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Recep Gunes - One of the best experts on this subject based on the ideXlab platform.
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elastic flexural behaviour of an adhesively bonded single lap joint with functionally graded Adherends
Materials & Design, 2007Co-Authors: Kemal M Apalak, Recep GunesAbstract:Abstract This study investigates three-dimensional elastic flexural behaviour of an adhesively bonded single lap joint with Adherends composed of a functionally gradient layer between a pure ceramic (Al2O3) layer and a pure metal (Ni) layer. The in-plane normal stress and shear stresses were critical in the Adherends and adhesive layer. The left free edge of the upper adherend–adhesive interface, the right free edge of the lower adherend–adhesive interface and the corresponding zones in the upper and lower Adherends experience stress concentrations whereas the middle overlap region has a uniform low stress distribution. The normal stress varies linearly through the adherend thickness and then becomes peak in the ceramic layer and in the metal layer. In the adhesive layer, the normal stress is peak at the left free edge of the upper adherend–adhesive interface and at the right free edge of the lower adherend–adhesive interface and then decreases uniformly across the adhesive layer towards the other adherend–adhesive interface. The functionally gradient region composed of layers with the mechanical properties calculated based on the power law. Accordingly, increasing the layer number had a minor effect on the through-the-thickness profiles and magnitudes of the critical stresses in both the Adherends and the adhesive layer. In addition, enriching the material composition of the functionally gradient region with the ceramic phase does not affect the through-the-thickness profiles of critical normal and shear stresses of both Adherends and adhesive whereas their magnitudes in the ceramic-rich layer of both Adherends and along the adherend–adhesive interfaces increase considerably. On the contrary, the layer number and compositional gradient component affect evidently the through-the-thickness profiles and magnitudes of the critical normal and shear stresses in the Adherends and adhesive layer of the functionally graded adhesively bonded joints subjected to thermal loads.
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thermal residual stresses in an adhesively bonded functionally graded single lap joint
Journal of Adhesion Science and Technology, 2006Co-Authors: Kemal M Apalak, Recep GunesAbstract:This study investigates three-dimensional thermal residual stresses occurring in an adhesively-bonded functionally graded single-lap joint subjected to a uniform cooling. The Adherends are composed of a through-the-thickness functionally graded region between Al2O3 ceramic and Ni metal layers. Their mechanical properties were calculated using a power law for the volume fraction of the metal phase and a 3D layered finite element was implemented. In a free single-lap joint the normal stress σxx was dominant through the overlap region of the upper and lower Adherends and along the adhesive free edges, whereas the transverse shear stress σxy concentrations appeared only along the free edges. The peel stress σyy and the transverse shear stress σxy became dominant along the free edges of the adhesive layer. In addition, the von Mises stress decreased uniformly through the adherend thickness from compressive in the top ceramic-rich layer to tensile in the bottom metal-rich layer. In addition, the layer number ha...
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investigation of elastic stresses in an adhesively bonded single lap joint with functionally graded Adherends in tension
Composite Structures, 2005Co-Authors: Kemal M Apalak, Recep GunesAbstract:Abstract In this study three-dimensional elastic stress state of an adhesively bonded single lap joint with functionally graded Adherends in tension was investigated. The Adherends compose of a functionally gradient layer between a pure ceramic (Al 2 O 3 ) layer and a pure metal (Ni) layer. Stress concentrations are observed along the free edges of the adhesive layer and through the corresponding zones in the upper and lower Adherends. The adhesive layer experiences stress concentrations along the left and right free edges in the horizontal plane, and the normal stresses and the shear stress σ xy are critical. Whereas the middle overlap region has a uniform low stress distribution the zones in the upper adherend corresponding to the left free edge of the adhesive layer and the zones in the lower adherend corresponding to the right free edge of the adhesive layer are subjected to higher stresses. The normal stress σ xx among the normal stresses and the shear stress σ xy among the shear stresses are dominant in both upper and lower Adherends. The normal stress σ xx changes uniformly from compression in the ceramic layer to tension in the metal layer through the upper plate-thickness and from tension in the ceramic layer to compression in the metal layer through the lower plate-thickness. In the adhesive layer, the normal stress σ yy becomes peak at the left free edge of the upper adherend–adhesive interface and at the right free edge of the lower adherend–adhesive interface and then decreases uniformly across the adhesive layer towards the other adherend–adhesive interface. The functionally gradient region across the adherend thickness was modelled using the layers with the mechanical properties calculated based on the power law. However, a layer number larger than 20 has a minor effect on the through-thickness profiles and magnitudes of von Mises and normal stresses in both the Adherends and the adhesive. In addition, increasing the ceramic phase in the material composition (compositional gradient exponent n ) of the functionally gradient region does not affect the through-thickness profiles of von Mises and normal stresses in the Adherends and adhesive whereas their magnitudes in the ceramic rich layer of both Adherends and along the adherend–adhesive interfaces increase considerably. On the contrary, the layer number and compositional gradient exponent have an evident effect on the through-thickness profiles and magnitudes of the critical stress components in the Adherends and adhesive layer of the functionally graded adhesively bonded joints.
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on non linear thermal stresses in an adhesively bonded single lap joint
Computers & Structures, 2002Co-Authors: Kemal M Apalak, Recep GunesAbstract:Abstract Since adhesive joints consist of adhesive and Adherends with different mechanical and thermal properties, the adhesive and Adherends present different stress and strain states under thermal loads due to the thermal–mechanical mismatches. Thermal strains result in serious stresses even though the adhesive joints are not restrained. In this study, the thermal stress analysis of an adhesively bonded single lap joint (SLJ) was carried out considering the large displacement effects. In the thermal analysis, the outer surfaces of the SLJ are assumed to be subjected to air flows with different temperature and velocity. The final temperature distribution in the adhesive joint was used to compute thermal strains. Later, the geometrical non-linear stress analysis of the SLJ was carried out for four adherend edge conditions using the incremental FEM. Thermal strain concentrations were observed inside the adhesive fillets around the free ends of the adhesive layer. The top and bottom surfaces of the Adherends also experienced high thermal stresses. The detailed analysis showed that the most critical adhesive regions were the free ends of the adhesive–adherend interfaces. It was observed that thermal loads caused serious stress and strain concentrations in joint members as well as the structural loads (Structural adhesive joints in engineering. London: Elsevier Applied Science; 1984). In order to reduce the peak stresses at the critical adhesive and adherend regions increasing the overlap length was not beneficial for all adherend edge conditions.
Kemal M Apalak - One of the best experts on this subject based on the ideXlab platform.
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elastic flexural behaviour of an adhesively bonded single lap joint with functionally graded Adherends
Materials & Design, 2007Co-Authors: Kemal M Apalak, Recep GunesAbstract:Abstract This study investigates three-dimensional elastic flexural behaviour of an adhesively bonded single lap joint with Adherends composed of a functionally gradient layer between a pure ceramic (Al2O3) layer and a pure metal (Ni) layer. The in-plane normal stress and shear stresses were critical in the Adherends and adhesive layer. The left free edge of the upper adherend–adhesive interface, the right free edge of the lower adherend–adhesive interface and the corresponding zones in the upper and lower Adherends experience stress concentrations whereas the middle overlap region has a uniform low stress distribution. The normal stress varies linearly through the adherend thickness and then becomes peak in the ceramic layer and in the metal layer. In the adhesive layer, the normal stress is peak at the left free edge of the upper adherend–adhesive interface and at the right free edge of the lower adherend–adhesive interface and then decreases uniformly across the adhesive layer towards the other adherend–adhesive interface. The functionally gradient region composed of layers with the mechanical properties calculated based on the power law. Accordingly, increasing the layer number had a minor effect on the through-the-thickness profiles and magnitudes of the critical stresses in both the Adherends and the adhesive layer. In addition, enriching the material composition of the functionally gradient region with the ceramic phase does not affect the through-the-thickness profiles of critical normal and shear stresses of both Adherends and adhesive whereas their magnitudes in the ceramic-rich layer of both Adherends and along the adherend–adhesive interfaces increase considerably. On the contrary, the layer number and compositional gradient component affect evidently the through-the-thickness profiles and magnitudes of the critical normal and shear stresses in the Adherends and adhesive layer of the functionally graded adhesively bonded joints subjected to thermal loads.
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thermal residual stresses in an adhesively bonded functionally graded single lap joint
Journal of Adhesion Science and Technology, 2006Co-Authors: Kemal M Apalak, Recep GunesAbstract:This study investigates three-dimensional thermal residual stresses occurring in an adhesively-bonded functionally graded single-lap joint subjected to a uniform cooling. The Adherends are composed of a through-the-thickness functionally graded region between Al2O3 ceramic and Ni metal layers. Their mechanical properties were calculated using a power law for the volume fraction of the metal phase and a 3D layered finite element was implemented. In a free single-lap joint the normal stress σxx was dominant through the overlap region of the upper and lower Adherends and along the adhesive free edges, whereas the transverse shear stress σxy concentrations appeared only along the free edges. The peel stress σyy and the transverse shear stress σxy became dominant along the free edges of the adhesive layer. In addition, the von Mises stress decreased uniformly through the adherend thickness from compressive in the top ceramic-rich layer to tensile in the bottom metal-rich layer. In addition, the layer number ha...
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investigation of elastic stresses in an adhesively bonded single lap joint with functionally graded Adherends in tension
Composite Structures, 2005Co-Authors: Kemal M Apalak, Recep GunesAbstract:Abstract In this study three-dimensional elastic stress state of an adhesively bonded single lap joint with functionally graded Adherends in tension was investigated. The Adherends compose of a functionally gradient layer between a pure ceramic (Al 2 O 3 ) layer and a pure metal (Ni) layer. Stress concentrations are observed along the free edges of the adhesive layer and through the corresponding zones in the upper and lower Adherends. The adhesive layer experiences stress concentrations along the left and right free edges in the horizontal plane, and the normal stresses and the shear stress σ xy are critical. Whereas the middle overlap region has a uniform low stress distribution the zones in the upper adherend corresponding to the left free edge of the adhesive layer and the zones in the lower adherend corresponding to the right free edge of the adhesive layer are subjected to higher stresses. The normal stress σ xx among the normal stresses and the shear stress σ xy among the shear stresses are dominant in both upper and lower Adherends. The normal stress σ xx changes uniformly from compression in the ceramic layer to tension in the metal layer through the upper plate-thickness and from tension in the ceramic layer to compression in the metal layer through the lower plate-thickness. In the adhesive layer, the normal stress σ yy becomes peak at the left free edge of the upper adherend–adhesive interface and at the right free edge of the lower adherend–adhesive interface and then decreases uniformly across the adhesive layer towards the other adherend–adhesive interface. The functionally gradient region across the adherend thickness was modelled using the layers with the mechanical properties calculated based on the power law. However, a layer number larger than 20 has a minor effect on the through-thickness profiles and magnitudes of von Mises and normal stresses in both the Adherends and the adhesive. In addition, increasing the ceramic phase in the material composition (compositional gradient exponent n ) of the functionally gradient region does not affect the through-thickness profiles of von Mises and normal stresses in the Adherends and adhesive whereas their magnitudes in the ceramic rich layer of both Adherends and along the adherend–adhesive interfaces increase considerably. On the contrary, the layer number and compositional gradient exponent have an evident effect on the through-thickness profiles and magnitudes of the critical stress components in the Adherends and adhesive layer of the functionally graded adhesively bonded joints.
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on non linear thermal stresses in an adhesively bonded single lap joint
Computers & Structures, 2002Co-Authors: Kemal M Apalak, Recep GunesAbstract:Abstract Since adhesive joints consist of adhesive and Adherends with different mechanical and thermal properties, the adhesive and Adherends present different stress and strain states under thermal loads due to the thermal–mechanical mismatches. Thermal strains result in serious stresses even though the adhesive joints are not restrained. In this study, the thermal stress analysis of an adhesively bonded single lap joint (SLJ) was carried out considering the large displacement effects. In the thermal analysis, the outer surfaces of the SLJ are assumed to be subjected to air flows with different temperature and velocity. The final temperature distribution in the adhesive joint was used to compute thermal strains. Later, the geometrical non-linear stress analysis of the SLJ was carried out for four adherend edge conditions using the incremental FEM. Thermal strain concentrations were observed inside the adhesive fillets around the free ends of the adhesive layer. The top and bottom surfaces of the Adherends also experienced high thermal stresses. The detailed analysis showed that the most critical adhesive regions were the free ends of the adhesive–adherend interfaces. It was observed that thermal loads caused serious stress and strain concentrations in joint members as well as the structural loads (Structural adhesive joints in engineering. London: Elsevier Applied Science; 1984). In order to reduce the peak stresses at the critical adhesive and adherend regions increasing the overlap length was not beneficial for all adherend edge conditions.
Toshiyuki Sawa - One of the best experts on this subject based on the ideXlab platform.
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experimental and fem studies on mechanical properties of single lap adhesive joint with dissimilar Adherends subjected to impact tensile loadings
International Journal of Adhesion and Adhesives, 2013Co-Authors: Lijuan Liao, Toshiyuki Sawa, Chenguang HuangAbstract:The rupture initiation position, the stress wave propagations and interface stress distributions of the single-lap adhesive joint with dissimilar Adherends under impact tensile loadings are analyzed via experiments combined with FEM calculations taking account of the strain rate dependency property of the adhesive. It is obtained that rupture initiates at the interface of the adherend with higher Young's modulus (steel side in this study) in the joint under impact tensile loadings, which shows the opposite characteristic in the same type of joint under static loadings. A fairly good agreement is observed between the experimental measured and FEM calculated results. In addition, it is also found that the strength of the joint with dissimilar Adherends is smaller than that of the joint with similar Adherends when the joint is subjected to the impact tensile loadings owing to the different extent of the wave impedance mismatch which depends on the material properties. Finally, the design guideline for the single-lap adhesive joint is summarized and provided.
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a three dimensional finite element stress analysis and strength prediction of stepped lap adhesive joints of dissimilar Adherends subjected to bending moments
International Journal of Adhesion and Adhesives, 2010Co-Authors: Toshiyuki Sawa, Kohei Ichikawa, Yuichiro Shin, Takashi KobayashiAbstract:Abstract Stress distributions in stepped-lap adhesive joints of dissimilar Adherends subjected to bending moments are analyzed using a three-dimensional finite-element method (FEM). For establishing an optimum design method of the joints, the effects of some factors are examined. The results show that the maximum value of the maximum principal stress σ1 occurs at the butted edge of the adherend’s interfaces with higher Young’s modulus. The maximum value of σ1 increases as the Young’s modulus ratio between the dissimilar Adherends and the adhesive thickness increase while it decreases as the number of steps increases. In addition, the joint strength is predicted using an elasto-plastic stress analysis. For verification of the FEM calculations, experiments were carried out to measure the strains at the interfaces and the joint strengths. Fairly good agreements were found between the numerical and the experimental results. The joint strength of dissimilar Adherends was found to be smaller than that of similar Adherends.
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a stress analysis and strength estimation of stepped lap adhesive joints under static and impact tensile loadings
ASME 2005 International Mechanical Engineering Congress and Exposition, 2005Co-Authors: Toshiyuki Sawa, Kohei IchikawaAbstract:The stress variations and stress distributions in stepped-lap adhesive joints of dissimilar Adherends under impact tensile loadings were analyzed in elastic range using three-dimensional finite element method. The impact loadings were applied to the lower adherend by dropping a weight. The stress distributions in stepped-lap adhesive joints of dissimilar Adherends under static tensile loadings were also analyzed using FEM. The effects of Young’s modulus of the Adherends, the adhesive thickness and the number of butted steps of adherents ware examined under both impact and static loadings. As the results, The maximum value of stress σ1 increased as Young’s modulus of the Adherends increased for the impact loadings. The maximum value of stress σ1 increased as the numbers of steps in the Adherends increased for the static loadings. In addition, the experiments to measure the strain response of joints subjected to impact tensile loadings were carried out using strain gauges. A fairly good agreement was found between the numerical and the measured results concerning the strain responses.Copyright © 2005 by ASME
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three dimensional finite element stress analysis of single lap adhesive joints of dissimilar Adherends subjected to impact tensile loads
Journal of Adhesion Science and Technology, 2003Co-Authors: Toshiyuki Sawa, Izumi Higuchi, Hidekazu SugaAbstract:The stress-wave propagations and stress distributions in single-lap joints of dissimilar Adherends were analyzed using an elastic three-dimensional finite-element method (DYNA3D). An impact tensile load was applied to the single-lap adhesive joint by dropping a weight. One end of the upper adherend in the single-lap adhesive joint was fixed and the other adherend (lower adherend) which was connected to a bar was impacted by the weight. The effects of Young's modulus and the thickness of each adherend on the stress wave propagations and stress distributions at the interfaces were examined. It was found that the maximum value of the maximum principal stress occurred near the edge of the interface of the fixed adherend. The maximum principal stress increased as Young's modulus of the fixed adherend increased. It was also observed that the maximum principal stress increased as the fixed adherend thickness decreased. In addition, strain responses in the single-lap adhesive joints of dissimilar Adherends subjec...
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stress analysis and strength evaluation of single lap band adhesive joints of dissimilar Adherends subjected to external bending moments
Journal of Adhesion Science and Technology, 2000Co-Authors: Jiemin Liu, Toshiyuki SawaAbstract:Single-lap band adhesive joints of dissimilar Adherends subjected to external bending moments are analyzed as a four-body contact problem using a two-dimensional theory of elasticity (plane strain state). In the analysis, the upper and lower Adherends and the adhesive which are bonded in two regions are replaced by finite strips. In the numerical calculations, the effects of the ratio of Young's moduli of the Adherends, the ratio of the adherend thicknesses, and the ratio of the band length to the half lap length on the stress distributions at the interfaces are examined. A method for estimating the joint strength is proposed using the interface stress and strain obtained by the analysis. An elasto-plastic finite element analysis (EP-FEA) was conducted for predicting the joint strength more exactly. Experiments to measure strains and the joint strength were also carried out. The results show that the strength of a single-lap band adhesive joint is almost the same as that of a single-lap adhesive joint in ...
Thomas Keller - One of the best experts on this subject based on the ideXlab platform.
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ductile double lap joints from brittle gfrp laminates and ductile adhesives part ii numerical investigation and joint strength prediction
Composites Part B-engineering, 2008Co-Authors: Julia Castro, Thomas KellerAbstract:Joint analysis using a non-linear finite element model has been performed to analyze the effects of adhesive ductility on the stiffness and strength of full-scale adhesively-bonded double-lap joints composed of brittle pultruded GFRP laminates. Experimental and numerical results of joint and specimen elongations and axial strains in the bondline compared well. Calculated stress states at failure location inside the Adherends showed that plastification of ductile adhesives provide uniform load transfer leading to increased joint strength. Joint strength increases almost linearly with increasing overlap length. Flexible and stiff joints are defined depending on the ratio of adhesive-to-adherend modulus. Flexible joints exhibit lower stiffness than the Adherends, while stiff joints provide continuity of structural stiffness. The strength of ductile adhesively-bonded joints was predicted by extending an existing through-thickness shear-tensile-interaction failure criterion developed for brittle joints with epoxy adhesive.
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adhesively bonded lap joints from pultruded gfrp profiles part i stress strain analysis and failure modes
Composites Part B-engineering, 2005Co-Authors: Thomas Keller, Till ValleeAbstract:Quasi-static axial tension experiments were performed in a laboratory environment on epoxy bonded, balanced double-lap and single-lap joints from pultruded GFRP flat sections. Full-scale specimens were used to avoid size effects. Parameters investigated were the overlap length (from 50 to 200mm), the adhesive layer thickness (from 1 to 3mm) and the adherend thickness (from 3 to 12mm). On nine of the double lap joints 40 strain gages were installed to measure the axial strain profiles along the overlaps. The measured axial strain profiles in the joints correlated well with numerical results obtained from a 2D finite element analysis. Failure initiation and progression were observed with a high-speed camera. Failure was initiated by the combination of local through-thickness tensile (peeling) and shear stresses at two different locations: in the adhesive fillet and in the outer fiber-mat layers of the Adherends below the joint edges. Failure propagation always occurred in the outer fiber-mat layers of the Adherends. The through-thickness strength of the adhesive-adherend interface was considerably higher than the through- thickness strength of the interfaces between the fiber- mats. The experimental investigation showed that the ultimate failure load converged to a constant value with increasing overlap length. The adhesive layer thickness had an insignificant influence on the ultimate failure loads and the stress-strain distributions along the overlaps. [All rights reserved Elsevier]
Jung Ju Lee - One of the best experts on this subject based on the ideXlab platform.
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Bond Parameters to Improve Tensile Load Bearing Capacities of Co-cured Single and Double Lap Joints with Steel and Carbon Fiber-epoxy Composite Adherends
2016Co-Authors: Kum Cheol, Jung Ju LeeAbstract:ABSTRACT: A co-cured joining method has several advantages over an adhesively-bonded joining method for its simple manufacturing process. It requires neither an adhesive nor surface treatment of the composite adherend and uses excess resin to bond both Adherends, including composite adherend. In this paper, the effects of bond parameters, including surface roughness on the steel adherend, stacking sequence of the composite adherend, and manufacturing pressure in the autoclave during the bonding process, on tensile load bearing capacities of plate-type co-cured single and double lap joints were investigated experimentally. Bond parameters were related to interfacial parameters such as a contact area and adhesive thickness, which affected the joint strength. Experimental results were explained with respect to all of interfacial parameters and bond parameters through investigating failure surfaces of the steel adherend and a lot of data of tensile load bearing capacities. In order to predict tensile load bearing capacities of co-cured single and double lap joints, we considered two different failure models using stress distributions in both co-cured lap joints obtained from finite element analysis. Finally, optimal conditions to improve the joint strength of co-cured single and double lap joints have been presented. KEY WORDS: co-cured lap joint, tensile load bearing capacity, surface roughness, stacking sequence, manufacturing pressure
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effects of thermal residual stresses on failure of co cured lap joints with steel and carbon fiber epoxy composite Adherends under static and fatigue tensile loads
Composites Part A-applied Science and Manufacturing, 2006Co-Authors: Kum Cheol Shin, Jung Ju LeeAbstract:Abstract A co-cured joint, which uses excess resin extracted from the composite material (or the polymer material) as the adhesive, has several advantages compared with the adhesively bonded joint. It has no need of the surface treatment of the composite adherend and any adhesive for bonding. In addition, its manufacturing process is very simple because the bonding process is achieved during the curing process of the composite adherend. Thermal residual stresses are important in analyzing failure of the co-cured joint because composite materials are different from metal alloys in thermal and mechanical properties. In general, effects of the thermal residual stresses on failure of the adhesive joint are analyzed through experimental and analytical results. Therefore in this paper, two design parameters, namely the surface roughness of the steel adherend and the stacking sequence of the composite adherend, are considered for static and fatigue tensile tests of the co-cured single and double lap joints. Stress distribution at the interface between the two Adherends is used to analyze failure of the co-cured lap joints through the finite element method. Based on the stress distribution, two failure criteria, namely the three-dimensional Tsai–Wu failure criterion and the Ye-delamination failure criterion, are considered to predict the tensile load bearing capacity of the co-cured lap joints. Finally, effects of thermal residual stresses on failure of the co-cured single and double lap joints with the steel and composite Adherends under static and fatigue tensile load conditions are presented through comparing the experimental and analytical results.
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bond parameters to improve tensile load bearing capacities of co cured single and double lap joints with steel and carbon fiber epoxy composite Adherends
Journal of Composite Materials, 2003Co-Authors: Kum Cheol Shin, Jung Ju LeeAbstract:A co-cured joining method has several advantages over an adhesivelybonded joining method for its simple manufacturing process. It requires neither an adhesive nor surface treatment of the composite adherend and uses excess resin to bond both Adherends, including composite adherend.In this paper, the effects of bond parameters, including surface roughness on the steel adherend, stacking sequence of the composite adherend, and manufacturing pressure in the autoclave during the bonding process, on tensile load bearing capacities of plate-type co-cured single and double lap joints were investigated experimentally. Bond parameterswere related to interfacial parameterssuch asa contact area and adhesive thickness, which affected the joint strength. Experimental results were explained with respect to all of interfacial parameters and bond parameters through investigating failure surfaces of the steel adherend and a lot of data of tensile load bearing capacities. In order to predict tensile load bearing capacities...