The generation of electrical charges in response to mechanical deformation is a distinctive feature of piezoelectric materials. This property can be used to avoid mechanical stresses in special materials. A project currently funded by the Austrian Science Fund FWF will make a key contribution to the optimisation of these "intelligent materials".
High levels of mechanical stress reduce the lifespan of construction components. This is true for all types of materials; exposure to mechanical stress is a crucial factor in the duration of their lifespan. When stresses are combined with vibrations they have a particularly negative impact on durability.
Intelligent materials that can actively counteract such effects have been available for special applications for some years now. The solution applied here involves a very sophisticated trick of physics: the so-called piezoelectric effect, that is the generation of an electrical charge through deformation, can be used to actively suppress these forces.
However, piezoelectric materials are also subject to forces which reduce their durability and finding a way of changing this is the challenge that scientist Jürgen Schöftner has set himself.
VIBRATIONS AND STRESSES
A particular characteristic of piezoelectric materials plays a key role in Schöftner's research: "A distinctive feature of piezoelectric materials is their special combination of physical properties. This is responsible for the fact that an increase of mechanical stress can arise even if the mechanical deformation of the material, which was caused by external forces, has already abated."
Such local increases in stress have a negative effect on the durability of the material and Schöftner aims to reduce them. As he explains, he is entering uncharted scientific territory here:
"The research carried out in recent years in this field, which is known as 'structural control', focused mainly on the reduction of vibrations and deformations. These methods are so far well understood. However, the findings on the avoidance of vibrations are of no help when it comes to the avoidance of mechanical stresses. New methods are needed here and we plan to develop the basis for them."
The first stage of Schöftner's project involves the analysis of the so-called constitutive relations for piezoelectric materials. This will enable the deduction of formulations for possible stress suppression in the three-dimensional space. He will then also calculate the basic differential equations for the stress. The aim of these basic calculations is to find workable concepts for the suppression of stresses in so-called lean components.
PASSIVE REGULATION – ACTIVE ENERGY HARVESTING
However, Schöftner is looking even further into the future in his project: "Piezoelectric materials can actually be used to harvest energy. The kinetic energy of a component is transformed into electrical oscillations and, therefore, neutralised. If the piezoelectric material is integrated into an electric network, the charge generated through the mechanical deformation can also be transmitted to a suitable electrical storage medium."
The long-term aim is to design an electrical network for a particular vibrating piezoelectric structure which, depending on requirements, regulates a mechanical stress under a certain level or transforms the vibrational energy into electrical energy through storage. This would require a smart circuit which consists of an active circuit for the stress regulation and a passive circuit for the energy harvesting.
Ideally, the mechanical stress would be regulated from a critical stress level – otherwise, vibrational energy would be converted into usable electrical energy. However, some basic homework will have to be done before such systems become a reality. Thus, in his project, Schöftner is working on the optimal distribution of the electrodes, the sheet resistance and the electrical network in such a system.
"The potential offered by such passively controlled materials is huge – however, before they can actually be used, we must obtain some basic information about the optimisation of these materials. This is precisely what we are doing in this FWF project," adds Schöftner.
Jürgen Schöftner has been a researcher at the Institute of Technical Mechanics at the Johannes Kepler University Linz since 2011. He is an expert in modelling and control of mechatronic problems.
DI Dr. Jürgen Schöftner
Johannes Kepler University Linz
Institute of Technical Mechanics
4040 Linz, Austria
T +43 / 732 / 2468 - 6314
Austrian Science Fund FWF:
Haus der Forschung
1090 Vienna, Austria
T +43 / 1 / 505 67 40 - 8111
Copy Editing & Distribution:
PR&D – Public Relations for Research & Education Mariannengasse 8
1090 Vienna, Austria
T +43 / 1 / 505 70 44
Marc Seumenicht | PR&D - Public Relations für Forschung & Bildung
Researchers shoot for success with simulations of laser pulse-material interactions
29.03.2017 | DOE/Oak Ridge National Laboratory
Nanomaterial makes laser light more applicable
28.03.2017 | Christian-Albrechts-Universität zu Kiel
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
29.03.2017 | Materials Sciences
29.03.2017 | Physics and Astronomy
29.03.2017 | Earth Sciences