A Coupled Shear Stress-Diffusion Model for Adhesively Bonded Single Lap Joints

Author(s):  
Sayed A. Nassar ◽  
Emad Mazhari

In this study, a coupled shear stress-diffusion model is developed for the analysis of adhesively bonded single lap joints by applying Fickian diffusion model to the adhesive layer. Differential equations of equilibrium are formulated in terms of adhesive material properties that are time and location-dependent. By invoking a Volkersen approach on the equilibrium equations, a shear stress differential equation is formulated, and numerically solved. Several scenarios are considered for investigating the effect of diffusion on shear stress distribution in adhesively bonded single lap joints. Detailed discussion of the results is presented.

2016 ◽  
Vol 83 (10) ◽  
Author(s):  
Sayed A. Nassar ◽  
Emad Mazhari

In this study, a coupled shear stress-diffusion model is developed for the analysis of adhesively bonded single lap joints (SLJs) by applying Fickian diffusion model to the adhesive layer. Differential equations of equilibrium are formulated in terms of adhesive material properties that are time and location dependent. By invoking a Volkersen approach on the equilibrium equations, a shear stress differential equation is formulated and numerically solved. Several scenarios are considered for investigating the effect of diffusion on shear stress distribution in adhesively bonded SLJs. Detailed discussion of the results is presented.


Author(s):  
Emad Mazhari ◽  
Sayed A. Nassar

In this study, the Fickian diffusion formulation is extended to the adhesive layer of a single lap joint (SLJ) model, in order to develop a coupled peel and shear stress-diffusion model. Constitutive equations are formulated for shear and peel stresses in terms of adhesive material properties that are time- and location-dependent. Numerical solution is provided for the effect of diffusion on shear and peel stresses distribution. Detailed discussion of the results is presented.


Author(s):  
Emad Mazhari ◽  
Sayed A. Nassar

In this study, the Fickian diffusion formulation is extended to the adhesive layer of a single lap joint model, in order to develop a coupled peel and shear stress-diffusion model. Constitutive equation are formulated for shear and peel stresses in terms of adhesive material properties that are time and location-dependent. Numerical solution is provided for the effect of diffusion on shear and peel stresses distribution. Detailed discussion of the results is presented.


2014 ◽  
Vol 912-914 ◽  
pp. 441-444
Author(s):  
Yan Rong Pang ◽  
Ran Liu ◽  
Ya Juan Li ◽  
Bo Han Lu ◽  
Xin Kang Xing ◽  
...  

Acoustic emission (AE) was used to monitor the tensile test of composites with adhesive specimens. The mechanical response behavior, damage and failure characteristics, and the corresponding AE characteristics of the composites have been investigated. The results show that the load of the join with defect in the adhesive layer is lower than the join with no defect. The higher AE relative energy and the AE amplitude were obtained in the adhesive specimen with defect in the adhesive layer whereas the variation of the AE relative energy is different from the adhesive specimen with on defect. The characteristics such as AE amplitude distribution, relative energy and cumulative hits are connected with the tensile damage and failure of the adhesively bonded single-lap joints of composite laminate. In the actual AE monitoring, these feature parameters should be considered entirely assess the damage and failure of the composites structures.


2017 ◽  
Vol 754 ◽  
pp. 252-255
Author(s):  
S.M.J. Razavi ◽  
F. Berto

In the current paper, the geometric and material parameters of metal fibers utilized for strengthening adhesively bonded single lap joints under flexural loading were investigated by using experimental investigations. According to the test results, incorporating metal fibers in the adhesive layer of a bonded joint can have a significant impact on the flexural load bearing of the joint. The distance between the fibers and also the fibers orientation were considered as the key parameters in this research. It was concluded that the load bearing of the joint can be improved by reducing the distance between the fibers and the highest failure loads were obtained for the joints reinforced by fibers in the longitudinal direction.


1998 ◽  
Vol 33 (5) ◽  
pp. 331-346 ◽  
Author(s):  
C H Wang ◽  
M Heller ◽  
L R F Rose

A method based on the successive boundary stress correction approach is presented for the determination of the stress concentration in substrates of adhesively bonded joints with square edges or spew fillets at the ends of the overlap. The emphasis is given to developing an estimate of the stress elevation at the end of a bonded joint while the issue of corner singularity at the substrate-adhesive interface is not addressed in detail. It is shown that the adhesive shear stress which acts on the substrates is the main cause of the stress concentration; the adhesive peel stress has little effect. To circumvent the deficiencies of existing bonded joint theories which generally predict a maximum adhesive shear stress at the ends of the adhesive layer, an eigenfunction solution has been derived for the shear stress distribution near the ends of the overlap. Based on the improved adhesive shear stress solution presented here, the stress concentration determined from the present theory is found to be in good agreement with finite element results.


2010 ◽  
Vol 139-141 ◽  
pp. 986-989 ◽  
Author(s):  
Hai Long Zhao ◽  
Zong Zhan Gao ◽  
Zhu Feng Yue ◽  
Zhi Feng Jiang

The stress distribution of adhesively-bonded single lap joints under tensile shear loading is analyzed using 2-dimensional elastic-plastic finite element method (FEM). Special attentions have been put on the influence of void in adhesive on the stress distribution of adhesively-bonded joints. The results show that the stress concentration of the void is less than that of the end part of the joints when adhesive layer’s deformation was in the range of elastic. Moreover, the influence of the void on the stress distribution becomes less when the void moving from the end-part to the middle. The stress concentration becomes larger and the stress distribution of adhesive’s mid-thickness region becomes flatter when adhesive layer has biggish plastic deformation. Finite element results show an agreement with the theoretical results.


2011 ◽  
Vol 181-182 ◽  
pp. 814-819 ◽  
Author(s):  
Yan Yan Ma ◽  
Kai Fu Zhang ◽  
Zhao Jun Yang ◽  
Yuan Li

A parametric study on CFRP/Al adhesively bonded single lap joints was experimentally conducted. The primary objective of this study is to investigate the effects of overlap length and impact loads on the failure mode and failure load of joints. Experimental results show that structural failure of joints occurred in the adhesive layer or the bonded interface; failure loads and impact resistance of the joint increased as the overlap length increased; the carrying load of joints which subjected to impact declined significantly because of internal damage of the adhesive layer.


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