Complex experimental-numerical evaluation of material mechanical behaviour using Digital Image Correlation method

0454101 - ÚTAM 2016 RIV CZ eng D - Dizertace
Jandejsek, Ivan
Complex experimental-numerical evaluation of material mechanical behaviour using Digital Image Correlation method.
České vysoké učení technické v Praze, Fakulty stavební. 16.12.2015. - Praha: ČVUT, 2015. 105 s.
Grant CEP: GA ČR(CZ) GA15-07210S
Institucionální podpora: RVO:68378297
Klíčová slova: Digital Image Correlation * experimental measurement * elastic plastic fracture mechanics * J-integral * CTOD
Kód oboru RIV: JL - Únava materiálu a lomová mechanika

The aim of this work is to develop an experimental methodology based on the Digital Image Correlation (DIC) method for the precise full-field in-plane stress-strain analysis in regions containing a stress concentrator. Several techniques and corrections were proposed and developed improving the conventional DIC and data post-processing to achieve high accuracy of full-field strain/stress results. It is shown that fracture parameters such as J-integral can be extracted directly from measured fields without the need of external FEM simulations. The optical nature of the DIC method also allows simultaneous measurements of CTOD and crack growth. The developed methodology is employed in the field of elastic plastic fracture mechanics to study fracture behaviour of ductile metals. The two particular experimental studies are carried out in this work. The first fracture test with a non-standard thin-sheet specimen made of aluminium alloy addresses the known problem of different fracture behaviour of thin-sheets, the second study deals with a fracture test with low strength steel commonly used in pipeline industry. The second test satisfied the ASTM standard for J-integral testing; therefore results of the proposed methodology are compared with the standard engineering approach. It was shown, that the ASTM standard gives non-conservative results. The fracture toughness of the tested materials in terms of the critical J-integral is determined in the both cases.
Trvalý link: http://hdl.handle.net/11104/0254829