Applied Mechanics and Materials Vol. 895

Abstract: The main objective of this paper is to present prototype of wing spar joint using CATIA V5 software to study the behavior of wing spar joint as per actual working condition and to perform structural analysis of the wing spar joint based on condition of cyclic loading (fatigue loading). Determining the loading modes in the spar joint is subjected to static load and fatigue loads which should be taken into account in the evaluation of the strength and fatigue life. Initially, the components were modeled with CATIA V5 and imported to MSC PATRAN; MSC NASTRAN is used as a solver. From the obtained maximum tensile stresses, fatigue analysis was carried out to find fatigue life of the spar joint with different fatigue load spectra.

Abstract: Processing of metallic materials using microwave energy offer benefits of time compression and energy saving during applications such as sintering, casting, melting, joining and cladding. However, use of microwave energy is uncommon for machining of metallic materials because of high reflectivity. The present work aims to study microwave-metal (MW-m) discharge-induced plasma channel (PC) characteristics during microwave drilling of thin stainless steel (SS) sheet (0.6 mm) at 2.45 GHz. Experimental trials inside two different microwave applicators A1 and A2 were monitored and recorded. The images of the plasma channel generated in both the microwave applicators were obtained at different time intervals to analyze the plasma channel diameter (PCD). Experimental results revealed that variation in the microwave power significantly affects the dimension of plasma channel generated in the tool-work gap and heat affected zone (HAZ) formed around the drilling zone. Reduction in microwave drilling time of approximately 80% was observed at 3 kW power compared to drilling time at 0.7 kW power. The HAZ observed in the samples drilled at 0.7 kW was significantly higher than the HAZ observed at 3 kW owing to higher drilling time of samples at 0.7 kW.

Abstract: In the present work a detailed microstructural investigation of Cobalt based microwave cladding on S-355 stainless steel was carried out. The experimentations were carried out in a home based domestic microwave oven. This article clears the circumstances of clad formation during microwave hybrid heating. The solidification texture and grain structure of the developed clad scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscopy, and measurement of Vicker’s microhardness. Cobalt based clads developed with an approximate thickness of 1 mm without interfacial cracking. The microstructure of clad clearly illustrated excellent metallurgical bond with S-355 substrate and found dominantly fine cellular grains. Iron and cobalt were recognized inside the cells while chromium was ascertained segregated around the cell boundaries. The average microhardness of the cobalt based clad was observed in the range of 402±60 HV.

Abstract: This study has been carried out to demonstrate the effect of short carbon fiber (SCF) loading on static and dynamic mechanical performance of polyethersulfone (PES) composites. Different combinations of SCF/PES composites were prepared by extrusion followed by injection molding. The static mechanical properties such as hardness, tensile and flexural properties of PES based composites were analyzed following ISO standards. As engineering materials, the polymer composites with high modulus as well as excellent damping properties are of great interest in aerospace and automotive industries for severe dynamic environment. Furthermore, in addition to static properties of composites, dynamic mechanical behaviour of PES based composites was evaluated. Mechanical test results showed that increasing the SCF wt. % in the composites increases the hardness, tensile and flexural properties. Furthermore, the optimal SCF loading was found to be 30 wt. % for significantly improving the overall composite mechanical performance. Upon the reinforcing of SCFs, an improvement in the storage modulus was found. Based on the fractographic analysis, orientation and aligned structure of carbon fibers, good bonding of fibers within the matrix and better fiber-matrix interaction were the primary reasons leading to the improvement of mechanical properties. The optimized composite (PES with 30 wt. % of SCF) could be used in automotive components like frames, flap covers and gears of printing machinery.

Abstract: Hybrid composites based on high-density polyethylene-grafted maleic anhydride /ultra-high density HYPERLINK "https://www.sciencedirect.com/topics/materials-science/polypropylene" \o "Learn more about Polypropylene" polyethylene (HDPE/UHMWPE) loaded with short glass fiber (SGF) and zirconia (ZrO₂) micron sized particles were fabricated by melt-mixing process and their physical and mechanical properties were determined. Physio-mechanical properties such as density, hardness, flexural properties and impact strength of these composites were studied. The presence of SGF and ZrO₂ in the grafted HDPE/UHMWPE blend increased the hardness, bending strength and modulus. However, impact strength decreased with increase in ZrO₂ loading. Further, it was found that the HDPE/UHMWPE blend with 25 wt. % SGF and 2.5 wt. %ZrO₂ showed optimum mechanical properties due to improved fiber/matrix adhesion. Scanning electron microscope was used to identify the fractographic features of the selected fractured coupons.

Abstract: Wear is one of the foremost issues faced in manufacturing industries that reduces the lifestyles of machine elements and will increase the running costs. Therefore, hardfacing is extensively employed by industry professionals to minimise the wear of moving components. In this research work, a nickel based alloy recognized as Hastelloy C-276 was strengthened on stainless steel (316L) substrate via the usage of Gas Metal Arc Welding (GMAW) technique. The coating thickness used to be assorted was from 1 to 3 mm on the substrate. The optical microstructure of the interface revealed the defect-free fusion between hardface and substrate metals. Microhardness (Hv) and three-body abrasive put on test have proven that the hardfaced alloy metal posses higher hardness and effective wear resistance. The worn surface morphologies have been found using SEM in order to perceive the involved wear mechanisms.

Abstract: Hydraulic actuators play a major role in aircraft flight actuation and control. Primary control systems in an aircraft typically control the components that guide an airplane during flight. Electro Hydrostatic Actuators (EHA) is emerging as a viable option for aerospace as well as industrial machine builders. It is an emerging technology which replaces centralized hydraulic system by a self-contained and localized direct drive actuator system. As most of the aircraft applications use symmetric actuator, Symmetric actuator EHA system configuration is considered in most of the literatures. However in case of many industrial applications, asymmetric actuators are being used. The dynamic response that means how fast an actuator reaches a target position is an important criteria for any application. An indigenous experimental setup of EHA system is developed with measuring instruments and sensors that forms a mechatronic system. The Variable Motor and Fixed Pump configuration of EHA is used for experimentation. In this work the load analysis is carried out on asymmetric and symmetric actuators. Similarly the load analysis is carried out on different controllers like Proportional Derivative (PD), Proportional Integral (PI) and Proportional Integral Derivative (PID) over the dynamic response as a output. It is found that symmetric actuator and PD controller gives better results.

Abstract: Simulation plays a vital role in present-day product development. Simulation of manufacturing process in product design and development helps to save valuable resources in terms of materials, energy and also in the optimisation of process parameters. Metal rolling accounts to majority of the materials used in the bulk-forming. It is difficult to predict metal flow in the lateral direction in the conventional metal rolling. Manufacturing the rollers of different shapes and conducting experiments physically consumes valuable resources. These valuable resource are saved using the simulation of rolling operations using FEM-based metal forming simulation software. Simulation experiments are carried out to determine the effect of different shapes of rollers on the spread of material. In this work, spread of the material is analysed when the material is passed through different shaped rollers. Three types of rollers have been designed to study the effect of adding grooves on the spread of materials. It is seen that smaller groove size decreases the spread whereas larger size groove on the rollers increases the spread.

Abstract: The friction stir welding is a solid state welding in which welding takes place at a temperature below the melting point. This welding is also known as green technology welding as no harmful gases are generated, as well as fluxes are not formed. In this process joining of two dissimilar materials can be achieved. Through this welding one can overcome defects like porosity, solidification, cracks etc by selecting suitable wilding parameters. Present work investigates the effect of different tool pin geometries on mechanical properties of friction stir welded AA6061 and AA7075 alloys keeping the process parameters constant. The welding is carried with process parameters 1000rpm, 50mm/min and 5KN as tool rotational speed, welding speed and axial load respectively, and for four different pin geometries: (a) cylindrical pin, (B) triangular pin, (c) square pin and (d) hexagonal pin. The welded samples are characterized by mechanical properties like tensile strength and micro Vickers hardness test. By considering the both properties the hexagonal pin shown better characteristics under optimum process parameters.

Abstract: This study evaluates the effect of process parameters on depth of penetration and surface roughness in abrasive waterjet (AWJ) cutting of copper. Full factorial experiments are carried out on trapezoidal blocks for each of the three abrasive particle sizes used. Experimental parameters - abrasive mass flow rate, water jet pressure and traverse speed are varied at three levels. Main effects and contributions of process parameters to depth of penetration and surface roughness is calculated. From the data, it is observed that, high abrasive mass flow rate, high water jet pressure and low traverse speed resulted in higher depth of penetration and a high abrasive mass flow rate, high water jet pressure and low traverse speed resulted in lesser R_a value. Using experimental data a statistical model for predicting depth of penetration & surface roughness is developed. Error between experimental and statistical values are compared to validate the statistical model. The maximum DOP of 49.32mm was observed at AMFR=405.4 g/min, P=300 MPa, TS=60 mm/min, MS=60 Mesh and minimum DOP of 4.27mm was observed at AMFR=200 g/min, P=100 MPa, TS=90 mm/min, MS=80 Mesh.