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- 摘要
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Optimization of welding parameters in laser welding of Ti6Al4V using VIKOR optimization method
摘要： Ti6Al4V alloys are widely preferred in the biomedical industries owing to its higher corrosion resistance in human body environment. Welding plays a critical role in the manufacture of complicated biomedical components. Hence, the necessity to identify suitable joining process for joining Ti6Al4V is very important. In this work, an attempt is made to study the CO2 laser welding of titanium sheets (Ti6Al4V) having dimensions of 100 (cid:1) 60 (cid:1) 3 mm. Laser welding was done based on L9 Taguchi array with welding speed (v), laser power(P), and shielding gas ?ow rate(f) as input parameters. The weld quality was analysed by measuring the depth of penetration (DOP), bead width (BW), and hardness values. Full penetration was observed only in two welding trials. The optimized parameters were identi?ed by using the VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) multi-objective optimization technique. Analytic Hierarchy Process (AHP) is used for determining the weights of the relative importance of the output factors. VIKOR method identi?ed that the 7th experimental run (power = 1.3 kW, speed = 0.3 m/min, shielding gas ?ow rate = 20 L/min) as the optimized parameter for getting the weld with full depth of penetration, lesser bead width, higher microhardness values in the fusion zone (FZ) and heat affected zone (HAZ). The metallurgical characterization of the optimized weld is also dicussed with the aid of microstructures taken from Scanning Electron Microscope (SEM).
关键词： CO2 laser welding,Hardness values,Bead geometry,VIKOR multi-objective optimization technique,Ti6Al4V
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE International Conference on Space Optical Systems and Applications (ICSOS) - Portland, OR, USA (2019.10.14-2019.10.16)] 2019 IEEE International Conference on Space Optical Systems and Applications (ICSOS) - Single-Mode Fiber Coupling with Adaptive Optics for Free-Space Optical Communication under Strong Scintillation
摘要： A joint optimization problem of link-layer energy efficiency (EE) and effective capacity (EC) in a Nakagami-m fading channel under a delay-outage probability constraint and an average transmit power constraint is considered and investigated in this paper. First, a normalized multi-objective optimization problem (MOP) is formulated and transformed into a single-objective optimization problem (SOP), by applying the weighted sum method. The formulated SOP is then proved to be continuously differentiable and strictly quasiconvex in the optimum average input power, which turns out to be a cup shape curve. Furthermore, the weighted quasiconvex tradeoff problem is solved by first using Charnes–Cooper transformation and then applying Karush–Kuhn–Tucker (KKT) conditions. The proposed optimal power allocation, which includes the optimal strategy for the link-layer EE-maximization problem and the EC-maximization problem as extreme cases, is proved to be sufficient for the Pareto optimal set of the original EE–EC MOP. Moreover, we prove that the optimum average power level monotonically decreases with the importance weight, but strictly increases with the normalization factor, the circuit power and the power amplifier efficiency. Simulation results confirm the analytical derivations and further show the effects of fading severeness and transmission power limit on the tradeoff performance.
关键词： energy efficiency,delay-outage probability constraint,multi-objective optimization problem,effective capacity,Quality-of-service,weighted sum method
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE Sustainable Power and Energy Conference (iSPEC) - Beijing, China (2019.11.21-2019.11.23)] 2019 IEEE Sustainable Power and Energy Conference (iSPEC) - Accessing Capacity Planning of Distributed Generations Considering the Temporal Correlation Characteristics of Wind-Photovoltaic-Load
摘要： Interference is one of the major obstacles to improving the performance in wireless communication systems. As the ever-growing data traffic is carried over extremely dense networks, how to deal with interference becomes even more relevant. In this paper, we investigate a network with N pairs of users transmitting on the same channel simultaneously from the energy efficiency (EE) perspective. For such an interference network, we aim to address two issues: what is the EE tradeoff between users and how to design energy-efficient resource allocation scheme? To answer these two questions, we formulate a non-concave multi-objective optimization problem (MOOP) to investigate the EE tradeoff, taking into account the minimum data rate requirement of each user. The weighted Tchebycheff method is utilized to solve the MOOP by converting it into a single-objective optimization problem, which is then solved by the Dinkelbach method and the concave-convex procedure method. Based on the above, a power control algorithm is developed for the interference network to achieve at least a local optimum. The proposed algorithm is compared with the orthogonal bandwidth sharing, where each user orthogonally shares the whole bandwidth without interfering each other. In this scenario, the weighted Tchebycheff and the Dinkelbach methods are also utilized to develop the optimal bandwidth allocation and power control algorithm. The performance of the proposed algorithms is verified by numerical results, which show that it is better to share the bandwidth orthogonally rather than non-orthogonally if the interference between each user pair is stronger than a given threshold.
关键词： multi-objective optimization,energy efficiency,Interference channel,bandwidth allocation and power control
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 21st Electronics Packaging Technology Conference (EPTC) - Singapore, Singapore (2019.12.4-2019.12.6)] 2019 IEEE 21st Electronics Packaging Technology Conference (EPTC) - A new substrate for realizing hemispherical encapsulant layer to enhance light efficiency of light-emitting diodes
摘要： A joint optimization problem of link-layer energy efficiency (EE) and effective capacity (EC) in a Nakagami-m fading channel under a delay-outage probability constraint and an average transmit power constraint is considered and investigated in this paper. First, a normalized multi-objective optimization problem (MOP) is formulated and transformed into a single-objective optimization problem (SOP), by applying the weighted sum method. The formulated SOP is then proved to be continuously differentiable and strictly quasiconvex in the optimum average input power, which turns out to be a cup shape curve. Furthermore, the weighted quasiconvex tradeoff problem is solved by first using Charnes–Cooper transformation and then applying Karush–Kuhn–Tucker (KKT) conditions. The proposed optimal power allocation, which includes the optimal strategy for the link-layer EE-maximization problem and the EC-maximization problem as extreme cases, is proved to be sufficient for the Pareto optimal set of the original EE–EC MOP. Moreover, we prove that the optimum average power level monotonically decreases with the importance weight, but strictly increases with the normalization factor, the circuit power and the power amplifier efficiency. Simulation results confirm the analytical derivations and further show the effects of fading severeness and transmission power limit on the tradeoff performance.
关键词： energy efficiency,weighted sum method,delay-outage probability constraint,Quality-of-service,effective capacity,multi-objective optimization problem
更新于2025-09-19 17:13:59
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Collaborative Optimization of Density and Surface Roughness of 316L Stainless Steel in Selective Laser Melting
摘要： Although the concept of additive manufacturing has been proposed for several decades, momentum in the area of selective laser melting (SLM) is ?nally starting to build. In SLM, density and surface roughness, as the important quality indexes of SLMed parts, are dependent on the processing parameters. However, there are few studies on their collaborative optimization during SLM to obtain high relative density and low surface roughness simultaneously in the literature. In this work, the response surface method was adopted to study the in?uences of di?erent processing parameters (laser power, scanning speed and hatch space) on density and surface roughness of 316L stainless steel parts fabricated by SLM. A statistical relationship model between processing parameters and manufacturing quality is established. A multi-objective collaborative optimization strategy considering both density and surface roughness is proposed. The experimental results show that the main e?ects of processing parameters on the density and surface roughness are similar. We observed that the laser power and scanning speed signi?cantly a?ected the above objective quality, but the in?uence of the hatch spacing was comparatively low. Based on the above optimization, 316L stainless steel parts with excellent surface roughness and relative density can be obtained by SLM with optimized processing parameters.
关键词： 316L stainless steel,multi-objective optimization,relative density,selective laser melting,surface roughness
更新于2025-09-19 17:13:59
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Prediction and Optimization of Deformations in Coupling Mechanism Based Laser Forming of Sheet Metals
摘要： Fabricating three dimensional shaped surfaces from flat sheet metals by laser forming, both out-of-plane and in-plane deformations are required. This article presents the modeling of coupling mechanism activated laser forming of sheet metals based on experimental data for prediction and optimization of bending and thickening deformations. Experiments were performed based on a central composite design of experiments on coupling mechanism based laser metal forming process considering the input process parameters like laser power, scan speed and spot diameter, bending and thickening were taken as the outputs. Neural network and neuro-fuzzy system-based models were developed to carry out both forward and inverse modeling of the laser metal forming process under the coupling mechanism. Multi-objective optimization based on the non-dominated sorting genetic algorithm was used to obtain multiple optimal solutions to achieve different amounts of out-of-plane and in-plane deformations. The proposed method could guide for a suitable selection of the process parameters to produce three-dimensional shapes utilizing coupling mechanism-based laser forming using multiple laser line heating.
关键词： Coupling mechanism,Soft Computing,Laser forming,Multi-objective optimization
更新于2025-09-16 10:30:52
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Optimization for Hydro-Photovoltaic-Wind Power Generation System Based on Modified Version of Multi-Objective Whale Optimization Algorithm
摘要： The intractable problem of the solar energy and wind energy are their discontinuity and instability cause by the environmental change. Hydropower was often chosen as the compensation of electric energy system for its celerity and low cost of adjustment and respond. This paper presents a long term multi-objective optimization model of hydro-photovoltaic(PV)-wind power system, in which, cascade hydropower station acts as the compensation of the power system. One objective of the model is maximizing the annual total power generation of the power system, and another objective is to smoothen the fluctuation of the power output of the system. This model calculates all the PV power and wind power at first, and then inputs the calculated results to the power grid as the boundary condition of the hydropower optimization. A modified version of non-dominated sorting whale optimization algorithm (modified NSWOA) is proposed to get a solution set of the proposed model. The results demonstrate that the modified NSWOA can provide decision maker a series of solutions for optimal selection and the hydropower can well compensate the PV power and wind power by its great adjusting ability.
关键词： Hydro-photovoltaic-wind power system,Multi-objective optimization,Cascade hydropower station,Modified non-dominated sorting whale optimization algorithm
更新于2025-09-12 10:27:22
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Coordinated optimal dispatch of photovoltaic units with updated power electronic transformer
摘要： The stochastic variation of photovoltaic (PV) generation units in the distribution grid has increased complexity of the optimal dispatch. Updated power electronics devices such as power electronics transformer (PET) are installed to improve the energy efficiency of DC power appliances and the control flexibility. The synergy effects of optimal dispatch of photovoltaic units and updated PET operation are analyzed in this paper. A two-stage optimization model is established to search for the best configuration and operation of distribution grid with updated PET feeders and photovoltaic inverters. The optimal configuration of PETs is given in the upper stage and given to the lower stage as input parameters to regulate the active and reactive power of photovoltaic inverters associated with operation of feeders updated with PETs. The coordinated optimization between updated PETs and photovoltaic generation units is developed to minimize the operation cost and total power losses in the distribution grid. NSGA-II algorithm is adopted to solve the proposed multi-objective optimization with constraints from both reliable operation of power system and power electronics devices. Comparisons between the simulation results with and without the proposed coordinated optimization for PETs and PVs valid the effectiveness of two-stage optimization model. The operation cost and power losses are reduced while avoiding the power curtailment of PV units by optimally configuring and regulating the power electronic devices including the PETs and inverters of PVs in the test distribution network.
关键词： multi-objective optimization,integration of photovoltaic generation,power electronic transformer,coordinated optimal dispatch
更新于2025-09-12 10:27:22
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Multi-Objective Optimization of Residual Stress and Cost in Laser Shock Peening Process Using Finite Element Analysis and PSO Algorithm
摘要： Laser shock peening (LSP) is an effective process utilized for surface enhancement of metal parts so that generating compressive residual stresses (RS) on the surface improves fatigue life of the material. The main affecting parameters on surface negative residual stress are laser power, laser beam size and shape, peening pitch and pattern. Varying these parameters alters the magnitude and depth of RS as well as the cost of LSP. An integrated method for simulation of optimum LSP process is presented in this paper, in which Particle Swarm Optimization (PSO) technique was employed utilizing Python coding in ABAQUS finite element environment to maximize the uniformity of compressive RS and minimize LSP cost on an Inconel 718 super-alloy specimen. The mentioned affecting parameters were selected as optimization parameters, and minimum acceptable amounts and depth of compressive RSs were two main design constraints. Simulation results were compared with previously published experimental ones, and optimum LSP variables were finally determined and presented for certain amount of design constraints. It was revealed that, relatively small circular laser beam, shot by square scanning pattern, leads to generate the most uniform RS with minimum LSP cost.
关键词： Particle swarm multi-objective optimization,Laser shock peening,Residual stress,Python coding,Finite element simulation
更新于2025-09-12 10:27:22
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Optimization of Pulsed Nd:YVO4 Through Transmission Laser Welding of Transparent Acrylic and Polycarbonate
摘要： In the present work through transmission laser welding (TTLW) of two transparent plastic materials namely, Acrylic and Polycarbonate at varied levels of laser power, scanning speed and frequency have been carried out to form lap joints without application of filler material. The effect of input parameters on the weld quality has been studied through inspection and tests. Statistical software Design Expert 10 has been applied for design of experiments and analysis purpose. Breaking load and weld width have been considered as responses. Response surface methodology (RSM) has been applied for multi-objective optimization for minimization of weld width and maximization of breaking load simultaneously. Confirmatory tests have been conducted to validate the applied optimization techniques.
关键词： Design Expert 10,Multi-objective optimization,RSM,TTLW,Acrylic and Polycarbonate
更新于2025-09-11 14:15:04