• Title/Summary/Keyword: Adhesive Joints

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Fatigue Strength Evaluation of Adhesive Bonded and Mechanical Pressed Joints of Cold Rolled Steel Sheet (냉간압연강판 접착 및 기계적 프레스 접합부의 피로강도 평가)

  • Kim, Ho-Kyung
    • Journal of the Korean Society of Safety
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    • v.25 no.1
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    • pp.1-8
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    • 2010
  • The tensile and fatigue experiments were conducted with tensile-shear specimens for investigating the strength of adhesive bonded and mechanical press joints of SPCC steel sheet used in the field of the automobile industry. The optimal punch press force was evaluated 50kN for combining epoxy adhesive bonding and mechanical press joining with a diameter of 8.3mm using SPCC sheet with a thickness of 0.8mm. The combining epoxy adhesive bonding and mechanical press joining exhibits the maximum tensile force of 750N. The fatigue strengths of the combination of adhesive bond and mechanical press joint and pure adhesive joint were evaluated 370N and 320N at 106cycles, respectively. These values correspond to 22% and 20% of their maximum tensile forces, respectively. However, the fatigue strength of the combination of adhesive bond and mechanical press joining was much lower than that of pure mechanical press joining.

Experimental and numerical study on the failure of sandwich T-joints under pull-off loading

  • Nguyen, Khanh-Hung;Park, Yong-Bin;Kweon, Jin-Hwe;Choi, Jin-Ho;Shul, Chang-Won;Yang, Myung-Seog;Jun, Seung-Moon
    • International Journal of Aeronautical and Space Sciences
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    • v.13 no.2
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    • pp.229-237
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    • 2012
  • In this study, the failure mechanism of sandwich-to-laminate T-joints under pull-off loading was investigated by experiment and the finite element method. A total of 26 T-joint specimens were manufactured and tested in order to investigate the effects of both adhesive thickness (0.4, 2.0, and 4.0 mm) and environmental conditions on the failure of the joints. The results showed that failure occurred mainly as intralaminar failure in the first layer of the sandwich face, which was contacted to the paste adhesive. The failure load did not significantly change with increasing adhesive thickness in both RTD (Room Temperature and Dry) and ETW (Elevated Temperature and Wet) conditions. In the case of ETW conditions, however, the failure load increased slightly with an increase in adhesive thickness. The joints tested in ETW conditions had higher failure loads than those tested in RTD conditions. In addition to the experiment, a finite element analysis was also conducted to investigate the failure of the joint. The stress inside the first ply of the sandwich face was of interest because during the experiment, failure always occurred there. The analysis results showed good agreement with the trend of experimental results, except for the case of the smallest adhesive thickness. The highest stress was predicted in the regions where initial failure was observed in the experiment. The maximum stress was almost constant when the adhesive thickness was beyond 2 mm.

Improvement of Bonding Performance for Biotissue using Marine Mussel Extract Adhesive (홍합 추출 접착액을 이용한 바이오 티슈의 접합능력 향상에 관한 연구)

  • Cho, B.;Stroshine, Richard
    • Journal of Biosystems Engineering
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    • v.32 no.2 s.121
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    • pp.115-120
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    • 2007
  • The adhesive performance of marine mussel extract was compared with that of the commercial medical adhesives for fastening biotissue (SIS) bandages. Joints bonded with mussel extract showed stronger strength than those bonded with other commercial adhesives. The bonding strength was much improved when the moisture in the Joint was reduced using superporous hydrogel regardless of curing time under humid condition ($37^{\circ}C$ and 91% relative humidity). Water inflow into the SIS joint seemed to degrade the performance of mussel extracts adhesive especially for the joints of short period of curing time. The strength of SIS joints coated with surgical sealant was well maintained after being exposed to water inflow.

Humidity Aging Effect on Adhesive Strength of Composite Single-lap Joint

  • Kim, Myungjun;Kim, Yongha;Kim, Pyunghwa;Roh, Jin-Ho;Park, Jungsun
    • International Journal of Aeronautical and Space Sciences
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    • v.18 no.1
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    • pp.56-62
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    • 2017
  • Because adhesively bonded joints are used in many structural systems, it is important to predict accurate adhesive strengths. Composite aircraft with many joints are easily exposed to low temperatures and high relative humidity. This paper presents a humidity aging effect on the adhesive strength of a composite single-lap joint (SLJ). The adhesive strength of the SLJ is predicted using a finite element analysis with a cohesive zone model (CZM) technique. The humidity aging effect is evaluated based on the adhesive strength and CZM parameters. A lap joint test is carried out on the composite SLJ specimens, which are exposed for four months of 100% R.H. at $25^{\circ}C$. The predicted strengths are in good agreement with experimental data, and the actual crack propagation is satisfactorily simulated using the local CZM technique.

Analysis for Strength Estimation of Adhesive Joints (접착이음의 강도평가에 대한 해석)

  • 박성완;이장규
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2004.10a
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    • pp.98-107
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    • 2004
  • The objectives of this research are to establish the criteria of peel occurrence considering the shape of bond terminus and to compare the strength properties of some adhesive joints. The criteria of feel occurrence at the bond terminus was suggested. Peel loads of some adhesive joint(butt joint, T -shape specimen, single lap joint) were determined from tensile tests. Principal stress distributions of these joints were determined from finite element method analysis. Then, peel occurrence was estimated with intensity of stress singularity ' $K_{prin.}$' when the terminus shape was square, with average principal stress when the terminus shape was rounded. The conclusions are summarized as follows; (1) In the non-filleted model(e.g., butt joint, T-shape specimen), principal stress shows singularity at the bond terminus, intensity of stress(principal stress) singularity ' $K_{prin.}$&apso; can use as the criteria of peel occurrence at the bond terminus. (2) In the filleted model(e.g., single lap joint), principal stress doesn't show singularity at the bond terminus. Average principal stress can use as the criteria of peel occurrence at the bond terminus.'t show singularity at the bond terminus. Average principal stress can use as the criteria of peel occurrence at the bond terminus.

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Analysis for Strength Estimation of Adhesive Joints (접착이음의 강도평가에 대한 해석)

  • Park Sung-Oan
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.14 no.5
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    • pp.62-73
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    • 2005
  • The objects of this research are to establish the criteria of peel occurrence considering the shape of bond terminus and to compare the strength properties of adhesive joint of different three type such as butt joint, T-shape, and single lap Joints. The criteria of peel occurrence at the bond terminus was suggested. Peel loads of three type adhesive joint (butt Joint, T-shape specimen, single lap joint) were determined from tensile tests. Principal stress distributions of these joints were determined from finite element method analysis. Then, peel occurrence was estimated with stress singularity factor$(K_{prin})$ when the terminus shape was square, with average principal stress when the terminus shape was rounded. The conclusions are summarized as follows; (1) In the non-filleted model(e.g., butt joint, T-shape specimen), principal stress shows singularity at the bond terminus, intensity of stress(principal stress) singularity $(K_{prin})$ can use as the criteria of peel occurrence at the bond terminus. (2) In the filleted model(e.g., single lap joint), principal stress has not affected singularity at the bond terminus. Average principal stress$(K_{av})$ can use as the criteria of peel occurrence at the bond terminus.

Stress Analysis of Single-Lap Adhesive Joints Considering Uncertain Material Properties (물성치의 불확실성을 고려한 단일 겹치기 이음의 응력해석)

  • 김태욱
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.16 no.4
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    • pp.401-406
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    • 2003
  • This paper deals with stress analysis of single-lap adhesive joints which have uncertain material properties. Basically, material properties have a certain amount of scatter and such uncertainties can affect the performance of joints. In this paper, the convex modeling is introduced to consider such uncertainties in calculating peel and shear stress of adhesive joints and the results are compared with those from the Monte Carlo simulation. Numerical results show that stresses increase when uncertainties considered, which indicates that such uncertainties should not be ignored for estimation of structural safety. Also, the results obtained by the convex modeling and the Monte Carlo simulation show good agreement, which demonstrates the effectiveness of convex modeling.

A Study on Strength Evaluation of Adhesive Joints(1st Report, Stress Analysis and Fracture Strength of Adhesive Single-Lap Joint) (접착이음의 강도평가에 관한 연구 (제1보 겹치기 접착이음의 응력해석과 파괴강도))

  • 정남용
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.4
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    • pp.667-674
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    • 1992
  • Recently advantages in composite and light weight material technique have led to the increased use of structural adhesives in various industries. In spite of such wide application of the adhesive joints, the evaluation method of fracture strength and design methodology of them, have not been established. In this study finite element method, theoretical and experimental analyses were investigated according to changes of lap length and adhesive for adhesive single-lap joint. As the results, the strength evaluation of adhesive joint by conventional nominal stress, was pointed out inadequate strength evaluation and design method regardless stress singularity, stress distribution and crack propagation in its adhesive layer. Also, it was examined the problems to apply fracture mechanics by means of static and fatigue test.

Adheive Joining Technique for Composite/Aluminum Joint in Carbody of Tilting Train (틸팅차량 차체의 복합재/알루미늄 접합을 위한 접착체결기법)

  • Yoon Sung-Ho;Shin Kwang-Bok;Han Seong-Ho
    • Proceedings of the KSR Conference
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    • 2003.10c
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    • pp.395-400
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    • 2003
  • Adhesive joining technique is considered as one of hot issues in developing advanced composite structures. The designer should be familiar with important guidelines of fundamental principles and ideas underlying the design and application of adhesive joints for a correct joint design. This study deals with the following characteristics of adhesive joining techniques: (1) design parameters the affect the performance of joining, (2) fundamental principles and design methods of joining, (3) adhesive selection, (4) surface pre-treatment of the adherand, and (6) test methods. The results would be used to predict the performance of adhesive joints subjected to a thermal aging.

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Strength Evaluation of Adhesively Bonded Single-Lap Joints by Ultrasonic Signal Analysis (초음파신호해석을 이용한 단순겹치기 접착이음의 강도평가)

  • Oh Seung-Kyu;Jang Chul-Sub;Han Jun-Young;Lee Won
    • Journal of Welding and Joining
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    • v.22 no.5
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    • pp.32-37
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    • 2004
  • Application of bonding by adhesives can be found in many industries, particularly in advanced technological domains such as aeronautical and space, automobile and electronics industries. Periodic inspection with conventional ultrasonic NDE techniques is capable of indicating the presence and possible location of crack. Continuous ultrasonic attenuation monitoring has potential to supply information. This article discusses the use of pulse-echo ultrasonic testing for the inspection of adhesive bonds between metal sheets. The method is based on the measurement of the reflection coefficient at the metal/adhesive interface. By means of a control experiment it is shown that Quantitative Nondestructive Evaluation in Adhesive Joints are evaluated together with Ultrasonic Testing and Fracture Testing.