Simufact Additive is a powerful and scalable process simulation environment for the first-time-right optimization of Metal Additive Manufacturing processes.
Simufact Additive is based on MSC´s proven MARC solver technology
Simufact Additive´s basic concept lays the foundation for a wide variability and scalability through different levels of details for the simulation results. Simufact Additive combines best approaches in one unique software solution.
We call this a multi-scaling approach:
Simufact Additive offers several calculation methods:
Additive manufacturing processes with metals are always complex time-dependent thermo-mechanical processes that require a correspondingly high simulation effort. In order to achieve practical results more quickly, we transferred the "inherent strain" method to additive production in the powder bed when developing the software.
The method of the inherent strains originates from welding technology and should also be used here to simplify and accelerate the calculation of complex welding processes. The basic idea behind this is that the complex thermo-mechanical history of the process ultimately introduces a typical non-elastic (i.e. non-reducing) strain into the component, the so-called inherent strain. If this strain is now known, the time-consuming time-dependent thermo-mechanical calculation can be omitted and the purely mechanical calculation is much faster.
This method has been proven to achieve excellent results in terms of distortion behaviour and also loading due to internal stresses. It is, therefore, the first choice for achieving practical results quickly, i.e. within minutes or a few hours.
The challenge of the mechanical method is now to achieve the typical inherent elongations of the process under consideration as elegantly as possible, i.e. quickly and reliably. One possibility would be to determine this again by a small-scale simulation of the exposure process. In addition to the time required, however, there are considerable uncertainties regarding the possible result quality, since the nominal but not the actual conditions of the real process are fully known and can also fluctuate. The calibration of the inherent strains on test specimens has therefore proven to be the best approach. No simulation, however good, can completely replace the result of a physical test.
A fast optimization algorithm calibrates the inherent strain values so that they lead to the deformations measured in the test in the simulation. These strain values represent the (individual) machine used, the material and also the process parameters used. This enables reliable and fast simulation even for complex additive components.
Correct calibration is essential to obtain accurate simulation results.
All important data and details for easy and fast calibration, regardless if mechanical, thermo-mechanical or thermal, are already predefined in the graphical user interface (GUI). This also includes the individual cantilever geometry, uniform and isotropic inherent strain, the measuring point, and the separation phase.
In Simufact Additive, users can adapt these calibration parameters to their requirements. Besides, they can calibrate their geometry concerning the spatially dependent process parameters.
User-defined calibration also allows importing user-defined geometries and including the base plate during calibration.
Simufact Additive offers for the first time the possibility not only to use a set of inherent strains for the entire build space but also to define a location-dependent matrix. This allows, for example, different ratios to be mapped on the sides and in the corners of the build space, but also in height.
This makes it possible to further improve the quality of earnings, especially in the case of heavily utilised build space.
The inherent strains can be calibrated automatically for a constant height in the x-y plane.
The purely mechanical method of the inherent strains has at least one possible disadvantage with all its advantages - it is no longer possible to gain an insight into the thermal processes, which, however, are decisive for the additive development process. Specific manufacturing problems may require an insight into the temperature processes, e.g. to set heat dissipating support structures or to evaluate the effect of a build plate heating system.
To enable this effect on the component level if required, we have developed a novel thermal calculation model on the element layer level in Simufact Additive. With knowledge of the essential machine parameters such as laser power, speed, and exposure strategy, the global temperature curve can be simulated during the construction process. Since the real efficiency of the melting process is generally unknown, it can be easily calibrated against a specified peak temperature. A physical test is not necessary.
The results are, for example, the peak temperatures reached, which enable the identification and evaluation of overheated and underheated areas. The user also can evaluate temporal heating and cooling rates, local temperature gradients and heat flows.
In addition to the proven purely mechanical Inherent-Strain method and the purely thermal calculation, Simufact Additive also offers a thermo-mechanically coupled calculation method. In order to derive mechanical quantities such as distortion and residual stresses in addition to the temperature curve, we have mechanically coupled individual calculation steps in Simufact Additive based on the thermal calculation.
As with the inherent strain method, calibration against distortion is also recommended here. In this way, the user avoids an overestimation of the distortion caused by the model. He uses the same cantilever model as for mechanical calibration. Here it is important to scale the thermal strains in the calibration to achieve the measured deformation result in the simulation. This allows the software to predict realistic stress levels.
The thermo-mechanical simulation is suitable if mechanical and thermal results are to be represented in a simulation. Besides, better prediction results can be achieved in special manufacturing situations than with the purely mechanical inherent strains. This is partly because this method takes into account the temporal influence of layers of different sizes, which is particularly important in the case of major changes in the layer surfaces.
According to the experience gained, the thermo-mechanical method is recommended e.g.
With this calculation method, distortions and manufacturing problems can be simulated which are not obvious in purely mechanical simulation.
Simufact Additive offers a Linux solver in addition to the Windows Solver. Thereby the software is now available for simulations on Linux computers for instance on high-performance Linux clusters. The operation of the software through the GUI continues in the Windows environment.
Thus, very large models or countless variants can be quickly calculated using strong parallelization.
Efficient use of metallic parts made by additive manufacturing requires the prediction of the part’s performance under various loading condition which is highly sensitive to the inherently heterogeneous location-specific properties of the underlying material. Accurate prediction and control of location specific material properties necessitates accurate knowledge of the underlying microstructure with robust integration with finite element tools.
For the prediction of the microstructures, Simufact will add further functionality to Simufact Additive allowing for transient simulation with linked microstructure. Simufact is collaborating with Materials Resources LLC (MRL), a leader in materials informatics. This collaboration brings to designers and manufacturers the location-specific microstructure effects via an integrated computational microstructure-informed response laboratory (ICMRL) developed by MRL that is used for calibrating and validated Simufact Additive. The insertion of the continuously growing processing, microstructure, and property databases for additively manufactured metals provides Simufact customers with a microstructure-informed modeling tool from powder processing to mechanical performance of a finished part.
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