Improvement of weld quality in electromagnetic welding of aluminum-stainless steel sheets

In this paper, the electromagnetic welding of two dissimilar metals was simulated using LS-Dyna software. Results of finite element simulations were used to obtain a high quality weld between the aluminum and stainless steel by the minimum discharge energy. The experiments were designed according to a Box-Behnken response surface methodology to extract the regression models from the significant parameters of voltage, standoff distance and thickness of driver. Possibility of weld formation were predicted by using the weldability window of aluminum-stainless steel. According to the results of analysis of variance, the quality of weld can be improved by applying the following values of parameters: voltage of 15 kV, standoff distance of 1.5 mm and driver thickness of 1 mm. The results of the finite element simulations were confirmed by conducting the electromagnetic welding at the optimal condition of parameters. In order to evaluate the quality of joints, the microstructure of weld interface was studied using the optical and scanning electron microscope.     

Analysis of tribological behaviour of aluminum-titanium carbide-basalt metal matrix composite

In the recent years, particulate reinforced aluminum based matrix composites are playing an important role in automobile and aerospace applications due to their enhanced properties. In this work, an attempt has been made to optimize the tribological behaviour of aluminum 7075 matrix reinforced with titanium carbide (3 percent weight) and basalt particles (2 percent weight) using Taguchi based grey relational analysis. Composites are fabricated according to american society for testing materials standard using stir casting method dry sliding wear tests were carried out using pin on disc apparatus as per Taguchi's L9 orthogonal array. Grey relational analysis was used to obtain the optimum process parameters for multiple quality characteristics such as wear rate and coefficient of friction. Then significant contribution of wear parameters was determined by analysis of variance. A confirmatory test was carried out to validate the test result. Finally, the micro structural investigation on the worn surfaces was performed by scanning electron microscope.     

Studies on fly ash/coir/sugarcane reinforced epoxy polymer matrix composite

In the past years studies were conducted on natural fibre reinforced polymer composites to observe their mechanical properties in order to decide their industrial applications. These composites have already been used in many applications from aerospace to sporting equipment. These green composites can be used as a replacement for synthetic composites. This is because the natural fibres are eco-friendly, biodegradable, renewable, etc. In this work, an attempt is made to reinforce fly ash, coir fibre and sugarcane fibre with epoxy polymer matrix. Central composite design under response surface methodology (RSM), one of the approaches of design of experiments (DOE) is used to determine optimum sample preparation conditions of fly ash, coir fibre and sugarcane fibre. Both tensile and flexural (three-point bending) tests are conducted on these fabricated composites to determine their materialistic characteristics. Analysis of variance (ANOVA) is carried out using Minitab software to find the influence of fly ash, coir fibre, sugarcane fibre on composites. Regression equations obtained from analysis of variance is used to calculate values. Experimental and calculated values are compared and their error % are calculated and tabulated. Response surface optimization study is carried to find the optimized parameters of composites. It is observed that, increase in wt.% of coir fibre and decrease in wt.% of fly ash and sugarcane fibre, increases yield stress and these parameters have mixed impact on ultimate tensile stress. The addition of fly ash, coir fibre and sugarcane fibre in low percentages increases Young's modulus. Increase in wt.% of fly ash and coir fibre and decrease in wt.% of sugarcane, increases flexural modulus and flexural stress.     

Optimization of dry sliding wear behaviour of industrial wastes reinforced aluminium based metal matrix composites

Marble dust and basalt powder are industrial waste generated during the machining of marble stone and basalt rock. This paper presents an approach for the optimization of dry sliding wear parameters of aluminium 7075 reinforced with marble dust and basalt powder hybrid metal matrix composite using Taguchi based grey relational analysis. In this work, the composite is fabricated by stir casting technique and the wear parameters namely load, sliding velocity and sliding distance are optimized with consideration of multi responses such as wear rate and coefficient of friction. Experiments are conducted as per Taguchi's L9 orthogonal array. A grey relational analysis is carried out and grey relational grade is obtained. Based on the grey relational grade, optimum level of wear parameters has been identified by analysis of variance. The test results are validated by conducting the confirmation test. Experimental results have shown that the sliding velocity is the most effective factor among the control parameters on dry sliding wear, followed by the sliding distance and load. Finally, the micro structural investigations on the worn surfaces are performed by scanning electron microscope.     

Testing and modeling for the tensile strength of nylon badminton string at different processing conditions

Nylon is a thermoplastic engineering material widely used in several applications. But to increase the application of nylon in sports, the focus of this work was to optimize the tensile strength of nylon for badminton string. In particular, the testing conditions (temperature, relative humidity and tensile rate) were investigated. The results obtained showed that increasing the processing temperature and humidity both had a negative effect on tensile strength, while increasing the tensile rate had a positive effect. Then, a mathematical model to predict the tensile strength was established by using a response surface methodology and the optimal conditions were verified to validate the parameters. Furthermore, an analysis of variance was used to determine the significant effect of each term on the final response. Based on the results obtained, it was found that the optimum processing temperature is 2.9 °C with a relative humidity of 0 % when the tensile rate is 60 mm/min.