• Journal of Welding and Joining
• /
• v.19 no.3
• /
• pp.342-347
• /
• 2001

Recently, adhesive-bonding technique is wifely used in manufacturing structures. Stress and strain analysis of joints are essential to design adhesive-bonded joints structure. The single-lap adhesive joint is the design dominating the range of adhesive joints. In this study, single-lap specimens with different joint dimensions were used for the tensile-shear test and finite element calculation in of order to investigate the effect of overlap length and adhesive-bonding thickness on adhesive strength and stress distribution of the joints. Consequently, it was found that overlap lap size and thickness can be important parameters of structure joints using adhesive bonding, which is effected on adhesive strength.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.21 no.3
• /
• pp.439-445
• /
• 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.

• Journal of the Society of Disaster Information
• /
• v.15 no.2
• /
• pp.259-267
• /
• 2019

Purpose: In this paper adhesive-bonded cylindrical lap joints are analyzed by assuming that the adherends are elastic and the adhesive is linearly viscoelastic. Method: The distribution of the stresses in the adhensive is evaluated using the Finite Element Method. Nuverical examples for identical and different adherends bonded through a four parameter viscoelastic solid adhesive are illustrated. Results: The stress distribution in the adhesive layer with respect to time is shown. The stress distribution in the adhesive layer with respect to time is shown. The results are also shown that adherend thickness and elastic modulus give effect on the normalized stress. Conclusion: In this study, the stress distribution of the adhesive layer of the wrapped cylindrical body considering the viscoelasticity of the adhesive layer was numerically analyzed by using a four - element elastomer model.

• Computers and Concrete
• /
• v.15 no.3
• /
• pp.337-355
• /
• 2015

In this scientific work, an improved analytical solution for adhesive stresses in a concrete beam bonded with the FRP plate is developed by including the effect of the adherend shear deformations. The analysis is based on the deformation compatibility approach where both the shear and normal stresses are assumed to be invariant across the adhesive layer thickness. The shear stress distribution is supposed to be parabolic across the depth of the adherends in computing the adhesive shear stress and Timoshenko's beam theory is employed in predicting adhesive normal stress to consider the shear deformation. Numerical results from the present analysis are presented both to demonstrate the advantages of the present solution over existing ones and to illustrate the main characteristics of adhesive stress distributions.

• Journal of the Semiconductor & Display Technology
• /
• v.17 no.1
• /
• pp.35-39
• /
• 2018

This paper deals with the relaxation of singular stresses developed in an epoxy adhesive at high temperature. The interface stresses are analyzed using BEM. The adhesive employed in this study is an epoxy which can be cured at room temperature. The adhesive is assumed to be linearly viscoelastic. First, the distribution of the interface stresses developed in the adhesive layer under the uniform tensile stress has been calculated. The singular stress has been observed near the interface corner. Such singular stresses near the interface corner may cause epoxy layer separated from adherent. Second, the interfacial thermal stress has been investigated. The uniform temperature rise can relieve the stress level developed in the adhesive layer under the external loading, which can be viewed as an advantage of thermal loading. It is also obvious that temperature rise reduces the bonding strength of the adhesive layer. Experimental evaluation is required to assess a trade-off between the advantageous and deleterious effects of temperature.

• Structural Engineering and Mechanics
• /
• v.83 no.5
• /
• pp.693-707
• /
• 2022

Bonded joints have proven their performance against conventional joining processes such as welding, riveting and bolting. The single-lap joint is the most widely used to characterize adhesive joints in tensile-shear loadings. However, the high stress concentrations in the adhesive joint due to the non-linearity of the applied loads generate a bending moment in the joint, resulting in high stresses at the adhesive edges. Geometric optimization of the bonded joint to reduce this high stress concentration prompted various researchers to perform geometric modifications of the adhesive and adherends at their free edges. Modifying both edges of the adhesive (spew) and the adherends (bevel) has proven to be an effective solution to reduce stresses at both edges and improve stress transfer at the inner part of the adhesive layer. The majority of research aimed at improving the geometry of the plate and adhesive edges has not considered the effect of temperature and water absorption in evaluating the strength of the joint. The objective of this work is to analyze, by the finite element method, the stress distribution in an adhesive joint between two 2024-T3 aluminum plates. The effects of the adhesive fillet and adherend bevel on the bonded joint stresses were taken into account. On the other hand, degradation of the mechanical properties of the adhesive following its exposure to moisture and temperature was found. The results clearly showed that the modification of the edges of the adhesive and of the bonding agent have an important role in the durability of the bond. Although the modification of the adhesive and bonding edges significantly improves the joint strength, the simultaneous exposure of the joint to temperature and moisture generates high stress concentrations in the adhesive joint that, in most cases, can easily reach the failure point of the material even at low applied stresses.

• Structural Engineering and Mechanics
• /
• v.88 no.6
• /
• pp.609-623
• /
• 2023

The objective of this study is to investigate the distribution of von Mises stress, peeling stress, and shear stress in the adhesive layer used to bond two composite panels, considering various parameters using a three-dimensional finite element method. The stiffness of the materials and the effect of the stacking order on the amount of load transferred to the adhesive layer were examined to determine which type of laminate generates less stress at the bond line. The study analyzed six different stacking sequences, all with a common first layer in contact with the adhesive and a 0° orientation. Additionally, the impact of using hybrid composites on reducing bond line stress was investigated.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.17 no.3
• /
• pp.14-19
• /
• 2008

In the semiconductor IC(Integrated Circuit) package, the top surface of silicon chip is directly attached to the area of the leadframe with a double-sided adhesive layer, in which the base layer have the upper adhesive layer and the lower adhesive layer. The IC package structure has been known to encounter a thermo-mechanical failure mode such as delamination. This failure mode is due to the residual stress on the adhesive surface of silicon chip and leadframe in the curing-cooling process. The induced thermal stress in the curing process has an influence on the cooling residual stress on the silicon chip and leadframe. In this paper, for the minimization of the chip surface damage, the adhesive topologies on the silicon chip are studied through the finite element analysis(FEA).

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2011.11a
• /
• pp.933-937
• /
• 2011

In order to determine optimal design length of adhesive joint of a composite pressure vessel with separated dome, stress analysis of joint part according to changes of adhesive length was done. Adhesive length has a range of 50mm to 300mm as design variables. The ratio of adhesive length with any stress gradient to initial non-stressed adhesive length was called "stress gradient length ratio" and selected as objective function. The stress gradient length ratio of joint part with adhesive length of more than 200mm was increased very slowly with increase of adhesive length. It means that adhesive length of about 200mm could be the optimal value to ensure the structural safety of joint part against internal pressure of 2,500 psi.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.16 no.10
• /
• pp.1841-1852
• /
• 1992

With the wide application of fiber-reinforced composite material 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, residual thermal stress on the torque capacity of the tubular single lap joints were studied. The torque capacity of the adhesive joints were experimentally determined and found to be inversely proprotional 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 residual thermal stress of the joints were calculated by the finite element method and it was proved that the residual thermal stress could play an important role in the thick adhesive joints.