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Anthony M Waas - One of the best experts on this subject based on the ideXlab platform.
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Corotational Formulation for Bonded Joint Finite Elements
AIAA Journal, 2014Co-Authors: Scott E. Stapleton, Anthony M Waas, Steven M. Arnold, Brett A. BednarcykAbstract:Enhanced finite elements are elements with an embedded analytical solution that can capture detailed local fields, enabling more efficient mesh independent finite element analysis. In earlier research, this method was applied to adhesively Bonded Joints. The adherends were modeled as composite Euler-Bernoulli beams, and the adhesive layer was modeled as a bed of linear shear and normal springs. The field equations were derived using the principle of minimum potential energy, and the resulting solutions for the displacement fields were used to generate shape functions and a stiffness matrix for a single Bonded Joint finite element. In this study, the capability to model large rotations and non-linear adhesive constitutive behavior is developed, and progressive failure of the adhesive is modeled by remeshing the Joint as the adhesive fails. The results obtained using this enhanced Joint element is compared with experimental results.
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a Bonded Joint finite element for a symmetric double lap Joint subjected to mechanical and thermal loads
International Journal for Numerical Methods in Engineering, 2009Co-Authors: Peter A Gustafson, Anthony M WaasAbstract:SUMMARY A Bonded Joint finite element (FE) for a symmetric double lap Joint is developed that is capable of predicting field quantities in the lap region. The element is a hybrid method and incorporates features of classical analytical and numerical methods. The element stiffness and load vector formulations have unique, load dependent, non-linear shape functions based on an analytical solution. The adaptive shape functions are formulated in terms of the dimensionless mechanical load fraction ( ¯ P) and total load ( ¯ tot) and are capable of predicting the thermal and mechanical load response. The Bonded Joint element has been implemented as a user element in the Abaqus R � commercial FE code. A comparison of the stress predictions for the Bonded Joint element and a conventional 2D FE model is presented and are found to be in good agreement. Therefore, the element provides a computationally efficient and mesh-independent stress prediction. The single element reproduces the analytical solution with minimal analyst input and can be easily incorporated into early design and sizing studies. Copyright q 2009 John Wiley & Sons, Ltd.
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a macroscopic finite element for a symmetric double lap Joint subjected to mechanical and thermal loading
48th AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference, 2007Co-Authors: Peter A Gustafson, Anthony M WaasAbstract:A thermo-mechanical analytical model and a corresponding macroscopic Bonded Joint finite element is presented for the analysis of orthotropic double lap Joints subjected to combined thermal-mechanical loads. The analytical solution offers an improvement in accuracy over its predecessor, at the cost of increased solution complexity. However, to facilitate the use of this solution, it has been incorporated into a macroscopic Bonded Joint finite element. The single element reproduces the analytical solution with minimal analyst input, and therefore can be easily incorporated into early design studies. The macroscopic element provides a computationally efficient and mesh independent comparative stress result. To validate the element, the stress predictions of the single element are compared with a continuum finite element model.
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fracture criterion for kinking cracks in a tri material adhesively Bonded Joint under mixed mode loading
Engineering Fracture Mechanics, 2005Co-Authors: De Xie, Anthony M Waas, Khaled W Shahwan, Jessica A Schroeder, Raymond G BoemanAbstract:Abstract The fracture behavior of a composite/adhesive/steel Bonded Joint was investigated by using double cantilever beam specimens. A starter crack is embedded at the steel/adhesive interface by inserting Teflon tape. The composite adherend is a random carbon fiber reinforced vinyl ester resin composite while the other adherend is cold rolled steel. The adhesive is a one-part epoxy that is heat cured. The Fernlund–Spelt mixed mode loading fixture was employed to generate five different mode mixities. Due to the dissimilar adherends, crack turning into the adhesive (or crack kinking) associated with Joint failure, was observed. The bulk fracture toughness of the adhesive was measured separately by using standard compact tension specimens. The strain energy release rates for kinking cracks at the critical loads were calculated by a commercial finite element analysis software ABAQUS in conjunction with the virtual crack closure technique. Two fracture criteria related to strain energy release rates were examined. These are (1) maximum energy release rate criterion (Gmax) and, (2) mode I facture criterion (GII = 0). They are shown to be equivalent in this study. That is, crack kinking takes place at the angle close to maximum G or GI (also minimum GII, with a value that is approximately zero). The average value of GIC obtained from bulk adhesive tests using compact tension specimens is shown to be an accurate indicator of the mode I fracture toughness of the kinking cracks within the adhesive layer. It is concluded that the crack in tri-material adhesively Bonded Joint tends to initiate into the adhesive along a path that promotes failure in pure mode I, locally.
F S K Bijlaard - One of the best experts on this subject based on the ideXlab platform.
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Analysis on Adhesively-Bonded Joints of FRP-steel Composite Bridge under Combined Loading: Arcan Test Study and Numerical Modeling
Polymers, 2016Co-Authors: Xu Jiang, Xuhong Qiang, Henk Kolstein, F S K BijlaardAbstract:The research presented in this paper is an experimental study and numerical analysis on mechanical behavior of the adhesively-Bonded Joint between FRP sandwich bridge deck and steel girder. Generally, there are three typical stress states in the adhesively-Bonded Joint: shear stress, tensile stress, and combination of both. To realize these stress states in the adhesively-Bonded Joint during tests, a specific loading device is developed with the capacity of providing six different loading angles, which are 0°(pure tension), 18°, 36°, 54°, 72° and 90°(pure shear). Failure modes of adhesively-Bonded Joints are investigated. It indicates that, for the pure shear loading, the failure mode is the cohesive failure (near the interface between the adhesive layer and the steel support) in the adhesive layer. For the pure tensile and combined loading conditions, the failure mode is the combination of fiber breaking, FRP delamination and interfacial adhesion failure between the FRP sandwich deck and the adhesive layer. The load-bearing capacities of adhesive Joints under combined loading are much lower than those of the pure tensile and pure shear loading conditions. According to the test results of six angle loading conditions, a tensile/shear failure criterion of the adhesively-Bonded Joint is obtained. By using Finite Element (FE) modeling method, linear elastic simulations are performed to characterize the stress distribution throughout the adhesively-Bonded Joint.
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experimental and numerical study on mechanical behavior of an adhesively Bonded Joint of frp steel composite bridge under shear loading
Composite Structures, 2014Co-Authors: Xu Jiang, M H Kolstein, F S K BijlaardAbstract:Abstract Due to the composite action between the Fiber-Reinforced Polymer (FRP) decks and steel girders, the deck and girder tend to bend together to carry the loading, which induce the shear stress in the adhesively-Bonded Joint between them. This paper presents an experimental and numerical study of the adhesively-Bonded Joint under shear loading. The experimental study shows that the average ultimate failure load of specimens pretreated by using sand paper and sand blasting is more than three times of that of specimens pretreated by only using acetone. Further comparison on failure modes confirms that the sufficient surface pretreatment can improve the bonding quality between the adhesive layer and the steel support. Subsequently, a three dimensional Finite Element (FE) numerical model is developed using ABAQUS 6.8. The FE analysis results are validated by experimental works, focusing on the shear deformational response of the adhesively-Bonded Joints. With the validated FE model, three-dimensional nature of the stress distribution and stress singularity at the interface between the adhesive layer and the steel support are investigated. Further study is performed on the mesh density of the FE model, to investigate the mesh dependence of stress distribution.
Peter A Gustafson - One of the best experts on this subject based on the ideXlab platform.
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a Bonded Joint finite element for a symmetric double lap Joint subjected to mechanical and thermal loads
International Journal for Numerical Methods in Engineering, 2009Co-Authors: Peter A Gustafson, Anthony M WaasAbstract:SUMMARY A Bonded Joint finite element (FE) for a symmetric double lap Joint is developed that is capable of predicting field quantities in the lap region. The element is a hybrid method and incorporates features of classical analytical and numerical methods. The element stiffness and load vector formulations have unique, load dependent, non-linear shape functions based on an analytical solution. The adaptive shape functions are formulated in terms of the dimensionless mechanical load fraction ( ¯ P) and total load ( ¯ tot) and are capable of predicting the thermal and mechanical load response. The Bonded Joint element has been implemented as a user element in the Abaqus R � commercial FE code. A comparison of the stress predictions for the Bonded Joint element and a conventional 2D FE model is presented and are found to be in good agreement. Therefore, the element provides a computationally efficient and mesh-independent stress prediction. The single element reproduces the analytical solution with minimal analyst input and can be easily incorporated into early design and sizing studies. Copyright q 2009 John Wiley & Sons, Ltd.
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a macroscopic finite element for a symmetric double lap Joint subjected to mechanical and thermal loading
48th AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference, 2007Co-Authors: Peter A Gustafson, Anthony M WaasAbstract:A thermo-mechanical analytical model and a corresponding macroscopic Bonded Joint finite element is presented for the analysis of orthotropic double lap Joints subjected to combined thermal-mechanical loads. The analytical solution offers an improvement in accuracy over its predecessor, at the cost of increased solution complexity. However, to facilitate the use of this solution, it has been incorporated into a macroscopic Bonded Joint finite element. The single element reproduces the analytical solution with minimal analyst input, and therefore can be easily incorporated into early design studies. The macroscopic element provides a computationally efficient and mesh independent comparative stress result. To validate the element, the stress predictions of the single element are compared with a continuum finite element model.
Wang Juan - One of the best experts on this subject based on the ideXlab platform.
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Microstructure and properties near interface zone of diffusion-Bonded Joint for Mg/Al dissimilar materials
Transactions of the China Welding Institution, 2007Co-Authors: Wang JuanAbstract:The interface zone of Mg/Al diffusion-Bonded Joint is constituted with Al transition layer(Mg2Al3 phase),middle diffusion layer(MgAl phase) and Mg transition layer(Mg3Al2 phase).Some diffusion holes exist between the Al transition layer and middle diffusion layer observed by SEM.It is unfavorable to obtain diffusion-Bonded Joint of good performance.With the increase of heating temperature,the shear strength of Joint interface shows the trend of increasing firstly and then decreasing.The highest shear strength is about 18.94 MPa when the heating temperature is 475 ℃,holding time is 60 min and pressure is 0.081 MPa.The microhardness test indicated that the microhardness of diffusion zone is about 260-350 HM.However,and the diffusion zone exist three different hardness regions.With the increase of heating temperature,the microhardness and diffusion width of interface diffusion zone increase gradually.
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investigation of interfacial structure of mg al vacuum diffusion Bonded Joint
Vacuum, 2006Co-Authors: Liu Peng, Li Yajiang, Geng Haoran, Wang JuanAbstract:Abstract The interfacial structure of the Mg/Al diffusion-Bonded Joint was studied by means of SEM, EPMA and TEM. The test results indicated that the interface zone of Mg/Al diffusion-Bonded Joint included the transition region on Mg side, the mid-diffusion region and the transition region on Al side. The concentration distribution of Mg and Al atoms in the diffusion zone includes three different regions. The three regions are intermetallic compounds Mg 2 Al 3 , Mg 3 Al 2 and MgAl, respectively. The location of Mg 2 Al 3 , Mg 3 Al 2 and MgAl phases in the diffusion zone can be determined. The Mg 3 Al 2 phases were observed in the transition region on Mg side by means of TEM.
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a study of phase constitution near the interface of mg al vacuum diffusion bonding
Materials Letters, 2005Co-Authors: Liu Peng, Li Yajiang, Geng Haoran, Wang JuanAbstract:Abstract The characteristics of phase constitution near the interface of Mg/Al diffusion Bonded Joint are studied by means of scanning electron microscope (SEM), X-ray diffraction (XRD) and transmission electron microscope (TEM). The test results indicated that the obvious diffusion zone forms near the Mg/Al interface as a result of the vacuum diffusion bonding. The diffusion zone of Mg/Al diffusion Bonded Joint consists of intermetallic compounds MgAl, Mg3Al2 and Mg2Al3. The transition region on Mg side mainly consists of Mg crystals, and the new phase formed is Mg3Al2 intermetallic compounds. This is favorable to the enhancing of the combination strength for Mg substrate/diffusion zone.
Soon Hyung Hong - One of the best experts on this subject based on the ideXlab platform.
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Microstructure and bonding mechanism of Al/Ti Bonded Joint using Al–10Si–1Mg filler metal
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2003Co-Authors: Woong H. Sohn, Ha H. Bong, Soon Hyung HongAbstract:Abstract The microstructures and liquid state diffusion bonding mechanism of cp-Ti to 1050 Al using an Al–10.0wt.%Si–1.0wt.%Mg filler metal with 100 μm in thickness have been investigated at 620 °C under 1×10−4 Torr. The effects of bonding process parameters on microstructure of Bonded Joint have been analyzed by using an optical microscope, AES, scanning electron microscopy and EDS. The interfacial bond strength of Al/Ti Bonded Joints was measured by the single lap shear test. The results show that the bonding at the interface between Al and filler metal proceeds by wetting the Al with molten filler metal, and followed by removal of oxide layer on surface of Al. The interface between Al and filler metal moved during the isothermal solidification of filler metal by the diffusion of Si from filler metal into Al layer. The interface between Al and filler metal became curved in shape with increasing bonding time due to capillary force at grain boundaries. The bonding at the interface between Ti and filler metal proceeds by the formation of two different intermetallic compound layers, identified as Al5Si12Ti7 and Al12Si3Ti5, followed by the growth of the intermetallic compound layers. The interfacial bond strength at Al/Ti Joint increased with increasing bonding time up to 25 min at 620 °C. However, the interfacial bond strength of Al/Ti Joint decreased after bonding time of 25 min at 620 °C due to formation of cavities in Al near Al/intermetallic interfaces.
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microstructure and bonding mechanism of al ti Bonded Joint using al 10si 1mg filler metal
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2003Co-Authors: Woong H. Sohn, Ha H. Bong, Soon Hyung HongAbstract:Abstract The microstructures and liquid state diffusion bonding mechanism of cp-Ti to 1050 Al using an Al–10.0wt.%Si–1.0wt.%Mg filler metal with 100 μm in thickness have been investigated at 620 °C under 1×10−4 Torr. The effects of bonding process parameters on microstructure of Bonded Joint have been analyzed by using an optical microscope, AES, scanning electron microscopy and EDS. The interfacial bond strength of Al/Ti Bonded Joints was measured by the single lap shear test. The results show that the bonding at the interface between Al and filler metal proceeds by wetting the Al with molten filler metal, and followed by removal of oxide layer on surface of Al. The interface between Al and filler metal moved during the isothermal solidification of filler metal by the diffusion of Si from filler metal into Al layer. The interface between Al and filler metal became curved in shape with increasing bonding time due to capillary force at grain boundaries. The bonding at the interface between Ti and filler metal proceeds by the formation of two different intermetallic compound layers, identified as Al5Si12Ti7 and Al12Si3Ti5, followed by the growth of the intermetallic compound layers. The interfacial bond strength at Al/Ti Joint increased with increasing bonding time up to 25 min at 620 °C. However, the interfacial bond strength of Al/Ti Joint decreased after bonding time of 25 min at 620 °C due to formation of cavities in Al near Al/intermetallic interfaces.
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Microstructure and bonding mechanism of Al/Ti Bonded Joint using
2003Co-Authors: Woong H. Sohn, Ha H. Bong, Soon Hyung HongAbstract:The microstructures and liquid state diffusion bonding mechanism of cp-Ti to 1050 Al using an Al � /10.0wt.%Si � /1.0wt.%Mg filler metal with 100 mm in thickness have been investigated at 620 8C under 1 � /10 � 4 Torr. The effects of bonding process parameters on microstructure of Bonded Joint have been analyzed by using an optical microscope, AES, scanning electron microscopy and EDS. The interfacial bond strength of Al/Ti Bonded Joints was measured by the single lap shear test. The results show that the bonding at the interface between Al and filler metal proceeds by wetting the Al with molten filler metal, and followed by removal of oxide layer on surface of Al. The interface between Al and filler metal moved during the isothermal solidification of filler metal by the diffusion of Si from filler metal into Al layer. The interface between Al and filler metal became curved in shape with increasing bonding time due to capillary force at grain boundaries. The bonding at the interface between Ti and filler metal proceeds by the formation of two different intermetallic compound layers, identified as Al5Si12Ti7 and Al12Si3Ti5, followed by the growth of the intermetallic compound layers. The interfacial bond strength at Al/Ti Joint increased with increasing bonding time up to 25 min at 620 8C. However, the interfacial bond strength of Al/Ti Joint decreased after bonding time of 25 min at 620 8C due to formation of cavities in Al near Al/intermetallic interfaces. # 2003 Elsevier Science B.V. All rights reserved.