Electric drives: better magnetic material through fe-simulation

With the advent of electric drives, the question arises as to whether raw materials are available for the new applications. Only in april did the institute for future­techno­login and technology evaluation a study publishes, after some metals could be scarce in the long term.

For similar findings also comes a research team at the university of applied sciences st. Punch. That’s why you are looking for a research project under the direction of prof. Thomas schrefl to reduce the need for magnetic materials for electric drives. Because the materials used for high-performance duration magnets require a high proportion of rare earths, which are scarce and expensive. According to the university, an electric drive contains about two kilograms of magnetic material. The foundation currently form neodymium iron drilling magnets that have a far smaller mass compared to common magnets, but provide the same performance. In order for the magnetic properties to be obtained despite the high temperatures in an electric drive, the rare earth element is subsequently replaced by the rare earth element dysprosium.

According to the researchers, this increases the so-called coercive field of the magnet, which describes the stability of a demagnetization. According to prof. Schrefl there is a problem: the dysprosium share in the ore is less than 10 percent in the ratio to neodymium. However, the current high-performance magnets for electric drives were included a dysprosium content of up to 30 percent. This results in a raw material problem in the long term, the more electric drives prevail into cars.

In cooperation with the universitat sheffield wants the fh st. Polt in the project "green cars" now find out how the dysprosium share will decrease. Without reducing the temperature stability of the magnets. The researchers of the finite element method serve themselves. Prof. Schrefl: "we build the magnet in the computer and disassemble its granular structure in finite elements. Due to the decomposition of the microstructure in millions of tetraders and prisms, it is possible, the room distribution of metallic phases within the magnet in the computer­model. This allows the effect of changing the dysprosium content to the coezertive field of the magnet on the computer can be simulated."

The finite element method, short of fem, was created at the end of 1950s and has established itself in automotive construction, for example, for strength calculations of body structures or mechanical components. It is based on the fact that the surface of the complex object is decomposed into the smallest polygone elements, which can be calculated individually better. The increased computing power of today’s computers makes it possible to increase the "granularity" of the models, so today complex tasks can be calculated in a short time.

Leave a Reply

Your email address will not be published. Required fields are marked *