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Toshiyuki Sawa - One of the best experts on this subject based on the ideXlab platform.

  • effect of Adhesive Thickness Adhesive type and scarf angle on the mechanical properties of scarf Adhesive joints
    International Journal of Solids and Structures, 2013
    Co-Authors: Lijuan Liao, Chenguang Huang, Toshiyuki Sawa
    Abstract:

    The effects of Adhesive Thickness, Adhesive type and scarf angle, which are determined as the main control parameters by the dimensional analysis, on the mechanical properties of a scarf Adhesive joint (SJ) subjected to uniaxial tensile loading are examined using a mixed-mode cohesive zone model (CZM) with a bilinear shape to govern the interface separation. Particularly, the Adhesive-dependence of the vital cohesive parameters of CZM, which mainly include initial stiffness, total fracture energy and separation strength, is introduced emphatically. The numerical results demonstrate that the ultimate tensile loading increases as the Adhesive Thickness decreases. Cross the ultimate tension, the joint loses the load-bearing capacity when adopting the brittle Adhesive but sustains partial load-bearing capacity while selecting the ductile Adhesive. In addition, for the joint with the ductile Adhesive, the maximum applied displacement until the complete failure of it is directly proportional to the Adhesive Thickness, which is different from the case using the brittle Adhesive. Taking the combination of the ultimate loading and applied displacement into account, failure energy is employed to evaluate the joint performances. The results show that the failure energy of the joint with the brittle Adhesive increases as the Adhesive Thickness decreases. Conversely, the situation of the joint using the ductile Adhesive is vice versa. Moreover, the effect of the Adhesive Thickness becomes more noticeable with decreasing the scarf angle owing to the variation of the proportion of each component of the mixed-mode. Furthermore, all the characteristic parameters (the ultimate tensile loading, the maximum applied displacement and the failure energy) that adopted to describe the performances of SJ increase as the scarf angle decreases. Finally, the numerical method employed in this study is validated by comparing with existing experimental results. ? 2013 Elsevier Ltd. All rights reserved.

  • fem stress analysis and strength prediction of scarf Adhesive joints under static bending moments
    International Journal of Adhesion and Adhesives, 2013
    Co-Authors: Hiroko Nakano, Yasuhisa Sekiguchi, Toshiyuki Sawa
    Abstract:

    Abstract The stress distributions at the interfaces in the scarf Adhesive joints under static bending moments were analyzed using two-dimensional and three-dimensional finite element (FEM) calculations. The effects of the scarf angle, Adhesive Young's modulus and the Adhesive Thickness on the interface stress distribution were examined. It was found that the singular stress at the edges of the interfaces decreased as the Adhesive Young's modulus increased and the Adhesive Thickness decreased. The singular stress at the edges of the interfaces obtained from the 3-D was larger than that from the 2-D FEM. The joint strength was also predicted using the elasto-plastic 3-D FEM calculations. For verification of the FEM calculation results, the strains in the adherends and the joint strengths were measured. The measured results of the strains and the joint strengths were fairly consistent with the results obtained from the 3-D FEM calculations and indicated that the rupture bending moment (joint strength) was the maximum when the scarf angle was around 60°.

  • a three dimensional finite element stress analysis and strength evaluation of stepped lap Adhesive joints subjected to static tensile loadings
    International Journal of Adhesion and Adhesives, 2008
    Co-Authors: Kohei Ichikawa, Yuichiro Shin, Toshiyuki Sawa
    Abstract:

    Abstract Stress distributions in stepped-lap Adhesive joints subjected to static tensile loadings are analyzed using three-dimensional finite-element calculations. For establishing an optimum design method of the joints, the effects of the Adhesive Young's modulus, Adhesive Thickness and number of steps on the interface stress distributions are examined. The results show that the maximum value of the maximum principal stress σ 1 occurs at the edge of the Adhesive interfaces. The maximum value of the stress σ 1 decreases as the Adhesive Young's modulus and number of steps increase and as the Adhesive Thickness decreases under static loadings. A method for estimating the joint strength under static loadings is proposed using interface stress distributions. For verification of the finite-element method calculations, experiments were carried out to measure the strains and the joint strengths under static loadings. Fairly good agreements were found between the numerical and the experimental results.

  • a three dimensional finite element stress analysis and strength estimation of stepped lap Adhesive joints of similar adherends subjected to static tensile loadings
    Transactions of the Japan Society of Mechanical Engineers. A, 2007
    Co-Authors: Kohei Ichikawa, Yuichiro Shin, Toshiyuki Sawa
    Abstract:

    Stress distributions in stepped-lap Adhesive joints subjected to static tensile loadings are analyzed using a three-dimensional finite-element method (FEM). For establishing an optimum design method of the joints, the effects of Adhesive Young's modulus, the Adhesive Thickness and a number of steps on the interface stress distributions are examined. As the results, it is found that the maximum value of the maximum principal stress σ1 occurs at the butted edge of the Adhesive interfaces. The maximum value of σ1 decreases as the Adhesive Young's modulus and the number of steps increase, and as the Adhesive Thickness decrease. In addition, the difference in the stress distributions between the 2-D and 3-D FEM calculations was shown. A method for estimating the joint strength is proposed using the interface stress distributions. For verification of the FEM calculations, experiments were carried out to measure the strains of the adherends and the joint strengths. Fairly good agreements are found between the numerical and the experimental results.

Yu-yang Pang - One of the best experts on this subject based on the ideXlab platform.

  • theoretical and numerical study on stress intensity factors for frp strengthened steel plates with double edged cracks
    Sensors, 2018
    Co-Authors: Hai-tao Wang, Yu-yang Pang
    Abstract:

    This paper presents a theoretical and numerical study on the stress intensity factors for double-edged cracked steel plates strengthened with fiber reinforced polymer (FRP) plates. Based on the stress intensity factor solution for infinite center-cracked steel plates strengthened with FRP plates, expressions of the stress intensity factors were proposed for double-edged cracked steel plates strengthened with FRP plates by introducing two correction factors: β and f. A finite element (FE) simulation was carried out to calculate the stress intensity factors of the steel plate specimens. Numerous combinations of the specimen width, crack length, FRP Thickness and Young's modulus, Adhesive Thickness, and shear modulus were considered to conduct the parametric investigation. The FE results were used to investigate the main influencing factors of the stress intensity factors and the correction factor, β. The expression of the correction factor, β, was formulated and calibrated based on the FE results. The proposed expressions of the stress intensity factors were a function of the applied stress, the crack length, the ratio between the crack length and the width of the steel plate, the stiffness ratio between the FRP plate and steel plate, the Adhesive Thickness, and the shear modulus. Finally, the theoretical results and numerical results were compared to validate the proposed expressions.

  • Theoretical and Numerical Study on Stress Intensity Factors for FRP-Strengthened Steel Plates with Double-Edged Cracks
    MDPI AG, 2018
    Co-Authors: Hai-tao Wang, Yu-yang Pang
    Abstract:

    This paper presents a theoretical and numerical study on the stress intensity factors for double-edged cracked steel plates strengthened with fiber reinforced polymer (FRP) plates. Based on the stress intensity factor solution for infinite center-cracked steel plates strengthened with FRP plates, expressions of the stress intensity factors were proposed for double-edged cracked steel plates strengthened with FRP plates by introducing two correction factors: β and f. A finite element (FE) simulation was carried out to calculate the stress intensity factors of the steel plate specimens. Numerous combinations of the specimen width, crack length, FRP Thickness and Young’s modulus, Adhesive Thickness, and shear modulus were considered to conduct the parametric investigation. The FE results were used to investigate the main influencing factors of the stress intensity factors and the correction factor, β. The expression of the correction factor, β, was formulated and calibrated based on the FE results. The proposed expressions of the stress intensity factors were a function of the applied stress, the crack length, the ratio between the crack length and the width of the steel plate, the stiffness ratio between the FRP plate and steel plate, the Adhesive Thickness, and the shear modulus. Finally, the theoretical results and numerical results were compared to validate the proposed expressions

Hai-tao Wang - One of the best experts on this subject based on the ideXlab platform.

  • theoretical and numerical study on stress intensity factors for frp strengthened steel plates with double edged cracks
    Sensors, 2018
    Co-Authors: Hai-tao Wang, Yu-yang Pang
    Abstract:

    This paper presents a theoretical and numerical study on the stress intensity factors for double-edged cracked steel plates strengthened with fiber reinforced polymer (FRP) plates. Based on the stress intensity factor solution for infinite center-cracked steel plates strengthened with FRP plates, expressions of the stress intensity factors were proposed for double-edged cracked steel plates strengthened with FRP plates by introducing two correction factors: β and f. A finite element (FE) simulation was carried out to calculate the stress intensity factors of the steel plate specimens. Numerous combinations of the specimen width, crack length, FRP Thickness and Young's modulus, Adhesive Thickness, and shear modulus were considered to conduct the parametric investigation. The FE results were used to investigate the main influencing factors of the stress intensity factors and the correction factor, β. The expression of the correction factor, β, was formulated and calibrated based on the FE results. The proposed expressions of the stress intensity factors were a function of the applied stress, the crack length, the ratio between the crack length and the width of the steel plate, the stiffness ratio between the FRP plate and steel plate, the Adhesive Thickness, and the shear modulus. Finally, the theoretical results and numerical results were compared to validate the proposed expressions.

  • Theoretical and Numerical Study on Stress Intensity Factors for FRP-Strengthened Steel Plates with Double-Edged Cracks
    MDPI AG, 2018
    Co-Authors: Hai-tao Wang, Yu-yang Pang
    Abstract:

    This paper presents a theoretical and numerical study on the stress intensity factors for double-edged cracked steel plates strengthened with fiber reinforced polymer (FRP) plates. Based on the stress intensity factor solution for infinite center-cracked steel plates strengthened with FRP plates, expressions of the stress intensity factors were proposed for double-edged cracked steel plates strengthened with FRP plates by introducing two correction factors: β and f. A finite element (FE) simulation was carried out to calculate the stress intensity factors of the steel plate specimens. Numerous combinations of the specimen width, crack length, FRP Thickness and Young’s modulus, Adhesive Thickness, and shear modulus were considered to conduct the parametric investigation. The FE results were used to investigate the main influencing factors of the stress intensity factors and the correction factor, β. The expression of the correction factor, β, was formulated and calibrated based on the FE results. The proposed expressions of the stress intensity factors were a function of the applied stress, the crack length, the ratio between the crack length and the width of the steel plate, the stiffness ratio between the FRP plate and steel plate, the Adhesive Thickness, and the shear modulus. Finally, the theoretical results and numerical results were compared to validate the proposed expressions

Dai Gil Lee - One of the best experts on this subject based on the ideXlab platform.

  • optimum glass fiber volume fraction in the Adhesive for the al sus Adhesively bonded joints at cryogenic temperatures
    Composite Structures, 2014
    Co-Authors: Chang Seon Bang, Choongheum Park, Dai Gil Lee
    Abstract:

    Abstract The tight control of Adhesive Thickness in large bonding areas such as the secondary barrier of CCS (cargo containment system) for LNG (Liquefied Natural Gas) carriers or floaters is difficult and expensive although the Adhesive Thickness is a dominant parameter to determine the bonding performance of Adhesively bonded joint, especially at cryogenic temperatures. Therefore, the method for improving bonding strength and fracture toughness for thick Adhesive layer was investigated by reinforcing the Adhesive layer with glass fiber mat for the robust and sustainable system design for the secondary barrier. Randomly oriented E-glass fiber mat was used as reinforcement for the film type epoxy Adhesive. The lap shear strength and fracture behavior were investigated with respect to fiber volume fraction, and compared to those of the Adhesive without reinforcement. The effects of repeated thermal shocks on Adhesive bonding performances of Adhesive joints with reinforced Adhesive were also studied. The experimental results revealed that the randomly oriented glass fiber reinforcement improved much the bonding strength and fracture toughness of Adhesive even with 1.0 mm Thickness at the cryogenic temperature. Also it was found that the enhancement of bonding performances strongly depended on the CTE (Coefficient of Thermal Expansion) differences between the stainless steel foil and reinforced Adhesive. Finally an optimum volume fraction of the glass fiber reinforcement was proposed for the newly developed Al-SUS Adhesively bonded joint.

  • Development of a Fatigue Failure Model for the Adhesively Bonded Tubular Single Lap Joint under Dynamic Torsional Loading
    Journal of Adhesion, 1996
    Co-Authors: Su Jeong Lee, Dai Gil Lee
    Abstract:

    Abstract The Adhesively bonded tubular single lap joint shows nonlinear torque transmission capability and deformation characteristics under static torsional loading because of nonlinear properties of the Adhesive. However, the dynamic or fatigue torque transmission capability can be calculated with linear, analysis because the stress-strain relation under torsional fatigue loading is linear, due to the small dynamic transmission capability compared with the static torque transmission capability. In this paper, a failure model for the Adhesively bonded tubular single lap joint under torsional fatigue loading was developed with respect to the Adhesive Thickness, which is the critical factor for the static torque transmission capability. Also, a design method for the Adhesively bonded tubular single lap joint under torsional fatigue loading was proposed.

  • an experimental study of the static torque capacity of the Adhesively bonded tubular single lap joint
    Journal of Adhesion, 1996
    Co-Authors: Jin Ho Choi, Dai Gil Lee
    Abstract:

    With the wide application of fiber-reinforced composite materials in aircraft, space structures and robot arms, the design and manufacture of composite joints have become a very important research area because they are often the weakest areas in composite structures. In this study, the effects of the Adhesive Thickness and tensile thermal residual stress on the torque capacity of tubular single lap joints were studied. The torque capacities of the Adhesive joints were experimentally determined and found to be inversely proportional to the Adhesive Thickness. In order to match the experimental results to the theoretical analyses, the elastic-perfectly plastic material properties of the Adhesive were used in the closed form solution. Also, the tensile thermal residual stresses of the joints were calculated by the finite element method and it was found that the thermal residual stresses could play an important role in the torque capacity when the Adhesive Thickness was large.

Benali Boutabout - One of the best experts on this subject based on the ideXlab platform.