. The thermosetting liner was also determined to fail first inside the host pipe.

  • https://doi.org/10.12989/scs.2020.35.2.171 인용 KSCI

Nonlinear vibration of FG-CNTRC curved pipes with temperature-dependent properties

  • Mingjie Liu;Shaoping Bi;Sicheng Shao;Hadi Babaei
    • Steel and Composite Structures
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    • 제46권4호
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    • pp.553-563
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    • 2023

  • In the current research, the nonlinear free vibrations of curved pipes made of functionally graded (FG) carbon nanotube reinforced composite (CNTRC) materials are investigated. It is assumed that the FG-CNTRC curved pipe is supported on a three-parameter nonlinear elastic foundation and is subjected to a uniform temperature rise. Properties of the curved nanocomposite pipe are distributed across the radius of the pipe and are given by means of a refined rule of mixtures approach. It is also assumed that all thermomechanical properties of the nanocomposite pipe are temperature-dependent. The governing equations of the curved pipe are obtained using a higher order shear deformation theory, where the traction free boundary conditions are satisfied on the top and bottom surfaces of the pipe. The von Kármán type of geometrical non-linearity is included into the formulation to consider the large deflection in the curved nanocomposite pipe. For the case of nanocomposite curved pipes which are simply supported in flexure and axially immovable, the motion equations are solved using the two-step perturbation technique. The closed-form expressions are provided to obtain the small- and large-amplitude frequencies of FG-CNTRC curved pipes rested on a nonlinear elastic foundation in thermal environment. Numerical results are given to explore the effects of CNT distribution pattern, the CNT volume fraction, thermal environment, nonlinear foundation stiffness, and geometrical parameters on the fundamental linear and nonlinear frequencies of the curved nanocomposite pipe.

  • https://doi.org/10.12989/scs.2023.46.4.553 인용

On the computation of low-subsonic turbulent pipe flow noise with a hybrid LES/LPCE method

  • Hwang, Seungtae;Moon, Young J.
    • International Journal of Aeronautical and Space Sciences
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    • 제18권1호
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    • pp.48-55
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    • 2017

  • Aeroacoustic computation of a fully-developed turbulent pipe flow at $Re_{\tau}=175$ and M = 0.1 is conducted by LES/LPCE hybrid method. The generation and propagation of acoustic waves are computed by solving the linearized perturbed compressible equations (LPCE), with acoustic source DP(x,t)/Dt attained by the incompressible large eddy simulation (LES). The computed acoustic power spectral density is closely compared with the wall shear-stress dipole source of a turbulent channel flow at $Re_{\tau}=175$. A constant decaying rate of the acoustic power spectrum, $f^{-8/5}$ is found to be related to the turbulent bursts of the correlated longitudinal structures such as hairpin vortex and their merged structures (or hairpin packets). The power spectra of the streamwise velocity fluctuations across the turbulent boundary layer indicate that the most intensive noise at ${\omega}^+$ < 0.1 is produced in the buffer layer with fluctuations of the longitudinal structures ($k_zR$ < 1.5).

  • https://doi.org/10.5139/IJASS.2017.18.1.48 인용 PDF KSCI