• 제목/요약/키워드: submerged cylindrical shell

검색결과 25건 처리시간 0.025초

Design of intelligent estimation of composite fluid-filled shell for three layered active control structure

  • Ghamkhar, Madiha;Hussain, Muzamal;Khadimallah, Mohamed A.;Ayed, Hamdi;Naz, Muhammad Yasin;Tounsi, Abdelouahed
    • Computers and Concrete
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    • 제29권2호
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    • pp.117-126
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    • 2022

  • The vibrational characteristic of three-layered cylindrical shell (CS) submerged in fluid with the ring support has been studied. The inner and outer layer is supposed to construct by isotropic layer. The composition of central layer is of functionally graded material type. Acoustic Wave condition has been utilized to present the impact of fluid. The central layer of cylindrical shell (CS) varies by volume fraction law that has been expressed in terms of polynomial. The main shell frequency equation has been obtained by theory of Love's shell and Rayleigh-Ritz technique. The oscillation of natural frequency has been examined under a variety of end conditions. The dependence of axial model has been executed with the help of characteristic beam function. The natural frequencies (NFs) of functionally graded material (FGM) shell have been observed of cylindrical shell along the shell axial direction. Different physical parameters has been used to examine the vibration characteristics due to the effect of volume fraction law. MATLAB software has been used to get result.

  • https://doi.org/10.12989/cac.2022.29.2.117 인용 KSCI

전달함수법을 이용한 SWATH선의 수중 음향 방사 해석 (Analysis of Underwater Acoustic Radiation of SWATH vessel using Transfer Function Method)

  • 김재호
    • 한국군사과학기술학회지
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    • 제6권2호
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    • pp.20-34
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    • 2003

  • The good sea-keeping capability of the SWATH(Small Waterplane Area Twin Hull) ship has been attractive for research or surveillance vessels. Especially, for the naval ships accomplishing the underwater acoustic missions, it is necessary to access and minimize the underwater radiated noise level generated by the ships. Therefore, acoustic signature management and control are very important topics for these vessels. Underwater radiation pattern in the low frequency range is dominated by the tonals from the vibration of onboard machinery. In this work, the radiated noise level generated by the propulsion machine in the submerged hull is predicted using the transfer function technique and the hull transfer function for the submerged hull is determined by analyzing the longitudinal/circumferential stiffened infinitely long cylindrical shell and considering the empirical database of the previous vessels. It is confirmed that the transfer function technique can give useful information for identifying the noise source and estimating its contribution to the total radiatied noise level.

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유체에 잠긴 원통형 실린더의 파동 분산 특성 (Dispersion Characteristics of Cylindrical Shells Submerged in the Fluid)

  • 정병규;홍진숙;유정수;정의봉;신구균
    • 한국소음진동공학회논문집
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    • 제25권8호
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    • pp.575-582
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    • 2015

  • This paper deals with the dispersion relation of the waves sustained in a cylindrical shell submerged in the fluid. The waveguide finite method and the boundary element method are used to predict the dispersion characteristic of the cylindrical shell. The dispersion diagram of the cylinder is estimated from the eigenvalue problem and the forced vibration response. It follows that the water-loading leads to the decrease of the cut-on frequencies and the phase speeds of the bending waves. On the contrary, the longitudinal waves and the torsional waves are hardly affected by the fluid, and therefore the order of the cut-on frequencies of the waves is changed. The acoustic dispersion diagram is also estimated from the forced acoustic response to identify the characteristics of the wave radiated to the fluid. It follows that the acoustic waves on and near the surface of the cylinder are the same as those in the structure. But at the far field the acoustic waves caused by subsonic waves e.g., the bending waves disappear as the increase of the distance. Conclusively, the characteristics of waves in cylindrical shells are significantly affected by water-loading in terms of the cut-on frequency, the wave speed, the order of the cut-on and radiation.

  • https://doi.org/10.5050/KSNVE.2015.25.8.575 인용 PDF KSCI KPUBS HTML

움직이는 소스와 구형쉘의 상호작용 해석 (Transient interactions between submerged elastic shells and acoustic shock waves from a moving source)

  • 이민형;이범헌;이승엽
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2001년도 춘계학술대회논문집
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    • pp.85-89
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    • 2001

  • The problem of the transient interaction of a plane acoustic shock wave which has an infinitely steep wave front with a cylindrical or spherical elastic shell has been studied analytically from early fifties based on the integral transform and series solution techniques. Huang adopted an inverse Laplace transform, and used a finite number of terms of the infinite series expansion of the equations for the shells. In the 1990s, the results have been used by many authors for validation of computer codes. The object of this paper is to discuss the interaction between a moving source and submerged spherical shells. Since the center of source is moving the first contact location between the waves and shell changes depending on the source velocity and distance. These are considered in the analysis. Furthermore, constant source strength and decreasing strength are considered in the analysis. Radial velocities at several locations on the structure are obtained and the results are discussed.

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