Abstract
Videoextensometry is a new experimental technique for non contact strain measurement, which enables measuring of longitudinal and transversal strain components on a planar surface of a loaded object. Experimental equipment uses a CCD camera (640 x 480 pixels) for monitoring the process on a surface area of 20 x 10 mm². The special software calculates the displacement of contrast dots prepared on the specimen surface. The paper presents results obtained experimentally on two steel grades for automotive steel sheet during tensile testing at different strain rates in the quasi static loading range. Non contact strain measuring is used for monitoring the strain development and strain localization.

Key words
microalloyed steel, interstitial free steel, deformation

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