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In this study, three different size (100-300-500 µm) of the rubber powder (waste tire) were used in the formulation of epoxy- phenolic adhesive. Rubber powder was modified with grafting method by acrylamide monomer. In order to prevent any loss in properties such as modulus and strength of the adhesive, which is due to the addition of rubber powder to the adhesive, the micro particles of silica were used in formulation of epoxy- phenolic adhesive.  The experiment was designed by Taguchi method, and in the experiment, the effect of the composition of rubber powder, size of rubber powder, composition of silica filler and phenolic resin on mechanical and thermal properties of epoxy adhesives were investigated. To study the mechanical properties of adhesives and adhesion properties, dumbbell-shaped specimens and single edge lap bonds that have been made of metal (stainless steel) to composite (epoxy resin / carbon fiber) were prepared and subjected to tensile test. Thermal stability and interfacial interaction between epoxy and filler in adhesive formulation were explored by thermogravimetric analysis and Fourier transform infrared spectroscopy analyses, respectively.  Tensile test results showed that for lap- joint bonding with the addition of each factor in its optimal level into epoxy adhesive, strength, modulus and toughness increase by 7.5%, 27.56% and 114% respectively in comparison with  the samples bonded with the neat  epoxy adhesive. A significant increase was obtained in thermal stability for formulated adhesive samples compared with neat epoxy adhesive.
 
 

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The aim of this project is the design and optimization of the formulation of epoxy adhesives for bonding metal to composite parts . This joints are most widely used in the aerospace industry to reduce stress concentration at a point. Joints for single edge joining include stainless steel metal with commercial code 316L and composite epoxy resin / carbon fiber. In this study, the effect of three types of additives: filler (alumina micro-particles), nylon 6.6 and phenolic resin (type of resin) on the mechanical and thermal properties of epoxy adhesive have been investigated. Tensile test results showed that increasing alumina fillers increases the tensile strength and overlap shear adhesive samples, respectively, in single lap joint dumbbells and elderly. The test showed that increasing the amount of nylon 6.6 When is slightly higher due to a sharp drop in tensile strength and overlap shear, respectively, in both cases is dog bone and single lap joint adhesives. This limit depends on the capacity epoxy ring to absorb amide hydrogens. The test for thermal properties (TGA) showed that increasing the amount of phenolic thermal stability is improved. High-temperature tensile test of appropriateness is also increasing impact of phenolic resin. Finally, the adhesive properties built with the similar adhesive (UHU) were compared. Results showed superiority in single lap joint metal to composite adhesive is made in the study.

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Inconel 625 is a nickel-base supper alloy that is widely used in power plants industry, aerospace systems, and mineral industries due to its properties such as high tensile strength, high corrosion resistance and excellent fabricability. Resistance spot welding (RSW) is one of the important joining processes for assembling supper alloy sheets, because of accuracy and high production rates. In the present research, the influences of electrode tip diameter and other RSW parameters on distribution of temperature and nugget formation are investigated by the finite element method for Inconel 625 superalloy. The process is simulated with a 2D axisymmetric coupled electro-thermal and uncoupled mechanical finite element model by using ABAQUS software package. In order to improve accuracy of simulation, material properties including physical, thermal and mechanical properties is supposed to be temperature-dependent. The diameter of computed weld nuggets is compared with experimental results and good agreement is observed. So, FE model developed in this paper provides prediction of quality and shape of the weld nuggets and temperature distributions with variation of each process parameter, suitably. The results show that increasing electrode tip diameter decreases weld nugget diameter, in constant welding current, but in general, the electrode tip diameter cannot be selected less than a distinct value.