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Bond behaviour of CFRP-steel double-lap shear joints exposed to marine atmosphere
Published in Nigel Powers, Dan M. Frangopol, Riadh Al-Mahaidi, Colin Caprani, Maintenance, Safety, Risk, Management and Life-Cycle Performance of Bridges, 2018
Q.Q. Yu, R.X. Gao, X.L. Gu, X.L. Zhao
To the best knowledge of the authors, there have been limited attempts to perform an experimental study exposed to salt fog to simulate the marine atmosphere which is frequently occurred to steel cross-sea bridges. According to manufactures’ datasheet, the structural adhesive Araldite 420 A/B gels in three to four hours at 25 °C and is sufficiently cured to allow handling after 5 hours. 90% of the full strength could be achieved by four to five days and the full strength development takes one to two weeks at room temperature. Currently, the aforementioned research generally first cured the specimens at room condition and then exposed them to aggressive conditions. The effect of environmental exposure during the curing stage of adhesive hasn’t been well understood.
Basic Design of Ultrasonic Transducers
Published in Dale Ensminger, Leonard J. Bond, Ultrasonics, 2011
Dale Ensminger, Leonard J. Bond
Various materials have high absorption characteristics and are suitable for damping purposes. Suitable mixtures can be formulated with graphite, powdered metals, and metaloxides of random grain sizes either fuzed or adhesively bonded together. Suitable adhesives and bonding materials include Araldite and epoxy cements.
Cohesive Zone Modelling for Static Applications
Published in Raul D.S.G. Campilho, Strength Prediction of Adhesively-Bonded Joints, 2017
Unidirectional carbon-epoxy pre -preg (SEAL® Texipreg HS 160 RM) with 0.15 mm thickness was considered for the composite adherends of the single-lap joints, with the [0]16 lay- up. Table 6.1 presents the elastic properties of a unidirectional lamina, modelled as elastic orthotropic in the FEM analysis (Campilho et al. 2005). Two epoxy adhesives were considered. The adhesive Araldite® AV138 is a two-part (resin + hardener) brittle and high strength adhesive suited to bond a large variety of materials such as metals or polymers/polymer composites. The adhesive Araldite® 2015 is equally a two-part structural adhesive, showing a smaller ultimate strength than the previous one, but allowing large plastic flow prior to failure, which is an important feature for bonded joints, as it allows redistribution of stresses at stress concentration regions, which usually takes place because of the sharp edges at the overlap ends and also joint asymmetry/distinct deformation of the adherends along the overlap. The adhesives were previously characterized regarding E, G, the failure strengths in tension and shear (corresponding to tn0 $ t_{\text{n}}^{0} $ and ts0 $ t_{\text{s}}^{0} $ ) and the values of GIc and GIIc. For the characterization of the mechanical properties, bulk tests were performed to characterize the adhesives in tension, and TAST were chosen for shear characterization. It should be pointed out that the cohesive strengths of thin adhesive layers and the bulk strengths of adhesives are different quantities (Ji et al. 2010). This is because bulk adhesives are homogeneous materials cracking perpendicularly to the maximum principal stress direction, while adhesives as thin layers are highly constrained between stiff adherends, and damage growth under these conditions occurs under mixed-mode (tension plus shear) and along the predefined path of the bonding direction. In this case study, the cohesive strengths of the adhesives were assumed as equal to their bulk quantities as an approximation. The good correspondence that was observed by the comparisons to the experimental data allowed the assumption that a fair approximation was attained, and corroboration of the use of these properties.
Experimental study on failure mechanism of CFRP-to-aluminium single-lap adhesive joints under tension after out-of-plane pre-impact
Published in The Journal of Adhesion, 2023
Tianchun Zou, Ji Fu, Yuezhang Ju
The adherends surfaces were treated before the manufacturing process to improve bonding strength. The bonding surface of aluminium substrates and laminates were polished with waterproof abrasive papers (80 meshes). The abrasion should be used carefully to avoid breaking the fibre completeness. Acetone was subsequently used to remove the detritus and oil contamination. Araldite 2015 adhesive was evenly applied on the bonding surface of adherends. In order to set the thickness of the adhesive layer, 2 mm adherend spacers and 0.2 mm calibration spacers (stainless steel plate) were used to obtain an adhesive thickness of 0.2 mm. After fixed spacers, the joints were clamped by clips for continuous pressure. Figure 2 shows the configuration for single-lap joint fabrication. Due to the large dispersion of composite properties, each test was repeated four times to ensure the repeatability and effectiveness of test results.
Research on the Aging Effects of Adhesive and Composites on the Degradation Mechanism of Composite Adhesive Joints in Thermal-Humidity-Cycles for Automobiles
Published in The Journal of Adhesion, 2023
Guofeng Qin, Yunli Zhang, Peiwen Mi, Yongjian Zhu, Ming Li, Jingxin Na
The performance of Araldite® 2015 plays an important role in the joint strength of adhesive joints. Bulk specimens fabricated according to NF ISO527-2 standards were used to study the performance of adhesive in this paper. The cross-sectional dimension of the tested area of bulk specimens is 10 × 2 mm2 and the two-dimensional diagram is presented in Figure 1. To process a standard bulk specimen, a set of bulk specimen mold was designed, as presented in Figure 2. It was machined from stainless steel with high assembly accuracy and consisted of three main parts: the base, the forming chamber and the cover, which can simultaneously finish the processing of 5 bulk specimens and improve the consistency of bulk specimens. The entire process was completed in a sealed environment of 25 ± 2°C/50% RH. The adhesive was cured at room temperature for 24 hours after being injected into the mold. Next, once the adhesive was initially cured, it was disassembled from the mold and cured at 80°C for two hours to complete the manufacturing process.
Experimental and numerical assessment of the effect of transverse reinforcing of AL-GFRP single lap adhesive joint using Z-pins under tensile loading
Published in The Journal of Adhesion, 2022
A. Mirzaei, A.H. Darbandi, M. Ramzaninezhad, M. Rezvaninasab, M. H. Alaei
After the preparation of the adherends, the Araldite 2015 adhesive was prepared by mixing the two components A/B in the ratio of 1:1. After blending the A and B parts, the paste was applied to the two adherends using a thickness control fixture shown in Figure 2. Four accurate spacers provided the required thickness of the adhesive (0.2 mm uniform thickness), and several circular baffles were used to avoid adherend rotation in this fixture. According to the material data sheet, the assembled joints were finally cured (rising the temperature to 90°C in 1 h and holding at 90°C for 1 hour).