Modeling and Simulation of Additively Manufactured Cylindrical Component Using Combined Thermomechanical and Inherent Strain Method with Nelder-Mead Optimization

This research concerns on the application of combined thermomechanical-inherent strain method (TMM-ISM) in predicting the distortion of additively manufactured component. The simulation and experimental verification were conducted in the form of vertical cylinder using selective laser melting, which was subsequently cut in the middle section. The setup and procedure of simulation approaches followed the actual process parameters such as laser power, layer thickness, scan strategy, and temperature dependent material, including flow curve retrieved from specialized computational numerical software. The investigation began with virtual calibration test using TMM, followed by manufacturing process simulation using ISM. Based on the maximum deformation result of simulated calibration and accuracy consideration from previous equivalent study, the inherent strain values used in ISM analysis were obtained using self-developed optimization algorithm with direct pattern search Nelder-Mead method in finding the minimum error of distortion using MATLAB. The error minima were measured between transient TMM-based simulation and simplified formulation in calculating the inherent strain values with respect to longitudinal and transverse laser directions. Furthermore, the combined TMM-ISM distortion results were compared to fully TMM with equivalent mesh number and verified based on experimental investigation conducted by renowned researcher. It can be concluded that the result of slit distortion from TMM-ISM and TMM showed good agreement with the error percentage of 9.5% and 3.5%, respectively. However, the computational time for combined TMM-ISM was reduced tremendously with only 63 min if compared to TMM with 129 min in running full simulation on solid cylindrical component. Hence, combined TMM-ISM-based simulation can be considered as an alternative method to replace time-consuming and cost-intensive calibration preparation and analysis.