Modeling of mechanical behavior in additive manufacturing at part scale

Qiang Chen,Erwan Beauchesne,Constantin Meis,Pierre-Richard Dahoo,Francis Arnaudeau

doi:10.1088/1742-6596/1391/1/012010

Abstract

Laser Beam Melting is actually capable of producing parts with reliable mechanical properties. However, efficient production still remains a challenge and high quality numerical simulation is required in order to understand the physical mechanisms involved. Consequently, a macroscopic numerical model at part scale is actually under development for understanding the relationship between different process and material parameters with the mechanical state of final parts such as distortion and residual stress. Classical finite element method is used to solve the coupled thermo-mechanical problem on the whole domain defined by the workpiece, the baseplate and the support structures. At this scale, powder packing is neglected as well as the hydrodynamics behavior within the melt pool. Homogeneous equivalent heat source is used and imposed until several layers below the current deposited layer. Elastoplastic constitutive material law with temperature dependent parameters has been developed.

Highlights

Additive Manufacturing (AM) is becoming an important technology as it provides the production flexibility and part geometry complexity
Eheat = αPheat∆theat where ∆theat is the heating time, Pheat the heating power and α the powder absorption parameter. This parameter is taken so that the reached nodal temperature is higher than the melting temperature. ∆theat is proportionnal the interaction time with powder, ie the time the laser spends to cross its own diameter
Material law The mechanical state is updated by incremental resolution, locally at each Gauss point in each element

Summary

Introduction

Additive Manufacturing (AM) is becoming an important technology as it provides the production flexibility and part geometry complexity. Numerical simulation is developed to model the physical phenomena in the process. At the part scale, modeling is more interested in the thermal and mechanical phenomena including stress evolution and final deformation. Macroscopic approach and 3D finite element method are preferred in order to achieve whole part simulation in an affordable computation time. A finite element model for the simulation of additive manufacturing is developed.

Results

Conclusion