Regensburg 2002 – scientific programme
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SYME: Mechanical Properties of Thin Films
SYME 1: Elastic Properties
SYME 1.3: Talk
Monday, March 11, 2002, 16:15–16:30, H 31
The applicability of laseroptical sensors for strain measurements of thin structures — •Peter Zimprich1, Viktor Groeger1, Brigitte Weiss1, Golta Khatibi1, and Bernhard Zagar2 — 1Institute of Materialphysics, University Vienna, Austria — 2Institute for Electrical Measurements, University Linz, Austria
A new laser-speckle extensometer for determination of strain data with a displacement resolution of about 100 nm is presented. The system is based on a non-contacting laseroptical sensor using the digital laser speckle correlation technique, tracking the movement of the laser speckle pattern related to the granular structure of the illuminated surface element on the specimen. Because of the fast signal processing (reinitialisation), the data aquisition time can be varied from 2 s down to 40 ms. The strain resolution for the presented setup is better than 10-5 depending on the testing parameters. The system was designed especially to evaluate e.g. Youngs Modulus or thermal strain data of thin structures like films, foils, fibres and wires. This sensor is adaptable to commercial tensile testing machines or furnace equipments due to its simple optical setup. The physical principles as well as the technical requirements will be discussed shortly and some typical applications in materials science like investigations on metals, polymers, and multilayer-structures will be shown.