• Title/Summary/Keyword: Stress singularity index

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Analysis of Stress Singularities on Interfaces of Friction Welded Dissimilar Materials (마찰용접에 의한 이종재 접합계면에 대한 응력특이성의 해석)

  • Chung, Nam-Yong;Park, Chul-Hee
    • Transactions of the Korean Society of Automotive Engineers
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    • v.13 no.2
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    • pp.142-148
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    • 2005
  • In this paper, the stress singularity on interface of friction welded dissimilar materials was investigated by using 2-dimensional elastic boundary element method. It is required that stress distributions and stress singularities on an interface for friction welded dissimilar materials analize to establish strength evaluation. The stress singularity index ($\lambda$) and stress singularity factor ($\Gamma$) were calculated from the results of stress analysis. The stress singularities on variations for shapes and thickness of friction welded flashes were analized and discussed. This paper suggested that the strength evalution by using the stress singularity factors as fracture parameters, considering the stress singularity on an interface edge of friction welded dissimilar materials were very useful.

Analysis of Stress Singularity for the Excess Adhesive of Interface in Adhesively Bonded Joint (접착이음의 계면덧살에 대한 응력특이성 해석)

  • Chung, Nam-Yong;Park, Cheol-Hee
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.21 no.3
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    • pp.439-445
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    • 2012
  • The stress singularity for the excess adhesive on interface of adhesively bonded joint was investigated by using the 2-dimensional elastic boundary element method (BEM). To establish a reasonable strength evaluation method and a fracture criterion for the excess adhesive of interface in adhesively bonded joint, it is necessary to evaluate fracture parameters with various bonding conditions. Under the variations of adhesively bonded thickness (h) and diameter (d) for the excess adhesive, a stress analysis was performed, and from the results, the stress singularity index (${\lambda}$) and the stress singularity factor (${\Gamma}$) were calculated. The variations have a great influences on the stress singularity for the excess adhesive of interface in adhesively bonded joint, and the ${\Gamma}$ is reduced as the "h" and "d" increase.

Analysis of Residual Stress Singularities on Interfaces of Friction Welded SUH35/SUH3 (SUH35/SUH3 마찰용접 접합계면에 대한 잔류응력 특이성의 해석)

  • Chung, Nam-Yong;Park, Chul-Hee
    • Transactions of the Korean Society of Automotive Engineers
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    • v.13 no.5
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    • pp.104-111
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    • 2005
  • With increasing use of SUH35/SUH3 dissimilar materials for automotive engine valves, it is required that stress singularities under residual stress on an interface for friction welded dissimilar materials analyzed to establish strength evaluation. The stress singularity $index{\lambda}$ and stress singularities $factor{\Gamma}$ were calculated from using the results of stress analysis to consider residual stress and loads. The stress singularities on variations for shapes and thickness of welded flashes were analyzed and discussed. This paper suggested that the strength evaluation by using the stress singularity factors as fracture parameters, considering the stress singularity on an interface edge of friction welded dissimilar materials will be useful.

Strength Evaluation of Bonded Dissimilar Materials by Using Stress Singularity Factor (응력특이성계수에 의한 이종 접합재료의 강도평가)

  • Jeong, Nam-Yong;O, Bong-Taek
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.7
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    • pp.2087-2096
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    • 1996
  • Recentrly advantages in composite and light weight material techniques have led to the increased use of bonded dissimilar materials such as ceramics/metal bonded joints, IC package, brazing, coating and soldering in the various industries. It is required to analyze the evaluation method of fracture strength and design methodology of bonded joints in dissimilar materials. Stress singularity according to changes of scarf angles for bonded scarf joints in dissimilar materials was investigated by the boundary element method and static experiments. In this paper, effect of the stress singularity factors at the interface edges of scarf joints on various dissmilar materials combinations were investigated by analysis of its stress and stress singularity index using 2-dimensional elastic program of boundary element method. And the variations of stress singularity index by changes for Young's modulus ratios of materials and scarf angles were investigated. Also, it is found that stress singularities at bonded interface edges are disappeared for certain combination of scarf angle in a pair of bonded dissimilar materials. As the results, it is proposed that the strength evaluation by using stress singularity factors, $\Gamma$, considering stress singularity at the interface edges of bonded dissimilar materials, is very useful.

Analysis of Stress Singularity on Ceramics/Metal Bonded Joints (세라믹/금속 접합재에 대한 응력특이성의 해석)

  • Kim, Ki-Seong;Kim, Hui-Song;Chung, Nam-Yong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.10
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    • pp.3058-3067
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    • 1996
  • With increasing use of ceramics/metal bonded joints, It is required to analyze the residual stress distribution and stress singularity at an interface edge for its bonded joints. In this paper, the residual stress distribution and stress singularity index of the ceramics/metal bonded joints were analyzed by using 2-dimensional elastic boundary element method. The variations of residual stress distribution and stress singularity index are studied with changes for the combinations of ceramics/metal bodned joints.

Prediction of Crack Propagation Path Using Boundary Element Method in IC Packages (반도체 패키지의 경계요소법에 의한 균열진전경로의 예측)

  • Chung, Nam-Yong
    • Transactions of the Korean Society of Automotive Engineers
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    • v.16 no.3
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    • pp.15-22
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    • 2008
  • Applications of bonded dissimilar materials such as integrated circuit(IC) packages, ceramics/metal and resin/metal bonded joints, are very increasing in various industry fields. It is very important to analyze the thermal stress and stress singularity at interface edge in bonded joints of dissimilar materials. In order to investigate the IC package crack propagating from the edge of die pad and resin, the fracture parameters of bonded dissimilar materials and material properties are obtained. In this paper, the thermal stress and its singularity index for the IC package were analyzed using 2-dimensional elastic boundary element method(BEM). From these results, crack propagation direction and path by thermal stress in the IC package were numerically simulated with boundary element method.

Prediction of crack propagation path in IC package by BEM (경계요소법에 의한 반도체 패키지의 균열진전경로 예측)

  • Song, Chun-Ho;Chung, Nam-Yong
    • Proceedings of the KSME Conference
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    • 2001.06a
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    • pp.286-291
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    • 2001
  • Applications of bonded dissimilar materials such as IC package, ceramic/metal and resin/metal bonded joints, are very increasing in various industry fields. It is very important to analyze the thermal stress and stress singularity at interface edges in bonded joints of dissimilar materials. In orer to understand the package crack emanating from the edge of Die pad and Resin, fracture mechanics of bonded dissimilar materials and material properties are obtained. In this paper, the thermal stress and its singularity index for the IC package were analyzed using 2-dimensional elastic boundary element method. Crack propagation angle and path by thermal stress were numerically simulated with boundary element method.

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