Process modelling and optimization of keyhole plasma arc welding of thin Ti-6Al-4V

Abstract

This article presents a comprehensive piece of research work focused on the development, validation and application of finite element modelling capability for the prediction and optimization of robotic keyhole plasma arc welding of Ti-6Al-4V thin structures. Experimental and computational investigations were carried out to characterize, develop, optimize and validate various aspects of the finite element modelling. The experimental investigations cover the determination of welding parameter envelopes using a robotic welding cell and the measurements of thermal history, distortion, residual stress and weld pool profile. The computational investigations include the development and validation of finite element models as well as the development and validation of a fully automated welding sequence optimization tool using a genetic algorithm approach. The work provides useful guidance and generic methodologies for optimum design of thin and complex lightweight structures and has formed a basis for the development of a framework on structural integrity assessment and component lifing of thin structures fabricated by welding. The optimization tool has significant potential to be conveniently modified to suit other optimization objectives and/or welding processes.

Residual stress distribution in a Ti–6Al–4V T-joint weld measured using synchrotron X-ray diffraction

“…In the T-joint with two partially overlapped passes, the residual stresses of the areas close to the first pass are more significant than those near the second pass. The results are in good agreement with the FE predicted results obtained in the NIMRC project work [21].…”

“…The measurement results were compared to the published numerical modelling results by Sun et al 22 The FE modelling was carried out using the full three-dimensional (3D) brick elements available in the welding-specific modelling software package SYSWELD, where the temperature-dependent thermal mechanical properties for Ti64 used are those which were available in the software. The FE model applied identical geometries as those of the sample in the synchrotron X-ray diffraction measurement, with temperature-dependent thermo-mechanical material properties used (e.g.…”

“…The results are in good agreement with the FE-predicted results obtained in the Nottingham Innovative Manufacturing Research Centre (NIMRC) project work. 22…”

“…The measurement results were compared to published numerical modelling results by the authors [21]. The finite element (FE) modelling was carried out using the full 3D brick elements available in the welding specific modelling software package SYSWELD, where the temperature dependent thermal mechanical properties for Ti64 used are those which were available in the software.…”

Numerical Simulation and Experimental Validation of MIG Welding of T-Joints of Thin Aluminum Plates for Top Class Vehicles

“…[1][2][3][4] The main drivers are product design, high-performance materials, and technological processes. [5][6][7][8] During last decade, [9] thanks to the improvement in the structural optimization techniques it is also possible to reduce sections of product design. In the modern automotive industry, thicknesses lower than 3 mm are widely employed for structural assemblies, as chassis or suspensions.…”