積層造形シミュレーション

Rapid heating and cooling in the Selective Laser Melting (SLM) additive manufacturing process generates large amounts of tensile residual stresses in the component. These stresses lead to part distortions and poor product performance. In most cases, distortions become more significant after cutting the part from the build tray and removing support structures. In this study, a complex topology optimized Gimbal Mount was considered for physical printing and finite element analysis of the print process. Th component was printed using Ti6Al4V material on an SLM machine and measurement points were taken on its outer profile. This data was compared with original geometry and simulation results. A good agreement was found between simulation and experimental results which was helpful in part development and establishing the technology.

Customer Papers

As additive manufacturing (AM) evolves to become a more viable production solution in terms of cost, quality, and time, the need for predictive simulation of the process grows as well. After testing several commercial offerings to see how well they could predict deformation of various parts, Abaqus was found to be the most promising option and chosen for a more in depth analysis. The scope of this particular project was to examine the effects of certain simulation choices – from basics (mesh, time stepping, element type) to unique AM convergence techniques (full/partial activation, expansion time constant, follow deformation, etc.). Hundreds of simulations were run in Abaqus with various permutations and the resulting response on the final deformation and stress state was tracked.

Customer Papers

Selective laser melting (SLM) leads to high cooling rates and correspondingly high residual stresses, which can distort the printed part on the printing platform and even lead to part cracking and consequent print failure. The temperature profile and cooling rates during the SLM process are influenced by the surrounding powder bed and building platform, which can act as a significant heat sink depending on part design and platform arrangement. The new functionality of the Abaqus additive manufacturing simulation framework allows for separate modelling of solid (laser exposed) material, powder bed (not exposed) and platform (not exposed), as well as evolving heat transfer surfaces for the AM part. In this paper we highlight the influence of the surrounding powder bed and platform on the thermal characteristics of the printed part.

Customer Papers

While significant progress has been made in the last few years, the reliability of Additively Manufactured (AM) parts is often less than desirable as they suffer from manufacturing defects and hence subpar strength and fatigue life. To address this challenge, numerical methods are sought to provide insight into the process and help accelerate progress in raising the quality of AM parts. In metal AM applications, assessing the amount of unfused powder, melt pool volumes, and metallurgical phase transformations is often of interest. In this work, we introduce a generic framework for assessing metallurgical phase transformations, building on a previously-developed general simulation framework for predicting temperature evolution, distortions, and residual stresses.

Customer Papers

The impetus of additive manufacturing (AM) technology in the last few years is significant. However, in many cases the reliability of the technology leads to parts that suffer from manufacturing defects and hence subpar strength and fatigue life when compared to parts manufactured with conventional technologies. Sustained experimentation is often required and computer simulations, like in many other fields before, are sought to provide significant insight into the process such that progress in raising the quality of AM parts can be achieved. This paper presents a sequential thermals-stress modelling approach of additive manufacturing processes of titanium alloy Ti-6Al-4V parts leveraging a new physics-based framework in a general-purpose finite element code (Abaqus).

Community News

In this paper, thermo-mechanical-metallurgical simulations of Ti-6Al-4V parts produced by SLM are validated against experimental measurements. The work involves the simulation of the SLM process and the prediction of location-specific microstructural features (such as grain size, morphology characteristics and phase fractions). A framework for more generally predicting the mechanical properties of printed parts is then presented. This involves the implementation of a novel mapping between microstructural quantities and tensile properties at each material point. The results demonstrate the potential that the powerful new features of Abaqus2017 have for simulating AM processes.

Customer Papers