Microstructural and mechanical behavior of Al 6061/SiC-Al2O3 composites processed through friction stir processing

Metal Matrix Composite (MMC) reinforced in friction stir processing (FSP) has increased insights that can affectively attain the desired mechanical properties for the manufactured samples. The favorable conditions of carbides are considered for reinforcing the SiC particles into the Aluminum 6061. The methodology of fabricating Aluminum 6061 comprises of three materials, Al 6061-SiC-Al2O3. The experimental evaluation of the composite Aluminum 6061-SiC-Al2O3 includes the influence of process parameters on microhardness, tensile strength, and microstructure. As a result of the reinforcement of nanoparticles processed in FSP, the properties of composite material increased satisfactorily. The sample S3 observed to be having a maximum tensile strength of 185 MPa. The larger, the better condition is adopted to analyze the tensile strength of the fabricated samples. The optimum condition for maximum tensile strength was found at 900 RPM, 15 mm/min, and composition 3. The hardness profiles at different zones of friction stir processing (FSP), viz., Heat Affected Zone (HAZ), Thermo Mechanical Affected Zone (TMAZ), Nugget Zone (NZ) were examined. The characterization techniques deployed were optical microscope (OM), and scanning electron microscope (SEM) studies for microstructural behavior. The result shows that the reinforcements were tightly embedded into the base material surface. The spherical grains are formed in the reinforcement region

Large amplitude free vibrations of simply supported moderately thick rectangular plates using coupled displacement field method

In this paper a novel method known as Coupled Displacement Field Method was proposed to evaluate the large amplitude free vibration behavior of the moderately thick rectangular plates with simply supported boundary conditions. Here a single term trigonometric admissible displacement field was assumed for one of the variables, say the total rotations (in both X, Y directions). With the help of the coupling equations, the spatial variation for the lateral displacement field is derived in terms of the total rotations, where the two independent variables problem becomes one. The coupled displacement field method makes use of the energy formulation which contains half the number of unknown independent coefficients, in the case of a rectangular plate, when compared to the conventional Rayleigh-Ritz method. Closed form expressions for the linear and nonlinear fundamental frequency parameters for the all edges simply supported moderately thick rectangular plates are derived. The numerical results obtained from the present formulation are validated with those obtained from the existing literature for the given moderately thick plates

Fundamental frequency for large amplitude vibrations of uniform Timoshenko beams with central point concentrated mass using coupled displacement field method

Complex structures used in many fields of engineering are made up of simple structural elements like beams, plates, etc. These structural elements, sometimes carry concentrated point masses at discrete points, and when subjected to severe dynamic environment tend to vibrate with large amplitudes. Both the continuum and the finite-element solutions are available in the open literature to tackle this coupled nonlinear problem, without concentrated point masses with particular emphasis on the fundamental linear and nonlinear frequencies. However, for short beams and moderately thick plates, one has to consider the effects of shear deformation and rotary inertia to evaluate their fundamental linear and nonlinear frequencies. A commonly used method for obtaining the same is the energy method, or a finite-element analogue of the same. In this paper the authors used a coupled displacement field method where in the number of undetermined coefficients '2n' existing in the classical energy method are reduced to 'n', which significantly simplifies the procedure to obtain the analytical solution. The large amplitude free vibration behaviour of the most commonly used uniform shear flexible hinged-hinged and clamped-clamped beams with central point concentrated masses is studied here. This study reveals some interesting aspects concerned with the problem considered. The numerical results in terms of the linear frequency parameter and the ratios of nonlinear to linear radian frequencies for the uniform with a central point concentrated mass are given in the digital form