About this Abstract |
Meeting |
2020 AWS Professional Program
|
Symposium
|
2020 AWS Professional Program
|
Presentation Title |
An Efficient Part-scale Model to Predict Distortion on Overhang Structure in Laser Powder Bed Fusion Additive Manufacturing |
Author(s) |
Xuesong Gao, Tyler High, Wei Zhang , Hyeyun Song |
On-Site Speaker (Planned) |
Xuesong Gao |
Abstract Scope |
Overhang structures represent a common feature of complex geometries produced by additive manufacturing (AM). These structures are much more prone to distortion than the base section due to factors such as different thermal behaviors. The presence of distortion, if left uncontrolled, can cause the building process to abort prematurely or if the build is completed, subsequent dimensional inaccuracy and part fit-up issue. In this research, an efficient part-scale thermo-mechanical model was developed to study the transient thermal stress and distortion in an overhang structure printed by laser powder bed fusion (L-PBF) AM. In the model, the thermal and mechanical simulations were done sequentially with temperature field from the former being inputted as thermal load in the latter. The material deposition was realized by element birth method where the elements belonging to the oncoming deposited layers were deactivated at the beginning and orderly activated with the material deposition layer by layer. To reduce the computational expense, a layer-by-layer heat conduction analysis was carried out rather than the moving heat source calculation with individual melt tracks which was impractical on a part scale. Additionally, an adaptive meshing strategy was also utilized to reduce the computational efforts. To validate the model, overhang structures were built on a base plate with in-situ temperature and distortion measurement by infrared camera and profilometry, respectively. Based on the results, the evolution of thermal stress and distortion on the overhang structure was studied and the effect of several processing parameters on distortion were compared. |
Proceedings Inclusion? |
Definite: Other |