• Title, Summary, Keyword: Complex Stress Function

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Stress analysis of creep material containing elliptical rigid inclusion by complex pseudo-stress function (복소 유사응력함수에 의한 타원 강체함유물을 내포하는 크립재료의 응력해석)

  • Lee, Kang-Yong;Kim, Jong-Sung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.22 no.2
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    • pp.408-415
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    • 1998
  • The analysis model is the power law creep material containing an elliptical rigid inclusion subjected to the arbitrarily directional stress on infinite boudary. The stress analysis is performed using the conformal mapping function and complex pseudo-stress function. The stress distributions near an elliptical rigid inclusion are obtained with various ellipse shapes, strain hardening exponents and directions of applied stress.

복소 유사 응력 함수에 의한 타원 강체 함유물을 내포하는 글잎 재료의 응력 해석

  • 김종성;이강용
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.740-743
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    • 1995
  • The analysis model is the power law creep material containing an elliptical rigid inclusion subjected to the arbitrarily directional stress on infinite boundary. The stress analysis is performed using the conformal mapping function and complex pseudo-stress function. The stress distributions near an elliptical rigid inclusion are obtained with various ellipse shapes, strain hardening exponents and directions of applied stress.

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Weight Function Theory for Piezoelectric Materials with a Crack (균열을 가진 압전재료에서의 가중함수이론)

  • 손인호;안득만
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.7
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    • pp.208-216
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    • 2003
  • In this paper, a two-dimensional electroelastic analysis is performed on a piezoelectric material with an open crack. The approach of Lekhnitskii's complex potential functions is used in the derivation and Bueckner's weight function theory is extended to piezoelectric materials. The stress intensity factors and the electric displacement intensity factor are calculated by the weight function theory.

Efficient methods for integrating weight function: a comparative analysis

  • Dubey, Gaurav;Kumar, Shailendra
    • Structural Engineering and Mechanics
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    • v.55 no.4
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    • pp.885-900
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    • 2015
  • This paper introduces Romberg-Richardson's method as one of the numerical integration tools for computation of stress intensity factor in a pre-cracked specimen subjected to a complex stress field across the crack faces. Also, the computation of stress intensity factor for various stress fields using existing three methods: average stress over interval method, piecewise linear stress method, piecewise quadratic method are modified by using Richardson extrapolation method. The direct integration method is used as reference for constant and linear stress distribution across the crack faces while Gauss-Chebyshev method is used as reference for nonlinear distribution of stress across the crack faces in order to obtain the stress intensity factor. It is found that modified methods (average stress over intervals-Richardson method, piecewise linear stress-Richardson method, piecewise quadratic-Richardson method) yield more accurate results after a few numbers of iterations than those obtained using these methods in their original form. Romberg-Richardson's method is proven to be more efficient and accurate than Gauss-Chebyshev method for complex stress field.

Residual fatigue life evaluation method for the cracked components under complex stress fields (복합응력장 하의 균열부재에 대한 잔류피로수명 평가방법)

  • Cho, Chang-Hee;Kim, sang-Tae;Kwon, Jae-Do
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.22 no.2
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    • pp.258-267
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    • 1998
  • This study reviews the influence function method(IFM) for calculating stress intensity factors (SIFs, K) and modifies it to apply for the estimating the residual fatigue life for the cracked components under complex stress fields. An IFM has been developed to analyze SIFs for surface cracks which are subjectedto nonuniformly distributed stresses. Through elastic superposition, the influence function method properly accounts for redistribution of stress as the crack grows through the component. This influence function is unique to the given geometry and independent of the loading. Some examples have been provided to show the effectiveness of the IFM including the distributions of K in a residual stress field. The significant effect of residual stress upon fatigue crack growth in a welded component has been demonstrated with the IFM.

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
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    • v.21 no.10
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    • pp.1702-1711
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    • 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.

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
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    • v.23 no.6
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    • pp.988-1000
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    • 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.

Weight Function Theory for Piezoelectric Materials with Crack in Anti-Plane Deformation (균열을 가진 압전재료에 대한 면외 변형에서의 가중함수이론)

  • Son, In-Ho;An, Deuk-Man
    • Journal of Ocean Engineering and Technology
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    • v.24 no.3
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    • pp.59-63
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    • 2010
  • In this paper, an electroelastic analysis is performed on a piezoelectric material with an open crack in anti-plane deformation. Bueckner’s weight function theory is extended to piezoelectric materials in anti-plane deformation. The stress intensity factors and electric displacement intensity factor are calculated by the weight function theory.

Reliability computation technique for ball bearing under the stress-strength model

  • Nayak, S.;Seal, B.
    • International Journal of Reliability and Applications
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    • v.17 no.1
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    • pp.51-63
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    • 2016
  • Stress function of ball bearing is function of multiple stochastic factors and this system is so complex that analytical expression for reliability is difficult to obtain. To address this pressing problem, in this article, we have made an attempt to approximate system reliability of this important item based on reliability bounds under the stress strength setup. This article also provides level of error of this item. Numerical analysis has been adopted to show the closeness between the upper and lower bounds of this item.

Crack Analysis of Creep Material Containing Rigid Inclusion with Line Crack Shape (직선 균열 강체 함유물을 내포하는 크?재료의 균열 해석)

  • 이강용;김종성
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.7
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    • pp.91-97
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    • 1998
  • The analysis model is the infinite body consisted of power law creep material containing a rigid inclusion with line crack shape subjected to the arbitrarily directional stress on an infinite boundary. The crack analysis is performed using the complex pseudo-stress function. The strain rate intensity factor is determined in the closed form as new fracture mechanics parmeter which represents the magnitudes of stress and strain rate near the tip in power law creep material.

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