Experimental Study on Optimization of Filler Concentration of Silicon Rubber Compound Used in High Voltage Insulators

In any power transmission system, insulators are essential for a reliable electrical power supply. The Efficiency of insulators will be decided by their electrical and mechanical properties. Recently in many of the power transmission systems, the conventional porcelain insulators are being replaced by polymeric insulators due to various advantages in their properties. Polymeric insulators have been increasingly popular in recent years as a result of their superior performance in contaminated environments due to their hydrophobic nature. However, research is still being carried out on Polymeric material with regards to ageing condition and feasibility for large scale utilization. Ageing of insulation is due to Environmental, Tracking and Erosion conditions. Ageing leads to immature failures and uncertainty in the performance of the insulators. The constituent materials and their properties have a significant impact on the performance of polymeric insulators. There is a strong need to look into newer filler materials which can be added to the existing polymeric base materials to constitute a composite. Keeping this in mind, in the proposed research uses Silicone rubber as base polymeric material and along with that additives are added to arrive at three different composites. A new filler material will be added to the base material forming a new composite. All these HTV Silicone rubber based composites are then tested the recovery of hydrophobicity, dielectric strength, hardness, specific gravity, tensile strength , ultimate elongation ,tear strength properties based on ASTM standards. Further, Inclined plane Tracking and Erosion studies are also conducted on the polymeric test samples for 6 hours to evaluate the SiR housing material suitability for outdoor insulator applications by subjecting them to AC high voltages under laboratory conditions as per IEC 60587 standards. Keywords: Recovery of hydrophobicity, dielectric strength, hardness, specific gravity, tensile strength, ultimate elongation, tear strength, inclined plane tracking and erosion, ageing, filler material.

Delamination ASSESSMENT during MACHINING OF laminated POLYMER nanocomposite

Nanomaterials are gaining extensive application in the manufacturing sector due to favorable properties. Its rapid growth in highly sensitive, robust, and lightweight sensors and biomedical components has attracted considerable attention worldwide. Nanomaterial uses with fiber-reinforced polymeric material have increased significantly. In order to manufacture structural components in a near-net shape, laminated nanocomposite machining is required. Due to the need for product assembly in mechanical structures, Milling is the primarily machining process in the manufacturing industry to create slots, channels, etc. The present work optimized the process variables affecting the Milling process by adopting the minimize criterion to control the delamination factor using the Taguchi method. The process parameters include cutting speed, feed, depth of cut, and filler material Graphene Oxide. The optimized conditions were found as cutting speed (Vc) 37.12 m/min, spindle feed (F) 80 mm/min, depth of cut (D) 0.5 mm and filler material Graphene Oxide (G) 1 wt.%. The percentage contribution of the process parameter on the delamination factor (Fd) was determined using the Analysis of Variance (ANOVA) method, and it has been found the feed rate (62.60%) is the most influencing factor. The delamination factor obtained in the confirmatory experiments carried out under optimized conditions was found lower than the Taguchi design test runs. The findings indicate that process parameter optimization under the given set of experimental conditions is effective for a manufacturing environment.

OPTIMIZATION USING RESPONSE SURFACE METHODOLOGY AND ARTIFICIAL NEURAL NETWORK IN GEARED DRILLING

Drill on different layered composite causes to force the layers ahead of it, creating unacceptable delamination on the leaving side. The current work describes the influence of different process parameters like spindle speed, feed, diameter of drill bit and addition of filler material on delamination damage on carbon and jute hybrid fiber composites during drilling operation. The experimental output for delamination is optimized by RSM-Response Surface Methodology and ANN-Artificial Neural Network Model. The experimental prediction model was established by considering DOE (design of experiments) of three levels performed with drilling operation by varying above said process parameters The optimum values for minimized delamination damage conditions found to be at (J-C-C-J) +5g of filler (fly-ash) composite. This is drilled with 8.5mm diameter drill bit with a feed of 0.08mm/rev at 875rpm speed. From the theoretical results it is recognized that cutting-speed and filler-material have much influencing factors on responses (delamination), and their individual contribution in an order of 47.25% and 47.32% respectively. By using Box-Behnken design RSM model is developed, with a feed-forward back-propagation method to develop the predictive ANN model which consists of 15 neurons in its hidden layer along with ANN Model. Here ANN Results (R2=0.99and RMSE=1.99) showed that the developed model is performing better to predict content of delamination when compare to RSM results (R2=0.97and RMSE=2.24).

Microstructure and Mechanical Properties of Welded Joints of 1.4462 Duplex Steel Made by the K-TIG Method

K-TIG (Keyhole Tungsten Inert Gas) method is a new, emerging welding technology that offers a significant acceleration of the joining process, even for very thick plates. However, its potential for welding of certain materials is still unknown. Particularly challenging are duplex steels as this technology does not allow the use of a filler material, which is crucial for these steels and for weld joint microstructure adjustment. In order to demonstrate the suitability of this technology for single-pass welding of 1.4462 duplex steel detailed studies of the microstructure of the weld joints obtained for different linear energies were carried out and discussed with respect to their mechanical properties. According to the results obtained, the heat-affected zone (HAZ) shows a microstructure similar to the HAZ of duplex steel welded with the traditional TIG multi-pass methods. However, the weld, due to the lack of filler material, had a microstructure different to that typical for duplex steel welded joints and was also characterized by an increased content of ferrite. However, all joints, both in terms of microstructure and mechanical properties, met the requirements of the relevant standards. Moreover, the K-TIG process can be carried out in the linear energy range typical of duplex steel welding, although further optimization is needed.

Non-Destructive X-ray Characterization of a Novel Joining Method Based on Laser-Melting Deposition for AISI 304 Stainless Steel

In this study, an application of the laser-melting deposition additive manufacturing technique as a welding method has been studied for the laser welding (LW) of AISI 304 stainless steel, specifically 0.4 mm and 0.5 mm thick sheets. The welding was carried out without and with filler material. Inconel 718 powder particles were used as filler material in the second case. A series of experiments were designed by changing the process parameters to identify the effect of operating conditions on the weld width, depth, and height. The welds were examined through metallographic experiments performed at various cross-sections to identify the defects and pores. All the deposited welds were passed through a customized mini-focus X-ray system to analyze the weld uniformities. The optimal operating conditions were determined for 0.4 mm and 0.5 mm sheets for the LW with and without filler material. It was found that laser power, laser scanning speed, powder flow rate, and helium to argon gases mixture-control the weld bead dimensions and quality. X-ray analyses showed that the optimal operating conditions gave the least peak value of non-uniformity in the laser welds. This study opens a new window for laser welding via additive manufacturing with X-ray monitoring.

Experimental investigation on cladding with metal cored wire using GMAW process and parametric optimization

Cladding is widely used in manufacturing industries for the production of pressure vessel by depositing thick layer of filler material for providing corrosion resistant-surface. The use of metal cored wire in gas metal arc welding (GMAW) process is popular due to its higher deposition rate and productivity. This work investigates the effect of process parameters on the deposition of cladding layer with ER 309L metal core wire (as filler material) on a corrosion resistant material (IS 2062). The welding parameters viz., wire feed rate (WFR), voltage (V), welding speed (S) and nozzle to plate distance (NTD) are employed as process parameters while penetration (P), bead width (W), reinforcement (R), weld penetration, shape factor (WPSF) and weld reinforcement form factor (WRFF) as welding responses. The predictive model developed for P, W, R, WPSF, and WRFF using the response surface methodology (RSM) approach is found adequate at 95% confidence interval. The validation results for the developed model results in a model accuracy (MA) of 92.82%, 96.34%, 91.47% 88.98% and 87.75% for model P, W, R, WPSF, and WRFF respectively and it shows higher predictability and accuracy. The process parameters are optimized simultaneously with integrated optimization approach using RSM with Jaya algorithm and obtain optimal solution in less than 20 number of iterations. The minimum fitness value obtained as 1.3008 at an optimal parameter setting of WFR=12m/min, V=26V, S=280mm/min, NTD=10mm. The validation result at the optimal parameter setting results in an improvement of 6.45%, 11.29%, 13.58%, 16.07%, 15.38% is noted for P, W, R, WPSF, and WRFF respectively.