Simulation Benefits from Additive Manufacturing

04-10-2017 | Posted by Principia

No, there is no mistake in the order of the title. A more expected title might have been: “Additive manufacturing benefits from simulation”. Indeed, a major goal of simulation is to predict the distortions and residual strains caused during manufacturing processes.

But today we want to highlight the reverse: the momentum provided to simulation by the additive manufacturing of functional parts, a momentum that leads to improvements in general capabilities and benefits more traditional applications unrelated to additive manufacturing.

Many structures have geometries that evolve while being built or manufactured. An example is the construction of a concrete dam, which consists of the successive pouring and curing of layers of concrete; or the construction of a tunnel, characterised by the addition and removal of materials during the many phases of construction.

When dealing with such structures, traditional simulation techniques use models that are both inefficient and often overly complex. This situation has improved thanks to some of the tools developed for modelling additive manufacturing. These tools, such as event tables, involve simpler descriptions of processes, thus allowing more accurate analysis.

Many advances have been fostered by additive manufacturing and other technologies benefit from them as much or even more than additive manufacturing.

Materials modelling is another critical issue in additive manufacturing. This is particularly true when working with metals because their thermal memory leads to phase changes (including various forms of their polycrystalline structure) and porosity changes that have a drastic impact on their thermal and mechanical properties, and overall durability. The simulation of traditional thermal treatments, and other more general high-temperature scenarios, is also benefitted by such advances.

Furthermore, in additive manufacturing the material is incorporated with a mobile energy source, which in general is distributed over a certain volume. Goldak’s model, proposed more than 30 years ago in the context of welding processes, is now newly relevant as a consequence of developments in modelling additive manufacturing.

Another contribution is related to reusing the analysis results in a CAD code and, more specifically, in reconstructing geometries produced in a topological optimisation process. Those results typically take the form of a tessellated geometry but must then be returned to a parameterised description, traditionally by a manual process.

Additive manufacturing maintains a close relation with topological optimisation, as it eliminates many restrictions that other manufacturing processes impose on the design space.

This has led to the creation of automatic or semi-automatic tools for generating CAD geometries, thus advancing the development of many other products that require optimisation. Also, tools have been devised for automatic correction of the distortions that result from the simulation by modifying the original geometry.

All these advances have been fostered by additive manufacturing and other technologies benefit from them as much or even more than additive manufacturing. Hence it has become difficult to be up-to-date in general simulation capabilities without keeping a close eye on developments for additive manufacturing.