• Title, Summary, Keyword: 등각사상 맵핑

Search Result 5, Processing Time 0.038 seconds

Hybrid Full-field Stress Analysis around a Circular Hole in a Tensile Loaded Plate using Conformal Mapping and Photoelastic Experiment (등각사상 맵핑 및 광탄성 실험법에 의한 원형구명 주위의 하이브리드 응력장 해석)

  • Baek, Tae-Hyun;Kim, Myung-Soo;Rhee, Ju-Hun
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.23 no.6
    • /
    • pp.988-1000
    • /
    • 1999
  • An experimental study is presented for the effect of number of terms of a pewee series type stress function on stress analysis around a hole in tensile loaded plate. The hybrid method coupling photoelastsic data inputs and complex variable formulations involving conformal mappings and analytical continuity is used to calculate tangential stress on the boundary of the hole in uniaxially loaded, finite width tensile plate. In order to measure isochromatic data accurately, actual photoelastic fringe patterns are two times multiplied and sharpened by digital image processing. For qualitative comparison, actual fringes are compared with calculated ones. For quantitative comparison, percentage errors and standard deviations with respect to percentage errors are caculated for all measured points by changing the number of terms of stress function. The experimental results indicate that stress concentration factors analyzed by the hybrid method are accurate within three percent compared with ones obtained by theoretical and finite element analysis.

Effect of element size in hybrid stress analysis around a hole in loaded orthotropic composites (직교이방성 재료의 구멍주위에 관한 하이브리드 응력해석시 요소크기의 효과)

  • Baek, Tae-Hyun
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.21 no.10
    • /
    • pp.1702-1711
    • /
    • 1997
  • A numerical study for the number of terms of a power series stress function and the effect of hybrid element size on stress analysis around a hole in loaded orthotropic composites is presented. The hybrid method coupling experimental and/or theoretical inputs and complex variable formulations involving conformal mappings and analytical continuity is used to calculate tangential stress on the boundary of the hole in uniaxially loaded, finite width glass epoxy tensile plate. The tests are done by rarying the number of terms, element size and nodal locations on the external boundary of the hybrid region. The numerical results indicate that the hybrid method is accurate and powerful in both experimental and numerical stress analysis.

Analysis of Photoelastic Stress Field Around Inclined Crack Tip by Using Hybrid Technique (하이브리드 기법에 의한 경사균열 팁 주위의 광탄성 응력장 해석)

  • Chen, Lei;Seo, Jin;Lee, Byung-Hee;Kim, Myung-Soo;Baek, Tae-Hyun
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.34 no.9
    • /
    • pp.1287-1292
    • /
    • 2010
  • In this paper, a hybrid technique is presented. First, the isochromatic fringe data of a given set of points are calculated by the finite element method and are used as input data in complex variable formulations. Then the numerical model of the specimen with a central inclined crack is transformed from the physical plane to the complex plane by conformal mapping. The stress field is analyzed and the mixed-mode stress intensity factors are calculated for this complex plane. The stress intensity factors are calculated by the finite element method as well as by a theoretical method and compared with each other. In order to conveniently compare these values with each other, both actual and regenerated photoelastic fringe patterns are multiplied by a factor of two and sharpened by digital image processing.

Stress Distribution in the Vicinity of a Crack Tip in a Plate under Tensile Load Using Displacement Data of Finite Element Method (유한요소 변위값을 이용한 인장하중 판재 균열선단 주위의 응력분포 해석)

  • Baek, Tae-Hyun
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.25 no.10
    • /
    • pp.84-91
    • /
    • 2008
  • Due to the complexity of the engineering problems, it is difficult to obtain directly the stress field around the crack tip by theoretical derivation. In the paper, the hybrid method is employed to calculate full-field stress around the crack tip in uni-axially leaded finite width tensile plate, using the displacement data of given points calculated by finite element method as input data. The method uses complex variable formulations involving conformal mappings and analytical continuity. In order to accurately compare calculated fringes with experimental ones, both actual and reconstructed photoelastic fringe patterns are two times multiplied and sharpened by digital image processing. Reconstructed fringes by hybrid method are quite comparable to actual fringes. The experimental results indicate that Mode I stress intensity factor analyzed by the hybrid method are accurate within a few percent compared with ones obtained by empirical equation and finite element analysis.

Analysis of Stress Distribution around a Central Crack Tip in a Tensile Plate Using Phase-Shifting Photoelasticity and a Power Series Stress Function (위상이동 광탄성법과 멱급수형 응력함수를 이용한 인장시편 중앙 균열선단 주위 응력장 해석)

  • Baek, Tae-Hyun
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.29 no.1
    • /
    • pp.1-9
    • /
    • 2009
  • This paper presents stress distribution around a central crack tip in a tensile plate using phase-shifting photoelasticity and a power series stress function. Isochromatic data along the straight lines far from the crack tip were obtained by phase shifting photoelasticity and were used as input data of the hybrid experimental analysis. By using the complex-type power series stress equations, the photoelastic stress distribution fields in the vicinity of the crack and the mode I stress intensity factor were obtained. With the help of image processing software, accuracy and reliability was enhanced by twice multiplying and sharpening the measured isochromatics. Actual and reconstructed fringes were compared qualitatively. For quantitative comparison, percentage errors and standard deviations of the percentage errors were calculated for all measured input data by varying the number of terms in the stress function. The experimental results agreed with those predicted by finite element analysis and empirical equation within 2 percent error.