DETERMINATION OF STRAIN GRADIENT CHANGE INFLUENCE AT THE BORE EXPANSION TEST

1 SOBOTKA Jiří
Co-authors:
1 SOLFRONK Pavel 1 KOLNEROVÁ Michaela 1 ZUZÁNEK Lukáš
Institution:
1 TUL - Technical University of Liberec, Liberec, Czech Republic, EU jiri.sobotka@tul.cz, pavel.solfronk@tul.cz, michaela.kolnerova@tul.cz, lukas.zuzanek@tul.cz
Conference:
24th International Conference on Metallurgy and Materials, Hotel Voronez I, Brno, Czech Republic, EU, June 3rd - 5th 2015
Proceedings:
Proceedings 24th International Conference on Metallurgy and Materials
Pages:
415-420
ISBN:
978-80-87294-58-1
ISSN:
2694-9296
Published:
12th January 2015
Proceedings of the conference were published in Web of Science and Scopus.
Metrics:
151 views / 42 downloads
Abstract

The bore expansion test represents one of basic technological tests for determination preparation technologies influence on the maximal strain value. The most frequently it is used to determine material limit stage at comparison blanking and e.g. nonconventional cutting methods (abrasive water jet, laser and so on). Regarding the great development of contact-less optical methods for measuring deformation it is subsequently very suitable to use photogrammetry also at measurement and evaluation the bore expansion test. As an advantage there is e.g. very transparent graphical display of strain distribution around the bore without necessity to manually measure final bore diameter, information about strain change course during the whole test or also possibility to display strain gradient in any direction. On the other hand among disadvantages of contact-less optical deformation measurement is mainly purchase price, necessity of their precious adjustment before measurement (calibration of cameras, setting of shutters and so on) and also requirement for special surface treatment of sample (stochastic pattern). Within the experimental part of this paper there was measured the bore expansion test by contact-less optical system ARAMIS. For testing was used the deep-drawing material marked as DC05 with phosphating as a surface treatment which is commonly used in the automotive industry. The purpose was to find out for six different initial diameters (from 5 mm up to 30 mm á 5 mm) strain distribution around bore for the last stage before the crack and subsequently to evaluate strain gradient change in radial direction. After that final data were processed statistically and graphically, mutually compared to determine strain gradient change influence.

Keywords: Bore Expansion Test, ARAMIS, Photogrammetry, Strain Gradient

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