• Title, Summary, Keyword: hole eccentricity

Search Result 26, Processing Time 0.046 seconds

Compensation of the Error due to Hole Eccentricity of Hole-drilling Method in Uniaxile Residual Stress Field Using Neural Network (신경망 기법을 이용한 1축 잔류응력장에서 구멍뚫기법의 구멍편심 오차 보정)

  • Kim, Cheol;Yang, Won-Ho;Cho, Myoung-Rae
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.26 no.12
    • /
    • pp.2475-2482
    • /
    • 2002
  • The measurement of residual stresses by the hole-drilling method has been commonly used to evaluate residual stresses in structural members. In this method, eccentricity can usually occur between the hole center and rosette gage center. In this study, the error due to the hole eccentricity is compensated using the neural network. The neural network has trained training examples of normalized eccentricity, eccentric direction and direction of maximum stress at eccentric case using backpropagation learning process. The trained neural network could compensated the error of measured residual stress in experiments with hole eccentricity. The proposed neural network is very useful for compensation of the error due to hole eccentricity in hole-drilling method.

Correction of Error due to Hole Eccentricity in Hole-drilling Method Using Neural Network (신경망 기법을 이용한 구멍뚫기법에서의 구멍 편심오차 보정)

  • Kim, Cheol;Yang, Won-Ho;Cho, Myoung-Rae;Heo, Sung-Pil
    • Proceedings of the KSME Conference
    • /
    • /
    • pp.412-418
    • /
    • 2001
  • The measurement of residual stresses by the hole-drilling method has been commonly used to evaluate residual stresses in structural members. In this method, eccentricity can usually occur between the hole center and rosette gage center. In this study, the error due to the hole eccentricity is corrected using the neural network. The neural network has trained training examples of normalized eccentricity, eccentric direction and direction of maximum stress at eccentric case using backpropagation learning process. The trained neural network could corrected the error of measured residual stress in experiments with hole eccentricity. The proposed neural network is very useful for correction of the error due to hole eccentricity in hole-drilling method.

  • PDF

Influence of the Hole Eccentricity in Residual Stresses Measurement by the Hole-drilling Method (구멍뚫기법에 의한 잔류응력 측정시 구멍 편심의 영향)

  • Kim, Cheol;Seok, Chang-Seong;Yang, Won-Ho
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.24 no.8
    • /
    • pp.2059-2064
    • /
    • 2000
  • The measurement of residual stresses by the hole-drilling method has been commonly used to evaluate residual stresses in structural members. In this method, one of the source of error is due to the misalignment between the drilling hole and strain gage center. This paper presents a finite element analysis of the influence of such misalignment for the uniaxial residual stress field. The stress error increases proportionally to hole eccentricity. The correction equations which easily obtain the residual stress taking account of the hole eccentricity are derived. The stress error due to the hole eccentricity decreases by approximately one percent using this equations.

Prediction for the Error of Hole Eccentricity in Hole-drilling Method Using Neural Network (신경회로망을 이용한 구멍뚫기법의 편심 오차 예측)

  • Kim, Cheol;Yang, Won-Ho;Chung, Ki-Hyun;Hyun, Cheol-Seung
    • Proceedings of the KSME Conference
    • /
    • /
    • pp.956-963
    • /
    • 2001
  • The measurement of residual stresses by the hole-drilling method has been commonly used to evaluate residual stresses in structural members. In this method, eccentricity can usually occur between the hole center and rosette gage center. In this study, the error due to the hole eccentricity is predicted using the artificial neural network. The neural network has trained training examples of stress ratio, normalized eccentricity, off-centered direction and stress error using backpropagation loaming process. The prediction results of the error using the trained neural network are good agreement with FE analyzed ones.

  • PDF

Dispersion and Nonlinear Properties of Elliptical Air Hole Photonic Crystal Fiber

  • Rao, MP Srinivasa;Singh, Vivek
    • Current Optics and Photonics
    • /
    • v.2 no.6
    • /
    • pp.525-531
    • /
    • 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.

Prediction for the Error due to Role Eccentricity in Hole-drilling Method Using Backpropagation Neural Network (역전파신경망을 이용한 구멍뚫기법의 편심 오차 예측)

  • Kim, Cheol;Yang, Won-Ho;Heo, Sung-Pil;Chung, Ki-Hyun
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.26 no.3
    • /
    • pp.436-444
    • /
    • 2002
  • The measurement of residual stresses by the hole-drilling method has been commonly used to evaluate residual stresses in structural members. In this method, eccentricity can usually occur between the hole center and rosette gage center. In this study, the error due to the hole eccentricity is predicted using the artificial neural network. The neural network has trained training examples of stress ratio, normalized eccentricity, off-centered direction and stress error using backpropagation learning process. The prediction results of the error using the trained neural network are good agreement with FE analyzed ones.

Prediction of Error due to Eccentricity of Hole in Hole-Drilling Method Using Neural Network

  • Kim, Cheol;Yang, Won-Ho
    • Journal of Mechanical Science and Technology
    • /
    • v.16 no.11
    • /
    • pp.1359-1366
    • /
    • 2002
  • The measurement of residual stresses by the hole-drilling method has been used to evaluate residual stresses in structural members. In this method, eccentricity can usually occur between the hole center and rosette gage center. In this study, we obtained the magnitude of the error due to eccentricity of a hole through the finite element analysis. To predict the magnitude of the error due to eccentricity of a hole in the biaxial residual stress field, it could be learned through the back propagation neural network. The prediction results of the error using the trained neural network showed good agreement with FE analyzed results.

AJM을 이용한 HDM에 의한 잔류응력 계측에 관한 연구 2

  • 최병길;박영조;이택순;전상윤
    • Journal of Welding and Joining
    • /
    • v.8 no.4
    • /
    • pp.76-82
    • /
    • 1990
  • Lots of research works have been done to improve the accuracy of the hole drilling method to measure residual stress by many investigators. In this study, first, size effect of specimen was analyzed based on the solution of hole in a strip under tension. If the ratio of hole diameter tothe strip width is less than 0.2, the stress distribution around hold may be given from the solution of hole in an infinite plate. Second, the residual stress above $0.6{\sigma}_y$(yield stress) may be measured less than the actual stress by 10-15 percent. Third, eccentricity of hole relative to the rosette center effects on the accuracy of residual stress measurements by 10 percent. The error due to eccentricity of hole can be corrected by the iteration method or the direct method.

  • PDF

The Distribution of Boundaty Stresses around the Lightening Hole in a Triangular Bracket. (Bracket의 Lightening Hole 주변(周邊)에서의 응력분포(應力分布))

  • Hyo-Chul,Kim
    • Bulletin of the Society of Naval Architects of Korea
    • /
    • v.3 no.1
    • /
    • pp.11-18
    • /
    • 1966
  • In a polarized light field, triangular plate bracket specimen of CR-39 with lightening hole were subjected to tension. The variables of the models used in the experiment were taken in the range of length-depth $ratio=0.583{\sim}1.715$, eccentricity of lightening hole from the geometrical center of $bracket=-1/4"{\sim}+1/4"$, and the lightening hole $diameter=1/2"{\sim}2"$. The isoclinics were drawn and from those the stress trajectories were constructed. Then the distributions of boundary stress around the lightening holes were determined from the isochromatic fringe pattern. The conclusions reached in this investigation are as follows: 1. Maximum stresses of the hole boundary are gradually increased when the diameter of the lightning hole increase. 2. Maximum stresses of the lightning hole boundary are decreased gradually when the eccentricity of the lightning hole from the geometrical center of the bracket to the farther side from the free end. 3. If the minimum distances from the free end of the brackets to the lightening hole boundaries are equal, the variation of the maximum stresses are in a small range for the change of lightening hole diameter and its location. 4. When the length-depth ratios are smaller than 0.8, the maximum stresses increase steeply. In the range of $0.8{\sim}1.2$ maximum stresses increase gradually and thereafter increase rapidly when the length-depth ratio of the bracket increase for the same diameter of a lightening hole.

  • PDF