Resumo:
The determination of the imposed heat rate in welding processes has always been an
obstacle to the modeling of this problem. Thus, the use of inverse problem techniques
is an alternative to estimate the unknown heat rate. This work presents a numerical experimental methodology for estimating the thermal input in welding processes. A mod ification of the iterative Function Specification Method is used to consider the thermal
sensitivity of the temperature moving sensor as a function of time and the position in
relation to the weld bead. In this way, it is possible to solve highly nonlinear problems
with a large gradient of temperature near the measurement sensors. Once the heat rate
was estimated, the thermal efficiency of the process as a function of the welding power
was determined. In this work, thermal efficiencies for TIG welding experiments on AISI
304 steel and laser welding on AISI 1020 steel were estimated. A detailed analysis of ther mal efficiency as a function of welding parameters was also carried out using the Taguchi
method for the TIG welding case. In the case of laser welding, a multiphysical model to
estimate thermal efficiency was proposed, in which the movement of the molten metal in
the weld pool is considered. A computer program using the feature Livelink for Matlab
was developed to solve the proposed inverse problem and it is explained in this work.
