Logistic, Mobility & Infrastructure

The turbine from the printer

Researcher: Dirk Herzog
Institute for Laser and Systems Engineering (iLAS)

A TU Hamburg project shows that metal aircraft parts created in a 3D printer are much lighter and can be manufactured faster than conventionally produced ones. They help save kerosene and reduce the CO2 footprint of aircraft.

At first glance, it's not obvious what this workpiece is: It is round, open on both sides and there are many holes on the surface. What makes the curious piece special is that it is a metal part made in a 3D printer that is about a meter in diameter. "It's part of an aircraft turbine," says Dirk Herzog, solving the mystery. "And in fact, it is one of the largest individual parts that have been produced additively, i.e. by 3D printing, using a laser process to date," explains the engineer, who is responsible for the project for the Institute for Laser and Systems Engineering at TU Hamburg. But it's not just the size that's astonishing: "Switching from conventional casting to the additive process reduces costs and weight by 30 percent. And that means that its use can save valuable kerosene and thus CO2."

Down with emissions

It is an important step for aviation to comply with the EU's Green Deal. It stipulates that transport emissions should fall by 90 percent by 2050 compared with 1990 levels, and the aviation sector is expected to play its part. One research initiative to develop fuel-efficient aviation technologies was the Clean Sky 2 program funded by the European Commission and the European aerospace industry, which gave rise to the MOnACO project in 2018. In addition to TU Hamburg, which researched the printing process, project partners include Autodesk, which is taking care of design optimization, and TU Dresden. Their experts are building a test rig with state-of-the-art instruments that they will use to validate and measure the flow data after production. The consortium is working closely with the engine manufacturer GE Aerospace in Munich.

In principle, there are particularly stringent requirements in aircraft construction. This also applies to parts suppliers and leads to long lead times and high costs. These challenges and the fact that a turbine center frame is not a rotating part made it an ideal candidate for additive manufacturing. Dirk Herzog's team, which collaborates with the Fraunhofer IAPT in Bergedorf for 3D printing, makes it possible to manufacture the part in one piece, so that 150 individual parts no longer have to be joined together at the end - as is usually the case. This reduces the lead time for the manufacturer from nine to two and a half months.

Micrometer-thin layers

The printing itself takes place in a sealed-off large container. "In a layer of metal powder, in this case a nickel alloy, a laser beam fuses the individual parts of the powder at over 1,000 degrees Celsius," explains Herzog. "The layer is only 60 micrometers thin and sinks after the process. The metal powder is again evenly distributed and the laser exposure allows the next layer to form." The process repeats itself countless times until the turbine part is printed after quite a few days of construction. "A major advantage of additive manufacturing is the freedom in design. Depending on the specification, it can be adapted and rearranged at any time. Air diffusers, curves, channels or grid structures, everything is possible. At the beginning of the project, we mainly tried out how far we could reduce the wall thickness to save as much weight as possible," explains Herzog.

The process used is not limited to aviation. It has been used for medical implants, for example, for some time. But it is in aerospace that the financial benefits of weight reduction are greatest. This is shown by a simple "rule of thumb," which states that in aviation, 1 kilogram of weight saved can save 1,000 euros in fuel costs. Over the lifetime of an aircraft, this corresponds to around 25 metric tons of CO2. In other words, much more than in the automotive industry, where calculations are completely different due to higher unit numbers: Here, savings of 100 kilograms are needed to achieve the same cost effect. Since energy costs have risen across the board, weight reductions are likely to have an even greater financial impact. Herzog explains: "This is also the reason why such projects are often initially tested for the aerospace industry. 3D printing has already become established for individual, smaller engine components such as injection nozzles. But perhaps in the future, large-scale printed components will also be installed in aircraft as standard."

The MOnACO project consists of a consortium of Hamburg University of Technology (TU Hamburg), Technische Universität Dresden (TUD) and technology company Autodesk. It is supporting General Electric AAT Munich in the development and manufacture of a large additively manufactured metal component - the Advanced Additive Integrated Turbine Centre Frame (TCF).

[Translate to Alternative:] Turbine

Buildings become adaptive


Researcher              Prof. Kay Smarsly

Duration                  2021 – 2024

Institute                   Digital and Autonomous Construction

School of Studies     Civil Engineering (B)

Smart buildings can already measure and analyze their condition with sensors. In the future, they will learn to behave sustainably and future-proof with the help of this data and the Internet of Things.

To cope with the consequences of climate change in the long term, the infrastructure with its cities, settlements and bridges must become resilient. Modern structures already carry many sensors inside them and measure and analyze their condition. Via these intelligent actuators, they actively adapt to the conditions of the environment. However, they are not able to learn from sensor-based structural and environmental data. The goal is to make them sentient and learning buildings by using the generated data autonomously with the help of the Internet of Things (IoT) in the sense of sustainable resilient behavior. For example, such a building "takes care" of its occupants by helping to optimize energy consumption and reduce costs.

Reducing carbon footprint

"The goal of this project is to use the emerging paradigm of cognitive buildings to develop a new scientific basis for resilient infrastructure. Cognitive buildings are able to detect environmental conditions, learn from external or user factors, and integrate IoT devices to optimize performance," explains Prof. Kay Smarsly. Buildings typically focus on reducing energy consumption and carbon footprint. However, they are not able to seamlessly integrate structural information relevant to resilience. This could be, for example, the impact of natural forces or environmental stresses that the building must withstand. As a starting point, condition monitoring and control strategies relevant to resilient infrastructure are considered. Until now, the practice has relied primarily on data-driven modeling to obtain information about building condition. However, data-driven modeling lacks a physical background and does not provide the information needed for this type of monitoring. Therefore, in this project, resilience-related strategies of structural monitoring (Structural Health Monitoring) and adaptive structures (Structural Control), such as load-bearing capacity or serviceability, in particular, are made usable wirelessly.

Feel, learn, adapt

This project provides a construction informatics-based theoretical framework that is designed to provide a universally applicable problem-solving approach to current and future societally relevant challenges in infrastructure and human settlement. It is assumed that by implementing cognitive building, resilient infrastructure can be built, widespread and sustainable industrialization can be promoted, and innovation can be supported. Applied to cities and settlements, they can be made safer, more resilient, and more sustainable.

Prof. Kay Smarsly supervises the DFG project "Resilient Infrastructure".