Effect of Alkali on the Impact Toughness of Adhesively Bonded Joints

2012 ◽  
Vol 166-169 ◽  
pp. 1904-1907
Author(s):  
Min You ◽  
Chun Zhi Mei ◽  
Wen Jun Liu ◽  
Jing Rong Hu ◽  
Ling Wu

The effect of the temperature and immersed time of the alkali solution on the impact toughness of the adhesively bonded steel single lap joint under impact loading is studied using the experimental method. The results obtained show that the impact toughness of the specimen increased when the immersed time increased then it decreased as it beyond 3 days. When the immersed time is longer than 72 h, the higher the temperature is, the lower the impact toughness of the joint. The moisture absorption of the adhesive layer with the immersed time was also investigated and it was found that there is a relationship to the impact toughness of the adhesively bonded single lap joint. The epoxy adhesive layer was analyzed with FT-IR and it was found that the hydroxyl enhanced and bonding strength may increase after 72 h immersed in alkali solution.

2011 ◽  
Vol 230-232 ◽  
pp. 1350-1354 ◽  
Author(s):  
Min You ◽  
Jing Rong Hu ◽  
Xiao Ling Zheng ◽  
Ai Ping He ◽  
Cun Jun Chen

The effect of the adhesive thickness on the impact toughness of the adhesively bonded steel joint under impact loading is studied using the experimental method. The results obtained show that the impact toughness increases when the adhesive thickness increased then it decrease as the adhesive thickness increase. When the curing time is set as a constant, the higher the curing temperature is, the lower the impact toughness of the joint. The optimum thickness of the adhesive layer for the specimen of impact toughness test cured at 60 C for 1 h is 0.6 mm and it is 0.4 mm to 0.6 mm for the specimen cured 1 h at temperature of 90 C or higher than it. It is recommended using the notched specimen to decrease the testing deviation.


1981 ◽  
Vol 48 (2) ◽  
pp. 331-338 ◽  
Author(s):  
F. Delale ◽  
F. Erdogan

In this paper an adhesively bonded lap joint is analyzed by assuming that the adherends are elastic and the adhesive is linearly viscoelastic. After formulating the general problem a specific example for two identical adherends bonded through a three parameter viscoelastic solid adhesive is considered. The standard Laplace transform technique is used to solve the problem. The stress distribution in the adhesive layer is calculated for three different external loads namely, membrane loading, bending, and transverse shear loading. The results indicate that the peak value of the normal stress in the adhesive is not only consistently higher than the corresponding shear stress but also decays slower.


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.


2005 ◽  
Vol 13 (4) ◽  
pp. 359-370 ◽  
Author(s):  
Makoto Imanaka ◽  
Makoto Taniguchi ◽  
Tatuyuki Hamano ◽  
Masaki Kimoto

An estimation method of fatigue strength of adhesively bonded joints with various stress triaxialities in the adhesive layer has been proposed based on a damage evolution model for high cycle fatigue. To realize various triaxial stress states, fatigue test was conducted for adhesively bonded butt and scarf joints with various scarf angles bonded by a rubber-modified epoxy adhesive. An equation for estimating the damage evolution in the adhesive layer of the butt and scarf joints was derived from the damage model, where undefined parameters in the equation were determined by comparing the experimentally obtained damage evolution curves of the butt joints with the estimated damage evolution curves. Furthermore, an equation for the estimation of fatigue strength was derived under the assumption that fatigue failure occurs when the damage variable reaches to a critical value. When compared the experimental S-N data of scarf joints with the estimated ones, the estimated fatigue strengths agree well with the experimental data with various scarf angles. This finding suggests that the CDM model is applicable for estimating fatigue strength of adhesively bonded joints with different stress triaxialities.


Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 330
Author(s):  
Marta Kałuża ◽  
Jacek Hulimka ◽  
Arkadiusz Bula

The use of adhesive to joint structural elements, despite many advantages of this technology, is not a method commonly used in engineering practice, especially in construction. This is mainly due to the poor recognition of the behavior, both in terms of testing and analysis, of joints made on a scale similar to the actual elements of building structures. Therefore, this paper presents the results of model tests and then numerical analyses of adhesively bonded joints made of high-strength steel elements in a full-scale (double-lap joint). In order to properly model the adhesive connection, material tests of the methacrylate adhesive were performed in the field of tensile, shear (in two versions: single lap joint test and thick adherent shear test) and bond properties. Comparison of the results of the model and numerical tests showed very good agreement in terms of the measurable values, which makes it possible to consider the results obtained in the adhesive layer as reliable (not directly measurable in model tests). In particular, the distribution of stresses inside the adhesive layer, the range of plastic zones and areas of loss of adhesion are presented and discussed. The results indicate the possibility of a reliable representation of the behavior of adhesively bonded joints of high-strength steel, thus providing a tool for the analysis of semirigid adhesive in large-size joints.


1992 ◽  
Vol 114 (3) ◽  
pp. 344-352 ◽  
Author(s):  
S. Tanary ◽  
Y. M. Haddad ◽  
A. Fahr ◽  
S. Lee

This paper is concerned with the use of the acousto-ultrasonic technique to evaluate nondestructively the mechanical performance of composite bonded joints. In this context, acousto-ultrasonic measurements followed by destructive shear tests were performed on single lap joint specimens made from graphite/epoxy adherends joined with FM 300 film adhesive. The results indicate a good correlation between acousto-ultransonic wave propagation characteristics and the shear strength of the bonded joints under different testing conditions. These correlations suggest that an estimation of the joint strength can be made by using acousto-ultrasonics provided that the measurement system is calibrated for variations of the material and geometry of the specimen.


2007 ◽  
Vol 348-349 ◽  
pp. 273-276 ◽  
Author(s):  
Min You ◽  
Shan Yu ◽  
Hai Zhou Yu ◽  
Zhi Li ◽  
Wen Jun Liu

The effect of the preformed deflection angle in the lap zone on the failure mode and the stresses distribution in the single-lap joint made of the epoxy adhesive and the aluminium adherend was investigated using elasto-plastic finite element method (FEM) and the experimental method of the shear strength testing. The failed surfaces were studied with the diagrams of scanning electron microscopy (SEM). The results from the numerical simulation showed that all the peak stresses in adhesively bonded single lap joint were decreased first and increased again as the preformed deflection angle was increased from 00 to 150. The lowest values occurred when the angle was taken as 100 and its strength is 22.1% higher than that of the standard one as the peak stresses were decreased and the stress distributed more evenly. The SEM images also show that the failure mode of the joint was transmitted from the adhesion to the mixed one as the deflection angle increased.


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.


2018 ◽  
Vol 53 (23) ◽  
pp. 3335-3346 ◽  
Author(s):  
Hamid Reza Borghei ◽  
Bashir Behjat ◽  
Mojtaba Yazdani

In this paper, the effect of graphene nanoparticle additive on the strength of simple and hybrid (rivet-bonded) single-lap joints is studied using the experimental method. Two different types of graphene with different number of layer and thicknesses are used in adhesive-graphene nanoparticle composite construction. At first, tensile tests are done on bulk specimens of adhesive with different additives. It is found that adding 0.5 wt% of graphene to the neat adhesive leads to an increase in the ultimate tensile strength of bulk specimens almost 24% and 12% for two graphene types compared to the neat adhesive. Also, the shear strength of adhesive and hybrid lap joints incorporating two types of graphene nanoparticles (types I and II) is compared to that of adhesive and hybrid joints without graphene nanoparticles. SEM results of fracture surfaces show that the inclusion of graphene nanoparticle to the adhesive increases the roughness of surfaces. Experimental results reveal that graphene nanoparticle increases the strength of bonded and hybrid joints. It is observed that, graphene with a lower thickness and number of layers has a better influence on joint strength. In fact, graphene nanoparticle type II makes a homogeneous distribution in adhesive-graphene nanoparticle composite and causes a significant increase on joint strength.


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