• Title, Summary, Keyword: Adhesively Bonded Joints

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Evaluation Method of Bonded Strength Considering Stress Singularity in Adhesively Bonded Joints (응력특이성을 고려한 접착이음의 강도평가 방법)

  • 정남용
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.7 no.1
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    • pp.58-68
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    • 1998
  • Advantages of adhesively bonded joints and techniques of weight reduction have led to increasing use of structural adhesives such as LSI(large scale integration) package, automobile, aircraft in the various industries. In spite of such wide applications of adhesively bonded joints, the evaluation method of bonding strength has not been established. Stress singularity occurs at the interface edges of adhesively bonded joints and it is required to analyze it. In this paper, the stress singularity using 2-dimensional elastic boundary element method (BEM) with the changes of the lap length and adhesive for single lap joint was analyzed, and experiments of strength evaluation were carried out. As the results, the evaluating method of bonding strength considering stress singularity at interface edges of adhesively bonded joints and stress intensity factor of interface crack have been proposed in static and fatigue test.

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Fracture criterion of mixed mode in adhesively bonded joints of Al/Steel dissimilar materials (Al/Steel 이종재료의 접착이음에 대한 혼합모드의 파괴기준)

  • Jeong, Nam-Yong;Jang, Jin-Mo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.8
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    • pp.1322-1331
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    • 1997
  • A method of strength evaluation applying fracture mechanics in the adhesively bonded joints of Al/Steel dissimilar materials was investigated in this paper. Various shapes of adhesively bonded Al/Steel scarf joints focussing on fracture criterion of mixed mode crack were prepared for the static tests. Also, stress intensity factors of the interface cracks in adhesively bonded joints of Al/Steel dissimilar materials were analyzed with 2-dimensional elastic program of boundary element method(BEM), and the experiment of fracture toughness were carried out under various mixed mode conditions. From the results, the fracture criterion and method of strength evaluation by the fracture toughness in adhesively bonded joints of Al/Steel dissimilar materials were proposed.

Effect of the Cross Sectional Shapes on the Static and Fatigue Torque Transmission Capabilities of Adhesive Single Lap Joints (단면형상에 따른 단일겹치기 이음의 피로 및 정적 토크 전달특성에 관한 실험적 연구)

  • 최진경;이대길
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.4
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    • pp.835-845
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    • 1994
  • In this paper, the effects of the adhesive thickness and adherend roughness on the static and fatigue strengths of the adhesively bonded circular single lap joints has been investigated by an experimental method. The stacking sequence effect of the composite adherend on the static and fatigue strength and the fracture patterns of the adhesive failure were also observed. Since the circular single lap joint fails catastrophically beyond the static strength of fatigue limit, the tubular polygonal adhesively bonded joints such as triangular, tetragonal, pentagonal, hexagonal as well as elliptical joints were manufactured in order to give partial mechanical characteristics to the adhesively bonded tubular joints. These joints were tested both in static and fatigue modes. From the experimental investigations, it was found that the fatigue strength of the circular adhesively bonded joints was much dependent on the arithmetical average surface roughness of the adherends and the polygonal adhesively bonded joints had better fatigue strength characteristics than the circular adhesively bonded joints.

Prediction Fracture Strength on Adhesively Bonded scarf Joints in Dissimilar Materials (이종재료의 경사접착이음에 대한 파괴강도의 예측)

  • 정남용
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.4 no.4
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    • pp.50-60
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    • 1995
  • Recently advantages joining dissimiliar materials and light weight material techniques have led to increasing use of structural adhesives in the various industries. Stress singulartiy occurs at the interface edges of adhesively bonded dissimilar materials. So it is required to analyze its stress singularity at the interface edges of adhesively bonded joints indissimilar materials. In this paper, the analysis method of stress singularity is studied in detail. Also, effects of the stress singularity at the interface edge of adhesively bonded scarf joints in combinations of dissimilar materials are investigated by using 2-dimensional elastic program of boundary element method. As the results, the strength evaluation method of adhesively bonded dissimilar materials using the stress singularity factor, $\Gamma$,is very useful. The fracture criterion, method of strength evaluation and prediction of fracture strength by the stress singularity factor on the adhesively bonded dissimilar materials are proposed.

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Analyses of Stress Intensity Factors and Evaluation of Fracture Toughness in Adhesively Bonded DCB Joints (DCB 접착이음에 대한 응력세기계수의 해석 및 파괴인성의 평가)

  • Jeong, Nam-Yong;Lee, Myeong-Dae;Gang, Sam-Geun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.6
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    • pp.1547-1556
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    • 2000
  • In this paper, an evaluation method of fracture toughness to apply interfacial fracture mechanics was investigated in adhesively bonded double-cantilever beam (DCB) joints. Four types of adhesively bonded DCB joints with an interface crack were prepared for analyses of the stress intensity factors using boundary element method(BEM) and the fracture toughness test. From the results of BEM analysis and fracture toughness experiments, it is found that the stress intensity factor, K1 is a parameter driving the fracture of adhesively bonded joints. Also, the evaluation method of fracture toughness by separated stress intensity factors of mixed mode cracks was proposed and the influences of mode components for its fracture toughness are investigated in adhesively bonded DCB joints.

Mehods of Fracture Toughness and Evaluation for Interface Crack in Adhesively Bonded Joints (접착이음의 계면균열에 대한 파괴인성 및 평가방법)

  • 정남용
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.220-226
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    • 1998
  • In this pater, a method of strength evaluation applying fracture mechanics in adhesively bonded joints of A1/A1 materials was investigated. Various adhesively bonded joints of double-cantilever beam with a interfacial crack in its adhesive layer were prepared for the fracture toughness test of comprehensive mixed mode conditions from nearly pure mode I to mode II. The experiment of fracture toughness was carried out under various mixed mode conditions with an interfacial crack and critical energy release rate, Gc by the experimental measurements of compliances was determined. From the results, fracture toughness on mixed mode with an interfacial crack is well characterized by strain energy release rate and a method of strength evaluation by the fracture toughness in adhesively bonded joints of A1/A1 materials was discussed.

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Detection of Interface Crack Using Ultrasonic Method in Adhesively Bonded Joints (초음파 탐상법을 이용한 접착이음에 대한 계면균열의 검출)

  • Chung, Nam-Yong;Lee, Myung-Dae;Park, Sung-Il
    • Proceedings of the KSME Conference
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    • pp.97-102
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    • 2000
  • It is well recognized that the ultrasonic methods is one of the most common and reliable nondestructive testing(NDT) methods for the quantitative estimation of defects in welded structures. However, NDT techniques applying for adhesively bonded joints have not been clearly established yet. In this paper, the detection of interface crack by the ultrasonic method was applied for the measurement of interfacial crack length in the adhesively bonded joints of double-cantilever beam(DCB). The optimum condition of transmission coefficients in the adhesively bonded joints and it's experimental accuracy by the ultrasonic method have been investigated. The experimental values are in good agreement with the computed results by boundary element method(BEM) and Ripling's equation.

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ULTRASONIC DETECTION OF INTERFACE CRACK IN ADHESIVELY BONDED DCB JOINTS

  • Chung, N.-Y.;Park, S.-I.;Lee, M.-D.;Park, C.-H.
    • International Journal of Automotive Technology
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    • v.3 no.4
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    • pp.157-163
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    • 2002
  • It is well recognized that the ultrasonic method is one of the most common and reliable nondestructive testing (NDT) methods for the quantitative estimation of defects in welded structures. However, NDT techniques applying for adhesively bonded joints have not been clearly established yet. In this paper, the detection of interface crack by the ultrasonic method was applied for the measurement of interfacial crack length in the adhesively bonded joints of double-cantilever beam (DCB). An optimal condition of transmission coefficients and experimental accuracy by the ultrasonic method in the adhesively bonded joints have been investigated and discussed. The experimental values are in good agreement with the computed results by boundary element method (BEM) and Ripling's equation.

Evaluation of Fracture Toughness by Energy Release Rate for Interface Crack in Adhesively Bonded Joints (에너지 방출률에 의한 접착이음의 계면균열에 대한 파괴인성의 평가)

  • Jeong, Nam-Yong;Lee, Myeong-Dae;Gang, Sam-Geun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.9
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    • pp.2174-2183
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    • 2000
  • In this paper, the evaluation method of interfacial fracture toughness to apply the fracture toughness was investigated in adhesively bonded joints of AI/Ced./A1. Four types of adhesively bonded double-cantilever beam(DCB) joints with the interface crack were prepared for the test of interfacial fracture toughness. The experiments to measure the interfacial fracture toughness were performed under the various mixed-mode conditions. The critical energy release rate, Gc, was obtained by the experimental measurement of compliances. From the experimental results, the interfacial fracture toughness for the mixed-mode specimens is well characterized by the energy release rate, and the method of strength evaluation by the interfacial fracture toughness was discussed in adhesively bonded joints.

Detection of Interface Crack Using Ultrasonic Method in Adhesively Bonded Joints (초음파 탐상법을 이용한 접착이음에 대한 계면 균열의 검출)

  • Jeong, Nam-Yong;Park, Seong-Il;Lee, Myeong-Dae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.3
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    • pp.415-423
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    • 2001
  • In is well recognized that the ultrasonic method is one of the most common and reliable nondestructive testing(NDT) methods for the quantitative estimation of defects in welded structures. However, NDT techniques applying for adhesively bonded joints have not been clearly established yet. In this paper, the detection of interface crack by the ultrasonic method was applied for the measurement of interface crack length in the adhesively bonded joints of double-cantilever beam(DCB). The optimum condition of transmission coefficients and experimental accuracy by the ultrasonic method in the adhesively bonded joints have been investigated. The experimental values are in good agreement with the computed results by boundary element method(BEM) and Riplings equation.