Towards numerical determination of distortion in laser welding

Kohl S, Hugger F, Mann V, Schmidt M (2014)


Publication Language: English

Publication Type: Conference contribution

Publication year: 2014

Publisher: BIAS

City/Town: Bremen

Pages Range: 173-184

Conference Proceedings Title: Thermal Forming and Welding Distortion: Proceedings of the IWOTE`14:International Workshop on Thermal Forming and Welding Distortion

Event location: Bremen DE

ISBN: 978-3-933762-48-1

Abstract

During the development of new products, the influence of production technologies on the properties of the components have to be taken into account. Examples for undesired effects on the assembly geometry are back-bending or welding distortions, which can significantly change the dimensions of a part during the production process. Especially in welding, the welding distortion is strongly dependent on the chosen parameters, as these have a significant influence on the shape of the weld seam and hence the distortion. However, the resulting deformation has to be known in the design phase before production starts. Consequently, cost-expensive and time-consuming experimental investigations are necessary for optimization of the process parameters. For reduction of the experimental effort, numerical simulations have the potential to predict the resulting properties of the assembly and therefore, they offer the opportunity of making the development of production processes more time and cost-efficient. Nevertheless, currently there is no model available that enables virtual development of a product with intrinsic process parameter optimization.
In this paper, we present experimental results of the influence of welding parameters upon welding distortion in fillet weld configuration. The investigated parameters are energy input per unit length, focus position, beam displacement and angle of incidence. We measured the distortion of the high strength steel welds time-resolved via several tactile sensors while we determined the weld seam shape by cross-section analysis and high-speed imaging. The investigated geometrical factors are compared to those of numerical process simulations. In the simulations we used a transient fluid dynamical finite volume model published previously. The model takes into account heat input by angle and polarization dependent absorption as well as multiple reflections inside the keyhole. Also, the model includes phase changes and their enthalpies, conductive and convective heat transfer and a keyhole surface calculated self-consistently from surface tension, flow pressure and evaporation pressure. We evaluate and compare the results of the simulation model regarding weld seam geometry and distortion to the experimental work in order to reach a numerical simulation model for welding distortion which will facilitate completely virtual product design without the need of prior experimental investigations.

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APA:

Kohl, S., Hugger, F., Mann, V., & Schmidt, M. (2014). Towards numerical determination of distortion in laser welding. In Prof. Frank Vollertsen, Hendrik Tetzel (Eds.), Thermal Forming and Welding Distortion: Proceedings of the IWOTE`14:International Workshop on Thermal Forming and Welding Distortion (pp. 173-184). Bremen, DE: Bremen: BIAS.

MLA:

Kohl, Stefanie, et al. "Towards numerical determination of distortion in laser welding." Proceedings of the International Workshop on Thermal Forming and Welding Distortion, Bremen Ed. Prof. Frank Vollertsen, Hendrik Tetzel, Bremen: BIAS, 2014. 173-184.

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