Cutting Rate and Surface Characteristic Analysis in CNC Wire Electrical Discharge Machining of Aluminium Bronze

In this study, cutting rate and surface characteristic analysis in wire electrical discharge machining of aluminium bronze were investigated. Cutting rate analyses were performed according to Taguchi L18 (2^1×3^2) orthogonal array. Machining parameters such as wire type, duration between two pulses (BT) and pulse time (AT) were used as control factors. Raw data obtained for cutting rate were converted to S/N ratio values. Optimum levels of the machining parameters for cutting rate were determined using analysis of signal-to-noise (S/N) ratio. Significant machining parameters and their percentage contributions on results were obtained using Analysis of Variance (ANOVA). Regression analysis was performed to model the relationship between cutting rate and machining parameters. Analyses of surfaces machined of workpiece using both two wires for minimum and maximum cutting rate were observed using scanning electron microscope (SEM) and surface roughness device

Buckling Analyses of Axially Functionally Graded Nonuniform Columns with Elastic Restraint Using a Localized Differential Quadrature Method

A localized differential quadrature method (LDQM) is introduced for buckling analysis of axially functionally graded nonuniform columns with elastic restraints. Weighting coefficients of differential quadrature discretization are obtained making use of neighboring points in forward and backward type schemes for the reference grids near the beginning and end boundaries of the physical domain, respectively, and central type scheme for the reference grids inside the physical domain. Boundary conditions are directly implemented into weighting coefficient matrices, and there is no need to use fictitious points near the boundaries. Compatibility equations are not required because the governing differential equation is discretized only once for each reference grid using neighboring points and variation of flexural rigidity is taken to be continuous in the axial direction. A large case of columns having different variations of cross-sectional profile and modulus of elasticity in the axial direction are considered. The results for nondimensional critical buckling loads are compared to the analytical and numerical results available in the literature. Some new results are also given. Comparison of the results shows the potential of the LDQM for solving such generalized eigenvalue problems governed by fourth-order variable coefficient differential equations with high accuracy and less computational effort