Naslov
Numerical model of corrosion influence on mechanical behavior of steel AH36

Autori
Pastorčić, Darko ; Vukelić, Goran ; Božić, Željko

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
ECF23 book of abstracts / Moreira, Pedro ; Reis, Luis - Funcha, Portugal : ESIS Publishing House (ESIS-PH), 2022, 146-146

ISBN
9788831482189

Skup
European Conference on Fracture 2022 (ECF23)

Mjesto i datum
Funchal, Portugal, 27.06.2022. - 01.07.2022

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
steel AH36 ; material degradation ; numerical analysis

Sažetak
Mechanical behavior of butt-welded joints made of AH36 shipbuilding steel exposed to corrosive environments is analyzed experimentally and numerically in this paper. Testing specimens have been cut out of butt-welded sheets in a way that they incorporate base metal, heat-affected zone and weld metal (BM, HAZ, WM). The specimens were exposed to real marine environment (water, sea water, sea tide) for prolonged periods (6, 12, 24 and 36 months) in order to determine the influence of the environment. In the experimental part of the research, after the specimens were extracted from experiment site, they have been tested to determine the change of the mechanical properties of the metal. Standardized tensile tests have been performed along with the Charpy impact tests. Moreover, the corroded surface was examined using optical and scanning electron microscopy. Results show deterioration of the mechanical properties of steel exposed to the sea environment. The most significant deterioration is noticed on the specimens exposed to continuous influence of the sea waves. As for the numerical analysis, the experimental results were base for development of the numerical model of the corroded surfaces. The corrosion pits for each zone (BM, HAZ, WM) were modeled using spatial Poisson process and Gamma process for the pit depth progress. The finite element model of the butt-welded steel specimen was developed in order to perform simulated tensile test using SMCS ductile fracture criterion with different 𝛼𝛼 parameters and hardening models for each zone. Because of the huge number of the finite elements, the submodeling was necessary to perform for each environment and the period of exposure. It is shown that with the increase of the stress triaxiality, i.e. average triaxiality, which depends of the pit size and distribution, critical plastic strain decreases. Consequently this leads to the earlier ductile fracture initiation and degradation of the mechanical properties. The numerically assessed results show good agreement with the experimental results. Additionally, since the numerical procedure is based on the real corrosive conditions (not laboratory accelerated), it can be used for further assessment of other types of welded steel exposed to the sea environment, particularly for EH and DH steels which are used for the naval and offshore structures.

Izvorni jezik
Engleski

Znanstvena područja
Strojarstvo, Temeljne tehničke znanosti

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