Aus Wissenschaft und Forschung / TAE-Plenarvorträge 42 Tribologie + Schmierungstechnik · 67. Jahrgang · 4/ 2020 1 Introduction Within the presentation, the Young Tribologists want to address the following questions: • How are we affected by tribology in our professional environment? • How are we affected by tribology in our daily life? • How would these questions be answered by young tribologists from other parts of the world? 2 Mirjam’s view on Tribology One of the descriptions of tribology from Horst Czichos is very popular: Tribology is an interdisciplinary field, which helps to optimize mechanical technologies by reducing energy and material losses with reduction friction and wear [1]. In the past, this context was often related to the gross social national product, which is influenced by energy and material losses of up to 4.5 % per year in Germany (35 bn. euros per year). In the last years, another aspect gets more into the focus of societal understanding: energy and material losses are also related to the necessity environmental conservation e.g. protecting the climate. In this context, two main issues can be derived: 1. How can future tribological systems be designed so that the whole lifetime - cradle to cradle - will experience as few energy and material losses as possible while simultaneously fulfilling any other requirements on the tribological system within the integrated system? 2. Which new requirements of modern tribological systems then result? Answering these two questions results in very complex and interdisciplinary cooperation, but in first step, the main task of tribologists is to communicate the potential of tribology to save our environment and to support other fields that work on this subject. Therefore, it is very necessary to quantify this potential. This year, the German Society of Tribology (Gesellschaft für Tribologie e.V.) took a first step in quantifying the impact of tribology solutions on CO 2 emissions and further environmental aspects, e.g. particulate matter and e-Mobility [2]. In this context, I would like to relate my professional activity to the question of environmental conservation. Of course, the following approach is very idealistic, because on the one hand industrial developments are always pushed by costumer requirements, which is why application-specific research is complicated. On the other hand, platform strategies lead to lower development costs. That’s why the optimization potential of tribological systems is limited, because platform strategies always require equivalent tribological systems. In the end the market is driven by competition. That’s why we are faced by the fact that a lot of tribological potential is known and can be quantified internally in companies but cannot be published in any way. It’s also why it’s only possible for me to give a rough example, which is my contribution on environmental conservation by doing my job at Magna Powertrain. At our company location, all-wheel-drive systems and axles are developed, including the development of systems for e-Drive powertrains. One of the main requirements of the e-Drive systems is high efficiency. Conventional technologies quickly reach the limits of technical feasibility, which is why, during development, a high degree of innovation is necessary. One example in this context is the development of innovative eDrive fluids, because some of these fluids lead to very good efficiency. Another example is the adjustment of the right system viscosity related to operating conditions, because the right viscosity characteristic has one of the most important impacts on load independent and load dependent How Tribology Grows Further and Further Mirjam Bäse, Florian Rummel, Hitoshi Washizu, Vlad Bodgan Niste, Stephan Henzler, Rebekka Drafz* * Mirjam Bäse Magna Powertrain GmbH & Co KG, Lannach, Austria Florian Rummel Anton Paar GmbH, Ostfildern, Germany Hitoshi Washizu University of Hyogo, Hyogo, Japan Vlad Bodgan Niste Kyushu University, Kyushu, Japan Stephan Henzler Carl Bechem GmbH, Hagen, Germany Rebekka Drafz Fuchs Schmierstoffe GmbH, Mannheim, Germany Aus Wissenschaft und Forschung / TAE-Plenarvorträge 43 Tribologie + Schmierungstechnik · 67. Jahrgang · 4/ 2020 power losses. In contrast to these optimization possibilities, requirements e.g. wear protection, material compability and clutch performance over the whole life time have to be taken into account of the lubricant development. Currently, innovative eDrive fluids do not fully meet those requirements. To perform the previously mentioned tasks, which tribologists have to do first: My task, is in this context, to communicate the efficiency increasing potential of such innovative fluids in our systems within our company and show the limits of those fluids. And the second task is to interdisciplinarily work together with other departments, as well as with our suppliers and scientific institutions to find solutions for applying those innovative fluids in our systems in the near future, followed by working out realistic requirements on the newly developed eDrive fluid. The potential for reducing energy and material losses can be subsequently quantified very clearly. If those innovative eDrive fluids were produced from reusable raw materials and renewable energy, further energy and material losses could be prevented. But, and this is just one of many criticisms: those requirements haven’t reached the industry yet, which is why they are not focus of our development. But I also have to criticize myself, because in fact my statement needs a certain amount of authenticity and privately, I am also not very consistent on environmental conservation. I also fly to other countries for holidays and sometimes use my car for longer distances. But I do my best and would like to appeal in this context to anyone in our community: we are responsible for our environment because of our children, but also because we are working in the field of tribology. 3 Florian’s view on Tribology Tribology is present in our daily life, e.g. when we enjoy wine and chocolate and need to brush our teeth afterwards. In sports, tribology plays a crucial role: imagine a pole vaulter or a climber who stands on a small step, both seeking very high friction between the hand and the pole or the shoes and the rock, respectively. If our body degrades or is injured, either in an accident or by diseases, tribology is there to help us: Damaged or degraded cartilage may show poor tribological performance and maybe subject to revision, either by total joint endoprosthetics or with the help of artificial tissues and hydrogels, which are currently of great interest in biomedical research [3]. Further medical devices such as catheters, implants, medical needles [4] or pharmaceuticals like eye drops can be optimized through tribology, helping us to improve quality of life. What might be expected from people from different places around the globe can be influenced by various sociodemographic and educational circumstances. Countries with a history in automotive or aviation such as Germany or the United States may also have a distinct history in conventional tribology. Other countries with highly specialized companies such as Switzerland can use their potential to work in niches and other wealthy countries with ageing population may put special emphasis on the development of implants to ensure a high life quality for their citizens. In my work at Anton Paar, I am responsible for tribology applications in various fields. Together with our partners, I develop experimental approaches for tribological testing. Typical applications are in conventional tribology such as lubricants, polymers or coatings. The working environment is characterized by an international and highly dynamic nature, involving discussions with different parties such as software and firmware development, product management, product engineering and sales. The most relevant goal is to make sure that Anton Paar offers a solution to best serve the customer’s needs and, if required, also make changes to our system, e.g. by designing special adapters for specimen or samples. Some applications are complex and need to be solved within cooperations between Anton Paar and partners from academia and industry. 4 Hitoshi’s view on Tribology Ecology and economy sometimes conflict with each other. Even if each person is concerned about ecology, it is very difficult to choose ecological products from many products with price competitive power. The first commercial hybrid vehicle went on sale in 1997. The importance of the event was the customer chosen high price car rather than low price and less ecological cars. From the practical point of view, the environment will never be protected by a huge number of discussions or research papers, but ecological commercial vehicles will really affect the protection of the environment. As a tribologist, however, this situation is very hard. The engine of the vehicle suddenly stops in the hybrid system. This means the relative time spent in boundary lubrication becomes dominant in all machine elements. To overcome this difficulty, tribologists have taken great strides to reduce friction by surface coatings, texturing and making new additives for engine oils. Aus Wissenschaft und Forschung / TAE-Plenarvorträge 44 Tribologie + Schmierungstechnik · 67. Jahrgang · 4/ 2020 The most serious subject in mechanical engineering in the 21 st century is how to design machines. Computer aided design, such as topology optimization may be a powerful tool. The other way is to design from nanoscale. We attacked this problem of nanoscale mechanical design using molecular simulation and found the origin of kinetic friction [5], the ultralow friction mechanism of layered materials [6], the origin of limited shear stress in elasto-hydrodynamic lubrication [7] and now we are attacking the problem of boundary lubrication [8]. Friction reduction may be achieved by more than a single technique. This is why we are challenging many tribological phenomena using molecular simulations. 5 Vlad’s view on Tribology The energy requirements of our modern society have led to a substantial output of carbon dioxide emissions on a global scale. In our goal to remedy the situation, there is a worldwide initiative to develop an environmentally friendly and carbon-neutral society based on renewable resources and reliable energy carrier systems. Substantial investments have recently been made toward a hydrogen-powered society, in conjunction with renewable energy sources, to provide the required energy that is stored for later use. This objective relies on applications like wind turbines, engines, compressors, reactors etc., which contain various tribological components, such as rolling element bearings, valves and seals. These are often essential and their performance can be the limiting factor of product lifetime. However, due to the constant improvements in material properties, they are subjected to ever more severe mechanical stresses and the presence of hydrogen. These issues are likely to be a main focus of future research in tribology, as renewable energies gain an increasing fraction of world energy production. 6 Rebekkas’s view on Tribology As mentioned before, tribology is an interdisciplinary field. In the automotive industry, the pressure is constantly increasing to develop and implement ever more efficient technologies, which at the same time are as environmentally friendly as possible. Efficiency plays a decisive role in all applications. In my current work in the field of lubricants, there is great potential, not only for oil application (transmission fluids), but also for greases, e.g. for wind turbines. Quite early during my studies I came into contact with the variety in the field of tribology, whether it’s mimicking the gecko effect, which relies on a dry adhesion mechanism or friction and wear in polymer-metal pairings. Tribological systems are very complex. The systems to be considered consist of many individual building blocks that make up the overall system. On the other hand, tribological phenomena occur on different size scales, which are subdivided into nano-, microand macroscale. Even if the problem is predominantly on the macro scale, you need deeper insight down to the na-noscale to find a solution. In my experience, the point of view of one discipline is not enough. That’s why the work of the Young Tribologists to bring different disciplines together is very important. This is about the exchange of different perspectives. All of them are needed to get a solution for one problem. The diversity of the different disciplines (natural sciences and engineers) is of crucial importance. 7 Stephan’s view on Tribology Tribology affects us in the morning after getting up using an electric toothbrush and turning on the water tap, where lubricants provide pleasant acoustics, haptics and durability. Or if the tram makes noise due to the wheel to rail contact, because no rail lubrication has been installed yet. These everyday examples also illustrate the first trade-offs. Haptics, acoustics and durability are important to many users and at the same time, the resources and technologies, which are used, should not endanger the environment. In order to meet these “requirements”, a high degree of tribological expertise is necessary. Through my work as a technology manager, I face new challenges every day, especially in the automotive sector. Just to name two keywords: • Electro mobility • Vehicle interiors of the future By changing the load spectrum, such as in rolling bearing speeds for electro mobility, new materials and lubricants for rolling bearings become necessary to achieve the life-time requirements. This also leads to a reevaluation of wear mechanisms and resulting system malfunctions and functional failures. The sensitive behavioral responses of vehicle interiors are also developing steadily, which will lead to new specifications for the acoustics, haptics and odor emission of the interior. Therefore, it is not surprising that today leather seats are coated with anti-friction coatings to avoid creaking or Aus Wissenschaft und Forschung / TAE-Plenarvorträge 45 Tribologie + Schmierungstechnik · 67. Jahrgang · 4/ 2020 groaning noises between the seat and backrest (stickslip). The increasing number of adjustment mechanisms and switches and the requirements for the haptic is often only possible by using lubrication. However, at the same time new limits for the evaluation of the odor emissions defined, with increasing necessity of lubricants in the vehicle interior. Presumably, the so-called “New Car Smell” will disappear in the near future. My daily task now is to incorporate these challenges into new or further developments. In addition, I am responsible for the further development of measuring methods to characterize tribological and technical issues and implement all results and findings in new product developments. The aim is to achieve the maximum system performance with a minimal amount of grease, for example, in order to save resources and to keep the environmental impact as low as possible. Unfortunately, it is very difficult to comply because of new requirements frequently defined by the OEM´s, as well as the simultaneous redefinition according to the requirement “fit for purpose”. 8 summary and outlook The perspective on and of tribology and the spectrum of related subjects are as varied as the tribologists themselves and we have just begun to explore this exciting field more deeply since its official foundation in 1966, when Peter Jost defined the field of tribology. We all, as tribologists, can effect many positive changes - whether in industry or in medicine. We just have to follow the right trend - not least to continue to further educate those involved in fields with tribological implications. We to continue the discussion on which trends require the strongest focus in the future. References [1] Czichos, Habig: Tribologie-Handbuch, Vieweg Verlag, 1992 [2] Woydt, M.; Gradt, T.; Hosenfeldt, T.; Luther, R.; Rienäcker, A.; Wetzel, F.-J.; Wincierz, C.: Tribologie in Deutschland - Querschnittstechnologie zur Minderung von CO 2 - Emissionen und zur Ressourcenschonung. Hrsg: Gesellschaft für Tribologie e.V., https: / / www.gft-ev.de/ wp-content/ uploads/ Studie_komplett.pdf [3] Kumru et al.: Polymer grafted graphitic carbon nitrides as precursors for reinforced lubricant hydrogels, Polymer Chemistry, 2019. [4] de Beer, Sissi: Lubricious coatings for precision positioning of medical needles, Leeds-Lyon Symposium on Tribology, 2019. [5] S. Kajita, H. Washizu, T. Ohmori, EPL (Europhys. Lett.), 87, 6, 66002(2009). [6] H. Washizu et al., Faraday Disc., 156 (1), 279 - 291, (2012). [7] H. Washizu, T. Ohmori, A. Suzuki, Chem. Phys. Lett., 678, 1-4 (2017). [8] M. Konishi, H. Washizu, Trib. Intl., DOI: 10.1016/ j. triboint.2019.01.027 (2019).