Experimental-based methodology for the double ellipsoidal heat source parameters in welding simulations

Chujutalli, John H.; Lourenço, Marcelo Igor; Estefen, Segen F.

doi:10.1007/s40868-020-00074-4

Cited by 21 publications

(17 citation statements)

References 39 publications

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“…There are slight con icts are happened due to this modi cation of result analysis. This made the impact on nding the in uence of the parameter that controls the outputs [20]. So in-depth analysis is needed to nd out the signi cance of all the variable involved in the Goldack model.…”

Section: Resultsmentioning

confidence: 99%

The Role of Goldack Double Ellipsoidal Parameters in Temperature Distribution for the GTAW Process

Karpagaraj¹,

Suresh²,

Thamizhmanii³

et al. 2020

Preprint

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Numerical simulation is widely used in all the fields of engineering to predict the results. In welding, various finite element tools are used to predict the bead profile, temperature distribution, joint strength, formability and metallurgical changes etc. With respect to the welding process suitable heat source model has to be assigned for numerical simulation. The most suitable heat source for Gas Tungsten Arc Welding (GTAW) process is the Goldack double ellipsoidal model. This model has few parameters like the width of the weld (a), depth of penetration (b), front profile ellipse (Cf) and rear ellipse profile (Cr). In this research article, the influence of these parameters and their effect on the temperature distribution is focused. For this purpose, based on the full factorial design welding simulations are performed with COMSOL. Later, the grey relational technique was used to find the contribution of these parameters. It was concluded from the full factorial method that; temperature variation is depended on the GTAW welding heat source parameters. At 95% confidence level, the width of the weld showed a major role in controlling the temperature. Moreover, the optimum combination of process variables obtained end with minimum temperature rise at a width of 0.7 mm, depth of 5.7 mm and frontal factor of 4.

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Section: Resultsmentioning

confidence: 99%

The Role of Goldack Double Ellipsoidal Parameters in Temperature Distribution for the GTAW Process

Karpagaraj¹,

Suresh²,

Thamizhmanii³

et al. 2020

Preprint

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“…Ultimately, the geometrical parameters are unknown in the simulation of a weld using the double ellipsoid schematisation of the heat flux (a, b, c f and c r ). Often these parameters can be related to each other, as reported in [7,8], with c r = 4c f and c f = b. In this way, the only unknowns to determine are a and b.…”

Section: Description Of the Semi-analytical Methodsmentioning

confidence: 99%

A semi-analytical method for the calculation of double-ellipsoidal heat source parameters in welding simulation

Trupiano

Belardi

Fanelli

et al. 2022

IOP Conf. Ser.: Mater. Sci. Eng.

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Structural integrity assessment of welded components requires the determination of residual stress and deformations induced by the welding process. The implementation of both a numerical static mechanical analysis and a thermal transient analysis is needed in order to accurately determine stress and strain fields. The most faithful representation of the heat flow provided by the welding torch in thermal simulations is realized with Goldak’s double ellipsoid, especially in case of MIG/MAG and combined TIG-MIG/MAG welding. The correct determination of the temperature trends during the welding process simulation is essential for the subsequent mechanical FEA. In order to obtain the above-mentioned temperature trends, some parameters must be determined ex ante, e.g., the geometrical characteristics of Goldak’s double ellipsoid. Generally, a large number of trial simulations must be performed in order to define these parameters. However, manual fitting is often complicated. To overcome such difficulties, in this work, it is reported a combined analytical and numerical method to determine the parameters using the genetic algorithm NSGA-II. First-attempt parameters are obtained through the solution of the Fachinotti’s analytical formulation. This first stage requires a restricted set of experimental data, such as weld pool extension and one temperature trend in the proximity of the seam. Afterwards, first-attempt parameters and experimental data are used to determine the final parameters by means of a set of numerical thermal simulations guided through the genetic algorithm optimization. To confirm the good-functioning of the method, a numerical analysis for the simulation of the experimental data and another FE simulation performed with the final results of the method are presented.

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“…A mathematical model of moving heat source was proposed for 3D analysis [ 11 ]. The double ellipsoid distribution model developed by Goldak et al [ 12 ] is widely accepted for welding simulation, such as shielded metal arc welding (SMAW), flux-cored arc welding (FCAW), submerged arc welding (SAW), plasma arc welding (PAW), and gas metal arc welding (GMAW) [ 13 , 14 , 15 , 16 ]. Numerous application in building thermomechanical simulation for distortion evaluation for Ti-6Al-4V in directed energy deposition [ 17 ].…”

Section: Introductionmentioning

confidence: 99%

Heat Source Modeling and Residual Stress Analysis for Metal Directed Energy Deposition Additive Manufacturing

et al. 2022

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The advancement in additive manufacturing encourages the development of simplified tools for deep and swift research of the technology. Several approaches were developed to reduce the complexity of multi-track modeling for additive manufacturing. In the present work, a simple heat source model called concentrated heat source was evaluated for single- and multi-track deposition for directed energy deposition. The concentrated heat source model was compared with the widely accepted Goldak heat source model. The concentrated heat source does not require melt pool dimension measurement for thermal model simulation. Thus, it reduces the considerable time for preprocessing. The shape of the melt pool and temperature contour around the heat source was analyzed for single-track deposition. A good agreement was noticed for the concentrated heat source model melt pool, with an experimentally determined melt pool, using an optical microscope. Two heat source models were applied to multi-track 3D solid structure thermo-mechanical simulation. The results of the two models, for thermal history and residual stress, were compared with experimentally determined data. A good agreement was found for both models. The concentrated heat source model reported less than the half the computational time required for the Goldak model. The validated model, for 3D solid structure thermo-mechanical simulation, was used to analyze thermal stress evolution during the deposition process. The material deposition on the base plate at room temperature results in lower peak temperatures in the layers near the base plate. Consequently, the higher thermal stress in the layers near the base plate was found, compared to the upper layers during the deposition process.

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Experimental-based methodology for the double ellipsoidal heat source parameters in welding simulations

Cited by 21 publications

References 39 publications

The Role of Goldack Double Ellipsoidal Parameters in Temperature Distribution for the GTAW Process

The Role of Goldack Double Ellipsoidal Parameters in Temperature Distribution for the GTAW Process

A semi-analytical method for the calculation of double-ellipsoidal heat source parameters in welding simulation

Heat Source Modeling and Residual Stress Analysis for Metal Directed Energy Deposition Additive Manufacturing

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