Well protected: bionic lightweight design equipment containers – inspired by nature
Lightweight materials are clearly the building material of the future. With growth in demand of several 100%, they are setting economic standards.
Lighter, safer, standardised
Five research institutes and companies from the capital region have joined forces to build equipment containers that are unique in the world. New joining technologies and extremely lightweight hybrid laminates play an important role in their endeavours because they can do just about anything conventional materials cannot do. Knowledge, experience and a spirit of innovation converge in this project.
Watch out, this place is packed full of shortcuts! The jargon used by developers, project supervisors, process optimisers and controllers and their respective institutions is often littered with abbreviations. This simplifies the internal as well as the external communication during complex projects. Abbreviations help to ensure that Excel tables are not completely blown out of proportion. They make it easier to see the whole picture. Last but not least, they convey competence and expertise to the outside world – and sometimes they also just look nice. Let us take LFT as an example. It stands for: “Lehrstuhl Füge- und Schweißtechnik” (Academic Chair of Joining and Welding Technologies) at the Brandenburg University of Technology Cottbus-Senftenberg – the unabbreviated version does not run of the tongue easily, does it? The logo of the LFT changes that. It shows a strong bright red “F” in-between two grey metal-like letters. It represents firm joining and welding technologies. Joining techniques – in particular the ones that shape objects – represent crucial production steps during the manufacturing of components, which can withstand high loads. This is also of particular importance in the joint research project LGS of the Federal Ministry of Education and Research that is being carried out by these five partners: LFT, LsW, KSC, PLE and TGM.
But hold on; let us go back to the beginning! What is the problem that needs to be solved?
Unique equipment containers
Air conditioning systems, batteries, transformers, brake controls or gas tanks need safe housings. They must be protected from external hazards such as stone falls and temperature changes and from all kinds of accidents. Containers that accommodate small and larger units exist for this purpose; they protect, for example, air conditioning systems in trains or batteries in electric buses. So, the problem is that transport vehicles such as buses, trains or ships consume energy and it would be great if it was possible to reduce this energy consumption. A heavy object requires more energy to reach a certain speed. It’s basic physics. And here’s the solution: weight reductions through lightweight components. The second problem is safety. An insulating layer made out of a heat-insulating material may very well be heat-insulating, but it does not necessarily protect against sudden impacts or even crashes. The solution: a single material that combines two properties and therefore insulates and is sturdy at the same time. Chaos is the third problem. Supplier A offers cheap containers at a certain price, but they don’t fit. Supplier B offers suitable and even relatively inexpensive systems that, however, do not match the neighbouring modules. Supplier C offers suitable containers for Chinese electric buses, but not for American ones. And so on. And here’s the solution: a modular system that works worldwide and sets standards.
Lighter, safer, standardised: the “Modular Lightweight Design Equipment Container System” (Leichtbau-Gerätecontainer-System, LGS) combines all of these features. It is currently being developed in Brandenburg. The project started in September 2016 and the first industrially utilisable results should be available in February 2019. Five project partners are on board; they carry out different tasks and they all want to highlight the opportunities that “lightweight design made in Brandenburg” has to offer. And now back to the abbreviations.
Here are all of the partners and their respective tasks
- LFT / Lehrstuhl Füge- und Schweißtechnik (Academic Chair of Joining and Welding Technologies) at the Brandenburg University of Technology Cottbus-Senftenberg
Testing concepts and FEM-based process and analogous models (FEM = Finite Element Method)
- LsW / Fachgebiet Leichtbau mit strukturierten Werkstoffen (department “Lightweight Design with Structured Materials”) of the Brandenburg University of Technology Cottbus-Senftenberg
Design and integration of hybrid structured multilayer composites
- KSC / Kraftwerks-Service Cottbus Anlagenbau GmbH
Development of additively manufactured connecting nodes and of adhesive joining concepts
- PLE / Photon Laser Engineering GmbH
Production concepts for laser beam welding of hybrid structured multilayer composites
- TGM / Lightweight Solutions GmbH
Development of lightweight design thrust field concepts and calculation routines for their design
Bionic and elastic – nature’s lightweight design provides the inspiration
It is clear: these are complex tasks. But what are they all about? KSC is responsible for the “additively manufactured connecting nodes and adhesive joining concepts”, but what are they? Putting it simply: the individual components of the container have to be joined together – and this is why special adhesive elements are needed. Erik Dietz, project manager at KSC, is currently researching the optimal material and structure for connecting nodes made out of plastic and metal. Bionics can help with that and Dietz is therefore learning from nature, which has been pulling invaluable inventions out of its sleeve for millions of years. We just have to find them. Here’s one example: honeycombs or microcellular structures just as the ones in beehives are elastic and extremely resilient at the same time. And they are also light. Spiders use fine threads to catch their prey. Their nets are delicate, almost invisible, yet they defy wind and weather.
This is what Dietz wants to achieve. Once he finds the material, it will go into additive manufacturing and the printing of geometrically complex objects with the help of a 3D printer will commence. The pulverised substances are then applied to a plate and melted by a laser beam. The component, which has been designed on a computer, will be created by “welding” it layer by layer. The laser technology and its applications are described in more detail in a working paper, which Dietz compiled together with his cooperation partners from the Brandenburg University of Technology Cottbus. Here is an excerpt:
“Selective Laser Melting (SLM) offers new possibilities and complements conventional manufacturing technologies, especially when formative or subtractive manufacturing processes, such as casting or milling, reach their limits. However, its wide use in series production must still overcome a number of obstacles. For example: the user faces uncertainties when it comes to the implementation, e.g. with regard to choosing a suitable manufacturing strategy, the design of the supporting structures or the hatch definition, which has a non-negligible influence on internal stress and component distortion. Irrespective of these obstacles the application of additively manufactured components has a huge potential for development and offers the opportunity to implement new lightweight design concepts. Thus, new design criteria for lightweight design frame elements, which are conventionally manufactured as rigid frames and non-load-bearing coverings (differential construction), can be implemented. New approaches pursue the use of the thrust field concept, which is successfully being used in the manufacturing of aircrafts. The corner connections of the frame structure are of particular importance in this regard because their load path has to be optimised and they must be adapted to the respective loads in order to ensure a targeted load line between the thrust field and the frame structure.” (source: “SLM gefertigte Verbindungsknoten für Leichtbaurahmenelemente” [“Connecting nodes for lightweight design frame elements manufactured through SLM”], 2018)
Erik Dietz is confident that he is on the right track with this new technology. “This expands our expertise in the area of 3D printing,” he says. It is something that is really not without importance for a company in the middle of a so-called “area transfer”. KSC currently has 170 employees. It generates almost half of its turnover through activities and products that belong to an era that will end in the foreseeable future. “So far, our company has focused strongly on services related to power stations, and we intend to continue offering our know-how in this field in the future as well. In addition, we want to diversify and expand our portfolio and our know-how. We are working very closely together with Hans Rüdiger Lange and the Innovationsregion Lausitz GmbH. All of this requires initial investments, but it offers long-term opportunities.” If the LGS project opens up new areas, new jobs can possibly be created. “This depends on how the new product will be accepted by the customers once we’ll start the series production of the lightweight design equipment container together with our cooperation partners. The new business area will primarily enable us to proactively accompany the current structural change and to sustainably preserve existing jobs.”
This is where politics comes into play. Politicians have recognised the potential of this technology for Lusatia. The Federal Ministry of Education and Research is supporting the project partners with altogether EUR 1.8 million. “The state government as well as the federal government are very eager to promote the structural change in the region and to create the necessary framework conditions provided that the region wants to be proactive,” explains Dietz. “The aim of the project is to enable small and medium-sized enterprises to develop new know-how and to create new business areas.”
That sounds really good. What experiences has Dietz gathered during the cooperation with the project partners so far? “This is indeed our first research project, but it will certainly not be our last. Based on the positive experiences made with our industrial partners so far and on the high added value of the knowledge and technology transfer between the department LsW and the academic chairs LFT of the Brandenburg University of Technology, we want to continue on this path and actively support other future research projects as well. The first plans are already in the top drawer.”
The project has already passed its first acid test. A prototype of the LGS was presented at the InnoTrans in September 2018. The international trade fair for transport technologies was the ideal place to address potential interested parties in a targeted manner. The goal of achieving weight savings of altogether up to 20% was well received. And some visitors had heard of bionics before.
The general vibe at the fair: lightweight design is a topic that affects the entire sector. The trade fair prototype, which was on display at the stand, led to further inquiries and a prototype will be provided for a one-year or multi-year real-life test on the roof of a tramway. This raised the question: What are our trams actually made of?
We can still do a lot more!