An Intelligent Predictive Model-Based Multi-Response Optimization of EDM Process

Electrical Discharge Machining(EDM)is a popular non-traditional machining process that is widely used due to its ability to machine hard and brittle materials.It does not require a cutting tool and can machine complex geometries easily.However,it suffers from drawbacks like a poor rate of machining and excessive tool wear.In this research,an attempt is made to address these issues by using an intelligent predictive model coupled global optimization approach to predict suitable combinations of input parameters(current,pulse on-time and pulse off-time)that would effectively increase the material removal rate and minimize the tool wear.The predictive models,which are based on the symbolic regression approach exploit the machine intelligence of Genetic Programming(GP).As compared to traditional polynomial response surface(PRS)predictive models,the GP predictive models show compactness as well as better prediction capability.The developed GP predictive models are deployed in conjunction with NSGA-II to predict Pareto optimal solutions.

A hydrochemical approach to estimate mountain front recharge in an aquifer system in Tamilnadu, India

Mountain-front recharge(MFR) is a process of recharging an aquifer by infiltration of surface flow from streams and adjacent basins in a mountain block and along a mountain front(MF). This is the first attempt in India to estimate MFR along the foothills of Courtallam using hydrogeochemistry and geostatistical tools. The estimation of MFR has been carried out by collecting groundwater samples along the foothills of Courtallam. Collected water samples were analyzed for major cations and anions using standard procedures. Hydrogeochemical facies show the existence of four water types in this region. Calcium-rich water derived from gneissic rock terrain indicates significant recharge from higher elevation. Log p CO_2 and ionic strength of the samples were also calculated to identify the geochemical process. Majority of the collected samples have sodium-rich water and weak ionic strength, which indicate foothill recharge and low residence time. Silicate and carbonate weathering have an equal interplay along the foothills with a relatively large fraction of Mg from the MF. The spatial diagrams of three factors show that the southern part of the study area is dominated by both weathering and anthropogenic processes, whereas the northern part is dominated by both leaching and weathering processes. Thus, the dominant weathering process represented by the second factor indicates the large recharge process along the foothills.

Multi-Objective High-Fidelity Optimization Using NSGA-III and MO-RPSOLC

Optimizing the performance of composite structures is a real-world application with significant benefits.In this paper,a high-fidelity finite element method(FEM)is combined with the iterative improvement capability of metaheuristic optimization algorithms to obtain optimized composite plates.The FEM module comprises of ninenode isoparametric plate bending element in conjunction with the first-order shear deformation theory(FSDT).A recently proposed memetic version of particle swarm optimization called RPSOLC is modified in the current research to carry out multi-objective Pareto optimization.The performance of the MO-RPSOLC is found to be comparable with the NSGA-III.This work successfully highlights the use of FEM-MO-RPSOLC in obtaining highfidelity Pareto solutions considering simultaneous maximization of the fundamental frequency and frequency separation in laminated composites by optimizing the stacking sequence.

Effect of surface blowing on aerodynamic characteristics of tubercled straight wing

Recent research proves that wings with leading-edge tubercles have the ability to perform efficiently in post-stall region over the conventional straight wing. Moreover, the conventional straight wing outperforms the tubercled wing at a pre-stall region which is quintessential. Even though tubercled wing offers great performance enhancement, because of the complexity of the flow, the trough region of the tubercled wing is more prone to flow separation. Henceforth, the present paper aims at surface blowing – an active flow control technique over the tubercled wing to enhance the aerodynamic efficiency by positively influencing its lift characteristics without causing any additional drag penalty. Flow parameters like blowing velocity ratios and the location of blowing were chosen to find the optimised configuration keeping the amplitude and frequency of the leading-edge tubercles constant as 0.12 c and 0.25 c respectively. Numerical investigations were carried out over the baseline tubercled wing and tubercled wing with surface blowing at various blowing jet velocity ratios 0.5, 1 and 2 over four different chordwise locations ranging from 0.3 c to 0.8 c.The results confirm that blowing at various x/c with different blowing velocity ratios performs better than the conventional tubercled wing. Comparatively, blowing velocity ratio 2 at 0.3 c shows peak performance of about 28% enhancement in the lift characteristics relative to the baseline model. Particularly, in the pre-stall region, 25–50% increase in aerodynamic efficiency is evident over the tubercled wing with surface blowing compared with the baseline case. Additionally,attempts were made to delineate the physical significance of the flow separation mechanism due to blowing by visualizing the streamline pattern.

A h-Adaptive Algorithm Using Residual Error Estimates for Fluid Flows

Algorithms for adaptive mesh refinement using a residual error estimator are proposed for fluid flow problems in a finite volume framework.The residual error estimator,referred to as theℜ-parameter is used to derive refinement and coarsening criteria for the adaptive algorithms.An adaptive strategy based on theℜ-parameter is proposed for continuous flows,while a hybrid adaptive algorithm employing a combination of error indicators and theℜ-parameter is developed for discontinuous flows.Numerical experiments for inviscid and viscous flows on different grid topologies demonstrate the effectiveness of the proposed algorithms on arbitrary polygonal grids.