Laboratory for materials physics

In the Laboratory for Materials Physics, investigations are carried out on metals with regard to their microstructure-property correlations, which are obtained by measuring internal friction (damping). The internal friction of a metal depends among other things on:

  • the degree of purity
  • thermal and mechanical treatment [1]
  • the number of load changes
  • the time of measurement after a load

Head of Navigation Laboratory: Prof. Dr. rer. nat. Jürgen Göken
Team Navigation Lab: Sarah Fayed, M. Sc.
The navigation lab is located in room B22.

Tests on metals in the laboratory for materials physics

This figure shows the result of strain-dependent damping measurements (measured as logarithmic decrement δ) on a metal foam made of aluminium. It can be seen that a significant increase in damping occurs for low strain amplitudes as the vibration frequency N increases ε The increase in damping is due to crack initiation or crack growth. Measurements of this kind are interesting, for example, for components that are subjected to cyclical continuous loading.

 

The investigations in the Laboratory of Materials Physics aim to precisely measure and predict the damping properties of a metal and, as a result, to expand the areas of application of high or low damping materials, see figure.

 

In addition to basic research in materials physics, special measurements are also carried out in the following industrial sectors to determine the damping of materials for application:

  • On- and offshore industry
  • Shipbuilding industry
  • Automotive Industry
  • Aviation industry
  • Music industry

For example, highly damping metals must be used if vibrations in machine components or other parts (ship propellers, rotor blades, ...) are to be reduced to increase service life and reduce noise.

In order to reduce noise, the Laboratory for Materials Physics also has a measuring system for sound localisation ("acoustic camera"). With the help of this sound localization measuring system it is possible to visualize the location of the sound origin. This allows targeted design or material-specific measures to be taken to reduce critical vibration amplitudes. This is accompanied by a reduction in noise, as is desired on passenger ships, for example. However, the field of application of this sound location measurement system is much wider, as too high sound pressure levels occur in a wide variety of areas in working life and can pose a considerable health risk.

The figure shows sound localization measurements on different objects. The red areas represent the area of highest sound pressure, while the blue areas represent reduced sound pressure. Thus mechanical loads on the object can be determined without contact.

In addition to the measuring equipment listed above, the department, which is mainly involved in maritime technology, has photogrammetry equipment installed in the department's test basin. This enables the dynamic behaviour of the ship to be correlated with the wave characteristics [4].

[1] Göken, J.; Maikranz-Valentin, M.; Steinhoff, K.; Pavlova, T.S.; Ivleva, T. V.; Golovin, I. S.: Change of Structure and Properties of 51CrV4 Shaft Caused by Thermo-Mechanical Treatment. Solid State Phen. 137 (2008) 169-180.

[2] Golovin, I.S.; Sinning, H. R.; Göken, J.; Riehemann, W.: Mechanical Damping of Some Al Foams Under Cyclic Deformation. In: Banhart, J.; Ashby, M. F.; Fleck, N. A. (eds.), Cellular Metals and Metal Foaming Technology. Verlag MIT Publishing, Bremen (Germany) 2001, pp. 323-328.

[3] Projekt „MariTIM“; INTERREG IV A-Programm (http://www.maritim-de-nl.eu; Stand: Mai 2014).

[4] Göken, J.; Wolf, B.-M.; Luker, S.; Meenken, E.: Messung der Schiffsbewegung mittels Photogrammetrie. HANSA International Maritime Journal, 3 (2010), S. 24-26.