3-5 November 2021
Wirtschaftskammer Österreich
Europe/Vienna timezone

Prediction of residual stress development and subsequent springback deformation for the laser powder bed fusion process using multiple modelling strategies and a comprehensive validation framework

5 Nov 2021, 10:30
20m
SAAL 1

SAAL 1

Oral Presentation AM Process- and Quality Control MODELLING & SIMULATION

Speaker

David Ohlsson (RISE)

Description

To accurately describe the Selective Laser Melting with the goal to study residual stress development and deformations induced by the manufacturing process is very challenging due to the complex physics of the process. A concentrated, fast moving heat source on a very small scale in intricate patterns, multiphysics and metallurgy combined creates quite a challenge. In this work, methods from the field of Verification and Validation are applied to quantify the predictive capacity of the employed simulation tools.

In the project, a Design of Experiments approach was utilized whereby several input variables (specimen geometry and manufacturing process parameters) were varied. For each of the DoE points a physical specimen was manufactured which was then subjected to a cutting operation resulting in a geometrical distortion due to the residual stress state. The change in geometry was measured both using Digital Image Correlation (DIC) and laser scanning. The obtained data was then used to evaluate the predictive capacity of the employed simulation tools.

Macroscopic input variables like cantilever thickness and preheater temperature are evaluated with macroscopic simulation methods (low-resolution simulation) while microscopic input variables like scan geometry are evaluated with microscopic (high resolution) methods. The low-resolution simulation methods are Simufact mechanical (inherent strain) and thermomechanical solvers on a component scale. The high resolution simulations are FCC:s in-house LastFEM on up to 10 power layer scale. The high-resolution simulation has also been evaluated to provide inherent strain distribution input to low resolution mechanical simulation. Extensive material characteristics for maraging tool steel grade has been provided from Uddeholm.

The project illustrates how validation approaches can be used to support the process of developing and evaluating simulation tools and their ability to predict the characteristics of a component manufactured through additive manufacturing.

Primary authors

David Ohlsson (RISE) Dr Christos Oikonomou (Uddeholm AB) Dr Erik Dartfeldt (RISE) Dr Samuel Lorin (Frauenhofer Chalmers Centre) Mr Henrik Andersson (Uddeholm AB)

Presentation Materials