Adhesive Butt Joints Research Articles

Two-Dimensional Stress Analysis and Strength of Band Adhesive Butt Joints of Dissimilar Adherends Subjected to Cleavage Loads.

The stresses of band adhesive butt joints, in which the interfaces were partially bonded, were analyzed using a two-dimensional theory of elasticity, in order to establish the fracture criteria when the joints of dissimilar adherends were subjected to cleavage loads. In the analysis, the dissimilar adherends and the adhesive were replaced with finite strips when the interfaces were bonded by an adhesive at two regions. In the numerical calculations, the effects of the ratios of Young's modulus among adherends and an adhesive, and the thickness of the adhesive, the bonding area and the position on the stress distributions at the interfaces were demonstrated. As a result, it was seen that band adhesive joints were available when the bonding area and positions were determined taking into account external loads distributions. For verification, experiments were performed on the strains of adherends and the joint strength. The analytical results were consistent with the experimental ones.

Stress analysis and testing of parallel and tapered adhesive butt joints

A correlation between numerical results obtained by the finite element (FE) method and experimental data for parallel and tapered butt joints under tensile load was investigated. Two linear FE simulations were constructed for both joints and the numerical results were used in understanding the ultimate strength and failure modes. The data provided the ultimate tensile strength and failure modes for various thicknesses of polyurethane adhesive bonded between polycarbonate and aluminum adherends. The numerical and test data results show that a thinner parallel adhesive layer leads to a stronger joint. An optimum adhesive layer thickness was found for the tapered configuration (0.4-0.5 mm). This thickness was achieved when the stress value and its gradient were distributed in an optimal ratio. Then the mode of failure was changed from interfacial to cohesive. The enhanced sensitivity found for the tapered joint strength as a function of its thickness leads to the conclusion that in real bonded structures it should be avoided. In addition to other important parameters, i.e. surface treatment and material properties which ensure high strength and durable adhesive joints, any existing tapered angle of the adhesive layer should be minimized.

Two-Dimensional Stress Analysis and Strength Evaluation of Band Adhesive Butt Joints of Dissimilar Adherends Subjects to Tensile Loads.

The stress of band adhesive butt joints in which the interfaces are partially bonded, was analyzed using a two-dimensional, theory of elasticity in order to establish fracture criteria for the case in which the joints of dissimilar adherends are subjected to tensile loads. In the analysis, when the interfaces are bonded by an adhesive at two regions, the dissimilar adherends and the adhesive are replaced with finite strips. In the numerical calculations, the effects of the ratio of Young's modulus of adherends to that of adhesives, the thickness of the adhesives, the bonding area and position and load distributions on the stress distributions at the interfaces were demonstrated. In addition, with use of the stress distribution, a method for evaluating joint strength was proposed. As a result, it was observed that band adhesive joints were available when the bonding area and positions were varied taking into account external load distribution. For verification, experiments were performed on the strain of adherends and the joint strength. Analytical results were consistent with the experimental ones.

Analysis of Failure Properties and Strength of Structural Adhesive Joints with Damage Mechanics

The present paper deals with the strength and failure properties of adhe sive joints weakened by initial imperfections such as flaws or debonding of the interface. The problem is analyzed by applying the principles of the newly developed damage mechanics with suitable modifications made to accommodate the inherent physical and mechanical properties of structural adhesives. The reduction in effective load-carrying area due to damage accumulation is represented by a symmetric damage tensor of second rank that is related to the decrease of elastic modulus via a hypothesis of energy equiva lence. Damage evolution is assumed to be controlled by the dilatational part of total en ergy. The model is then implemented onto a finite element program by using the updated Lagrangian formulation. A butt adhesive joint weakened by a central crack in the adhesive is subsequently analyzed to demonstrate the potential capability of the damage model. Detailed stress and damage distributions in the near and far fields are given as functions of adherend/adhesive modulus ratio. The issue of fracture initiation angle and fracture load is also studied by applying two novel damage fracture criteria.

Two-Dimensional Thermal Stress Analysis of Butt Adhesive Joint Having Rigid Fillers in the Adhesive.

Thermal stress distribution and thermal strength were examined when butt adhesive joints with rigid fillers in an adhesive were in steady-state temperature distribution. In the analyses, the thermal stress distribution in the adhesive was given using the two-dimensional theory of elasticity in the case where adherends composed of the same size and the rigid material were kept at a constant temperature and the side surfaces of the joint were surrounded with fluid of a different temperature. Numerical calculations showed that the thermal stress was tensile near the end of the interface between the adherend and the adhesive and around the interface where the filler was included underneath, the thermal stress concentrated at the periphery of the filler, and large concentration of thermal stress was generated when the filler size was large. Photoelastic experiments were carried out, and the analytical results were consistent with the experimental ones.

A Two-Dimensional Stress Analysis of Butt Adhesive Joints Filled with Rigid Circular Fillers in an Adhesive Subjected to Tensile Loads

This paper deals with a two-dimensional stress analysis of a butt adhesive joint with rigid fillers in an adhesive subjected to a tensile load. Assuming that adherends are rigid and replacing an adhesive with a finite strip including rigid fillers, the analysis was done using the two-dimensional theory of elasticity in order to examine the joint strength. The effects of the location and size of rigid fillers on the stress distributions around the fillers and at the interfaces were shown by numerical calculations. For verification, photoelastic experiments were performed. The analytical result was in fairly good agreement with the experimental result. It was seen that based on the amount of shift of the location and the filler diameter, the joint strength was more improved than that of the joints without fillers.

A Two-Dimensional Stress Analysis of a Butt Adhesive Joint Filled with Rigid Circular Fillers in the Adhesive Subjected to a Cleavage Load.

This paper deals with a two-dimensional stress analysis of a butt adhesive joint with rigid fillers in the adhesive subjected to a cleavage load. Similar adherends were replaced with finite strips, and an adhesive was replaced with a finite strip including rigid fillers. The analysis was done using the two-dimensional theory of elasticity in order to evaluate the joint strength. The effects of the location and size of rigid fillers on the stress distributions around the fillers and at the inter face were shown by numerical calculations. An experiment concerning the strains of adhesive was performed. The analytical result was consistent with the experimental result. It was seen that with an increase of the shift of location and size of fillers, the joint strength increased more than that of the joint without a filler. The stress singularity at the edge of the interface was discussed.

Two-Dimensional Thermal Stress Analysis of Butt Adhesive Joints

Thermal stress distribution in a butt adhesive joint composed of two finite thin plates, of which both end surfaces are kept at a constant temperature and the other surfaces at a different temperature, is analyzed using the two-dimensional theory of elasticity. In the case where the joint is made of similar adherends and kept at the same high temperature at both free end surfaces of the joint, it is seen that the maximum tensile stress occurs at the end of the interface between the adherend and the adhesive, and compressive stress around the center of the interface. The effects of the ratios of the coefficient of thermal expansion, Young's modulus and the thickness of the adherend to those of the adhesive on the thermal stress distributions are obtained by numerical calculations. Moreover, in the case where the adherbnds are kept at different temperatures at each free end surface of the joint, the thermal stress distributions at each interface are obtained numerically. For verification, the thermal strain distribution near the interface was measured using strain gauges, and also, the photoelastic experiment was carried out on the joint where an epoxy resin plate was used as an adhesive. The analytical results were satisfactorily consistent with the experimental ones.

The Strength of Joints Combinging Adhesion with Tap Bolts. The Case where Adherends are Hollow Cylinders and T-Flanges.

This paper deals with the strength of joints that combine adhesion and tap bolts. When an external load was applied to a combination joint formed after joining two hollow cylinders by adhesion, they were clamped by a tap bolt with an initial clamping force, and the stress distributions in the adhesives and the variation of the bolt axial force were analyzed using an axisymmetric theory of elasticity. In addition, a method to estimate the strength of the combination joint was proposed. Experiments were performed. The analytical results are consistent with the experimental results concerning the variation of the bolt axial force and the joint strength. It is seen that the strength of the combination joint increases as the length of the tap bolt increases. Furthermore, the strength of the T-type butt adhesive joint combined with tap bolts was examined from both analyses and experiments. The characteristics of the combination joint were clarified.

Two-Dimensional Thermal Stress Analysis of Butt Adhesive Joints Having Circular Hole Defects in the Adhesive.

Two-Dimensional Thermal Stress Analysis of Butt Adhesive Joints Having Circular Hole Defects in the Adhesive.

A Two-Dimensional Stress Analysis and Strength of Band Adhesive Butt Joints of Dissimilar Adherends Subjected to Externl Bending Moments.

The stresses of band adhesive butt joints, in which the interfaces were partially bonded, were analyzed using a two-dimensional theory of elasticity in order to establish the fracture criteria when the joints of dissimilar adherends were subjected to external bending moments. In the analysis, the dissimilar adherends and the adhesive were replaced with finite strips when the interfaces were bonded by an adhesive at two regions. In the numerical calculations, the effects of the ratios of Young's modulus among adherends and an adhesive, the thickness of the adhesive, the bonding area and the position on the stress distributions at the interfaces were demonstrated. As a result, it was seen that band adhesive joints were available when the bonding area and positions were determined taking into account the external load distributions. Experiments were performed on the strains of adherends and the joint strengths. Analytical results were consistent with the experimental ones.

A Stress Analysis of Adhesive Butt Joints of Dissimilar Materials Subjected to Cleavage Loads

Abstract Stress distributions are examined when an adhesive butt joint, in which two thin plates made of dissimilar materials are joined, is subjected to cleavage loads. General representations of the stress and displacement fields are given using the two-dimensional theory of elasticity. The effects of the ratios of young's modulus among two adherends and an adhesive and the thickness of the adhesive on the stress distributions of the joints are clarified by numerical calculations. In addition, the stress singularity near the edge of the interface in the load application side is evaluated. For verification, the strain distributions near the interface of each adherend were measured. The analytical results are closely consistent with the experimental ones.

A Two-Dimensional Thermal Stress Analysis of Butt Adhesive Joints.

Thermal stress distribution in a butt adhesive joint composed of two finite thin plates, in which both end surfaces are kept at higher temperatures and the other surfaces at lower temperatures, is analyzed using the two-dimensional theory of elasticity. In case of the joint with similar adherends kept at the same higher temperature at both free end surfaces of the joint, it is seen that the maximum tensile stress occurs at the edge of the interface between the adherends and the adhesive and compressive stress around the center of the interface. The effects of the ratios of the coefficient of thermal expansion, Young's modulus and the thickness of the adherend to those of the adhesive on the thermal stress distributions are obtained by the numerical calculations. Moreover, in the case of the adherends kept at different temperatures at each free end surface, thermal stress distributions at each interface are obtained numerically. For verification, the thermal strain distribution near the interface was measured using strain gages and also the photoelastic experiment was carried out on the joint where an epoxy resin plate was used as an adhesive. The analytical results were satisfactorily consistent with the experimental ones.

The Effect of Acting Period of Stress Wave and Alternating Modes on the Fracture Strength of Adhesive Bull Joint.

The fracture strength of the adhesive butt joint of a round steel bar bonded by cyano-acrylate for tensile stress waves and alternating waves was measured experimentally. The tensile stress wave initiates in the round bar with the adhesive butt joint as the anvil attached at the end of the bar is struck by the dropping a circular cylinder. The alternating stress waves, which change from compressive to tensile, repeatedly propagate in the longer bar, as two bars of unequal length coaxially collide into each other. The location of the joint is designed to agree with the position at which the intermittent or serial alternating stress waves are observed. The fracture strength of the adhesive decreases as the acting period of waves increases. The fracture strength for intermittent waves is larger than for serial waves. The dynamic fracture strength was compared with the result for static fracture strength.

A Two-dimensional Stress Analysis of Butt Adhesive Joints Having a Circular Hole Defect in the Adhesive Subjected to External Bending Moments

Abstract This paper deals with a two-dimensional stress analysis of butt adhesive joints, with a circular hole defect in the adhesive, subjected to external bending moments. The analysis was done using the two-dimensional theory of elasticity in order to examine the strength of the joints. It was assumed that the adherends were rigid and the adhesive was replaced with a finite strip including a hole defect. The effects of the location and size of a hole defect on the stress distributions around the hole and at the interfaces were obtained by numerical calculations. In addition, the singular stress near the edge of the interface was obtained. For verification, photoelastic experiments were performed. The analytical results were fairly consistent with the experimental results. It was seen that the principal stress around a hole becomes larger with a certain shift toward the free boundary. It was also seen that the stress concentration became larger with an increase of the size of the hole.

A Two-Dimensional Stress Analysis of Butt Adhesive Joints Filled With Rigid Circular Fillers in an Adhesive Subjected to External Bending Moments.

This paper deals with a two-dimensional stress analysis of butt adhesive joints with rigid fillers in an adhesive subjected to external bending moments. Assuming that adherends are rigid, and replacing an adhesive with a finite strip including rigid fillers, the analysis was performed using the two-dimensional theory of elasticity in order to examine the strength of joints. The effects of the location and size of rigid fillers on the stress distributions around the fillers and at the interface were shown by numerical calculations. For verification, photoelastic experiments were performed. The analytical result was in fairly good agreement with the experimental result. It was seen that due to the amount of shift of location and size of fillers, the strength of joint was more improved than that of the joints without a filler. The stress singularity at the edge of the interface was discussed.

Two-dimensional stress analysis of adhesive butt joints subjected to cleavage loads

This paper deals with the two-dimensional stress analysis of adhesive butt joints subjected to cleavage loads. The purpose of the paper is to contribute to the establishment of fracture criteria of adhesive joints. Similar adherends and an adhesive bond are replaced with finite strips in the analysis. Stress distributions in adhesive joints are analysed using the two-dimensional theory of elasticity. The effects of the ratio of Young's modulus of adherends to that of an adhesive and the thickness of the adhesive bonds on the stress distributions are shown by numerical calculations. For verification, strains produced on adherends are experimentally measured and a photoelastic experiment is carried out. The analytical results are in fairly good agreement with experiment.

Three-dimensional stress analysis of adhesive butt joints having the disbonded area and the spew fillet

Three-dimensional stress analysis of adhesive butt joints having the disbonded area and the spew fillet

Two-dimensional stress analysis of adhesive butt joints subjected to cleavage loads

Two-dimensional stress analysis of adhesive butt joints subjected to cleavage loads

Three-dimensional stress analysis of adhesive butt joints with disbonded areas and spew fillets

This paper deals with three-dimensional stress analysis of adhesive butt joints subjected to tensile loads, to help establish fracture criteria. In this analysis, the adherends and adhesive bond are replaced with finite solid culinders. Stress distributions in adhesive joints are analysed using a three-dimensional theory of elasticity. The effects of a disbonded area and a spew fillet on the principal stress distributions are shown by numerical calculation. Where a joint has a disbonded area, the stress singularity increases with a decrease in the diameter of the spew fillet, and the stress singularity decreases with an increase in the diameter of the adhesive. The analytical result is compared with that obtained by an experiment concerning the strain produced on the adherends in the case of a disbonded area. Both results are satisfactorily consistent.