“As a PhD student at NLR, I work on topology optimisation techniques for aircraft components. Topology optimisation is a design technology that can be used to find an optimised design, without making any assumptions in advance about its geometry, form and topology. ‘Optimal’ can have differing meanings here, such as ‘minimum weight’ or ‘maximum stiffness’. This absolute freedom of design makes it a potentially powerful technology for optimising the weight of aircraft components. Among the concrete applications of topology optimisation for aircraft components are the ribs in aircraft wings and flaps. The technology has already been applied for this purpose in designing the ribs of the Airbus A380, but it could also be used for smaller components, such as various hinges.

However, the current optimisation techniques still have significant shortcomings. The challenge my research addresses is: how can the stresses and forces in a structure be taken into consideration in the topology optimisation process? This is not yet possible, which is why the design obtained with the current methodology still needs further adjustment. The optimised designs are often also complex and cannot be directly manufactured with conventional machining techniques, such as turning and milling. That means a designer is still required to interpret the optimised design and adapt it with a view to taking it into production.

Therefore 3D printing is an interesting development, as it builds up the product layer by layer, with virtually no constraints in terms of production. That is why I believe the development of 3D printing technology will make the field of topology optimisation even more important.

My research arose from the need to develop increasingly lighter aircraft that have lower fuel consumption and therefore lower emission levels, thus generating cost savings. Optimisation techniques are also highly interesting in that they can be broadly applied. For example, it could be used in aircraft design as well as food industry to minimise packaging material. Another example is Formula 1 racing, where cost savings are less important, but the main aim is to construct the car with the best performance.

I really like topology optimisation because of the freedom of design it offers and the beautiful forms it produces, which would be difficult to arrive at intuitively. It’s a matter of puzzling over formulae that depends on the specific optimisation problem, the underlying physics and the methods for solving the optimisation problem. One of the challenges in the optimisation problems I work on is that they often have several solutions (mathematical optima). This means that depending on the initial conditions, you may obtain different final designs.

NLR is an interesting place to work for anyone who is as intrigued by optimisation and mechanics as I am. Because this is a research environment, where you’re closer to real applications than at universities.”

Alexander Verbart is a PhD-student at the department of structural optimization and mechanics (som), Delft University of Technology.

“With the development of 3D printing technologies, my field is becoming even more important.”

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