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RISS 인기검색어
- 검색키워드
- 저자 : Murugaiyan Amirthalingam (검색결과 2 건)
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Nagaraj Pradeep,Prakash Sadasivam,Gurunathan Saravana Kumar,Murugaiyan Amirthalingam 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.4
Gas metal arc-based wire arc additive manufacturing (GMA-WAAM) is an attractive process for producing geometricallysimple and large-volume components. In this process, the arc energy and droplet transfer behaviour are primarily controlledby the current–voltage waveforms. Finite element analysis based on 3D transient gas metal arc heat source models has beenextensively used to derive mean process parameters and predict the thermal fields during GMA-WAAM. These models oftensimplify a complex current–voltage waveform by averaging it over a defined time period and use heat source efficiency,heat source parameters, and heat transfer co-efficient as fitting parameters. This simplification leads to inaccuracy in thepredictions of thermal fields. Therefore, a data-driven-based approach is proposed in this work to develop a physically-basedinstantaneous arc heat source model. This model is aimed to effectively describe a complex current–voltage waveform usedfor controlled dip short-circuiting transfer by adapting goldak’s double ellipsoidal arc heat source model. Instantaneousheat source parameters are derived from constant current waveform experiments corresponding to individual instances in ashort-circuiting current–voltage waveform. Arc energies are calculated as a function of instantaneous heat source parameterswhile depositing 1.2 mm diameter Al-Si12 (ER4047) wires on a pure aluminium substrate. Thermal fields are measured usingthese instantaneous parameters and validated with experimental observations. Results show that this data-driven approachpredicts the thermal fields with less than 1% relative error in the peak temperatures using the physically accurate heat sourceefficiency, heat source, and heat transfer parameters for a GMA-WAAM process.
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Jai Tiwari,Bashista Kumar Mahanta,Hariharan Krishnaswamy,Sivasrinivasu Devadula,Murugaiyan Amirthalingam 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.8
Application of electric current pulses while deforming a material, commonly referred to as electric-assisted forming (EAF), isknown to have desirable effects over its formability. In the finite element simulation of this electric-assisted deformation, thetime-temperature profile is obtained by providing various temperature dependent thermo-physical properties of the material. Out of all the required properties for such analysis, effective heat transfer coefficient and Joule heat fraction are sensitive tothe microstructure of the material, geometry of the specimen and the ambient conditions. Generally, these coefficients areidentified by iterative FE simulations. A clear methodology to estimate these parameters has not been established yet. In thepresent work, a procedure is developed using a genetically evolved meta-model of the time-temperature profile, which isexperimentally obtained from the pulsed current assisted uniaxial tension and compression tests. For this purpose, variousmulti-objective optimization techniques such as BioGP, EvoNN and cRVEA have been utilized to estimate the temperatureprofile in each case. It is shown that the tri-objective optimization procedure predicts the experimental temperature profilewith greater accuracy (within ± 5%) and is best suited to obtain the thermal modelling parameters of electric-assisted deformation,than other optimization techniques used in this work.
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