• Title/Summary/Keyword: elliptical hole

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Dispersion and Nonlinear Properties of Elliptical Air Hole Photonic Crystal Fiber

  • Rao, MP Srinivasa;Singh, Vivek
    • Current Optics and Photonics
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    • v.2 no.6
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    • pp.525-531
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    • 2018
  • The effect of eccentricity on dispersion and nonlinear properties of a photonic crystal fiber having elliptical air holes is investigated using a fully vectorial effective index method. It is found that the effective refractive index increases with increase of eccentricity. The dependence of dispersion and nonlinear properties of the PCF on the eccentricity of the air hole is investigated. It is revealed that eccentricity of the air hole affects the zero dispersion wavelength. Further, the nonlinear properties such as mode field area, nonlinear coefficient and self phase modulation of the Photonic crystal fibers are analyzed. The mode field area increases and the nonlinear coefficient decreases with increase in eccentricity. The variation of the self phase modulation with elliptical air hole is also discussed.

The Analysis of Fatigue Quality Index for Shape of Elliptical Hole in Plate (평판에서 타원공의 형상에 따른 피로도지수 해석)

  • 송준혁;노홍길;강희용;양성모
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2003.04a
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    • pp.130-136
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    • 2003
  • A FQI(fatigue quality index) analysis using the concept of SF(severity factor) is performed to various shape of elliptical hole. FQI is fatigue quality index to estimate the dynamic SF from static SF by finite element analysis. Since the SF is affected by the location of cutout in plate and radius ratio, static SF is analyzed with finite element method and forms the equation of FQI for predicting a dynamic SF. To examine the validity, dynamic SF is measured by photoelastics and thermalelastics for an epoxy resin plate with various elliptical holes under dynamic load.

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Novel design of higly-birefringet fiber with elliptical hollow (타원형 공동을 갖는 새로운 고복굴절 광섬유의 설계)

  • Hwang, In-Gak;Lee, Yong-Hui;O, Gyeong-Hwan;Payne, David N.
    • Proceedings of the Optical Society of Korea Conference
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    • 2004.02a
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    • pp.370-371
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    • 2004
  • We propose and analyze a novel high-birefringence fiber incorporating an elliptical air hole in the core. Compared to solid elliptical core fibers, several times higher birefringence is achieved with a sub-wavelength-sized hole.

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IRON LINE PROFILES FROM RELATIVISTIC ELLIPTICAL ACCRETION DISKS

  • CHANG HEON-YOUNG;CHOI CHUL-SUNG
    • Journal of The Korean Astronomical Society
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    • v.35 no.3
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    • pp.123-130
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    • 2002
  • An elliptical accretion disk may be formed by tidally disrupted debris of a flying-by star in an active galactic nucleus (AGN) or by tidal perturbation due to a companion in a binary black hole system. We investigate the iron K$\alpha$ line profiles expecting from a geometrically thin, relativistic, elliptical disk in terms of model parameters, and find that a broad and skewed line profile can be reproduced well. Its shape is variable to the model parameters, such as, the emissivity power-law index, the ellipticity of the disk, and the major axis orientation of the elliptical accretion disk. We suggest that our results may be useful to search for such an elliptical disk and consequently the tidal disruption event.

A Study on the Shape Optimal Design of Perforated Plate (다공평판의 형상최적화에 관한 연구)

  • 김형준;권영석;박정호;안찬우;김현수
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.10a
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    • pp.731-734
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    • 1997
  • In this study, a shape optimization is performed for circular and elliptical holes to reduce weight of a plate. It is accomplished in reference to the results of topology optimization of the square plate with circular hole. From the results. it is concluded that the stress values of shape optimization of them are satisfied with 100MPa of constraint condition.

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Experimental Study of the Effects of Nozzle Hole Geometry for di Diesel Engine (디젤엔진에서 노즐 홀 형상효과의 실험적 연구)

  • Ku, Kun-Woo;Lee, Young-Jin;Kim, In-Su;Lee, Choong-Won
    • Journal of ILASS-Korea
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    • v.12 no.3
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    • pp.154-159
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    • 2007
  • Spray tip penetration and spray angle for one main injection were measured at the atmospheric condition with the fuel injection pressure of 270 bar and 540 bar. It investigates an effect of different nozzle hole geometry of conventional cylindrical one and those of elliptical ones. Injection period represented by injector pulse drive was fixed at 1ms. From the result of this study, it is shown that spray tip penetration becomes shorter and spray angle becomes wider with the elliptical nozzle hole geometry due to fast break-up of a fuel liquid column.

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Stress Analysis of Composite Plate with an Elliptical Hole or a Crack Using Complex Potentials (복소퍼텐셜을 이용한 타원공 또는 균열을 가진 복합재 평판 응력해석)

  • Kwon, Jung-Ho;Hwang, Kyung-Jung
    • Composites Research
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    • v.20 no.5
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    • pp.56-63
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    • 2007
  • An approach using complex potentials is presented for analysis of composite plate with an elliptical hole or a rectilinear crack. Composite structure is susceptible to encounter impact damages, which lead to considerable decrease in its residual strength. Such impact damages could be modeled as an equivalent elliptical hole or notch-like crack. Even though finite element method is widely used to analyze stresses or fracture mechanics parameters around such damage, it is tedious to make successive FE-modeling for damage tolerance assessment under fatigue loadings. In this point of view, the solutions based on complex potentials are very simple and easy to use. The computed results are also compared and discussed with those from FEA.

Highly Birefringent Slotted-porous-core Photonic Crystal Fiber with Elliptical-hole Cladding for Terahertz Applications

  • Lee, Yong Soo;Kim, Soeun;Oh, Kyunghwan
    • Current Optics and Photonics
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    • v.6 no.2
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    • pp.129-136
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    • 2022
  • We propose a photonic crystal fiber (PCF) with a slotted porous core and elliptical-hole cladding, for high birefringence in the terahertz regime. Asymmetry in the guided mode is obtained mainly by using arrays of elliptical air holes in the TOPAS® polymer cladding. We investigate the tradeoff between several structural parameters and find optimized values that can have a high birefringence while satisfying the single-mode condition. The optical properties in the terahertz regime are thoroughly analyzed in numerical simulations, using a full-vector finite-element method with the perfectly-matched-layer condition. In an optimal design, the proposed photonic crystal fiber shows a high birefringence of 8.80 × 10-2 and an effective material loss of 0.07 cm-1 at a frequency of 1 THz, satisfying the single-mode-guidance condition at the same time. The proposed PCF would be useful for various polarization-management applications in the terahertz range.

Stress Intensity Factor Analysis of Elliptical Arc Through Cracks at Mechanical Fastener Holes by Weight Function Method ( I ) - Development of Weight Function Method - (가중함수법에 의한 기계적 체결홀에 존재하는 타원호형 관통균열의 음력확대계수 해석 ( I ) - 가중함수법의 전개 -)

  • Heo, Seong-Pil;Yang, Won-Ho;Hyeon, Cheol-Seung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.10
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    • pp.1659-1670
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    • 2001
  • It has been reported that cracks at mechanical fastener holes usually nucleate as elliptical corner cracks at the faying surface of the mechanical joints and grow as elliptical arc through cracks after penetrating the opposite surface. The weight function method is an efficient technique to calculate the stress intensity factors fur elliptical cracks using uncracked stress field. In this study the weight function method for three dimensional mixed-mode problem applied to elliptical comer cracks Is modified for elliptical arc through cracks and the stress intensity factors at two surface points of elliptical arc through cracks at mechanical fastener holes are analyzed by the weight function method. This study consists of two parts and in part I , the weight function method for elliptical arc through cracks is developed and verified.

Application of Weight Function Method to Elliptical Arc Through Cracks at Mechanical Fastener Holes (기계적 체결홀에 존재하는 타원호형 관통균열에 대한 가중함수법의 적용)

  • Heo, Sung-Pil;Yang, Won-Ho;Chung, Ki-Hyun;Hyun, Cheol-Seung
    • Proceedings of the KSME Conference
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    • 2001.11a
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    • pp.304-310
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    • 2001
  • Cracks at mechanical fastener holes usually nucleate as elliptical comer cracks at the faying surface of the mechanical joints and grow as elliptical arc through cracks after penetrating the opposite surface. In this study mode I, II and III stress intensity factors at two surface points of elliptical arc through cracks at mechanical fastener holes are analyzed by applying weight function method. The weight function method for two dimensional mixed-mode problem is extended to three dimensional one and it is verified.

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