Multi-criteria calibration of a welding heat-transfer model: Balancing geometric and temperature-based objectives

Calibration of heat-source parameters and boundary heat losses is essential for reliable numerical welding simulations. This paper applies Grey relational analysis with entropy-based weighting to calibrate a three-dimensional heat-transfer model for gas metal arc welding of P355GH steel. Eight parameters are calibrated simultaneously: five describing the Goldak double-ellipsoidal heat source and three describing convective and radiative losses. Latin hypercube sampling with 80 combinations is used to explore the parameter space, and five objective functions are defined: three geometry-based and two temperature-based. Three calibration scenarios are compared: geometry-based, temperature-based, and combined, revealing a pronounced trade-off between geometric and thermal criteria. The combined scenario yields physically plausible parameter values and balanced prediction quality for both fusion-zone geometry and peak temperature indicators, and is therefore recommended for practical calibration of welding heat-transfer models.