PSI - Issue 52

Lucie Malíková et al. / Procedia Structural Integrity 52 (2024) 376–381 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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al. (2021), Xue et al. (2021) or Zheng et al. (2020). Some of the recent investigations made on the effect of corrosion on for instance elastic modulus, yield and ultimate strength showed a significant decrease of the mentioned mechanical properties values with the increasing level of corrosion. It has been also presented that existence of corrosion defects/pits leads to initiation of fatigue cracks, see e.g. Bastidas-Arteaga et al. (2009), Bhandari et al. (2015), Chen et al. (2021), Jiang et al. (2018) or Xu and Wang (2015). Thus, in this work, a linear elastic fracture mechanics concept is used to assess behavior of a short fatigue crack propagating from the corrosion pit surface, fatigue crack behavior near a corrosion pit was discussed in Malíková et al. (2022a,b). A rectangular specimen with a corrosion pit at its surface is modelled via finite element method and propagation of an angled crack under remote tensile cyclic loading is investigated by means of selected fracture criterion. Various corrosion pit geometries and initial crack inclination angles and lengths are considered, and the crack deflection angles are estimated. Geometry of the specimen under the study The research presented within this paper was performed numerically on a model reproducing the real specimen used to fatigue tests. Both the dimensions of the specimen suggested for the experimental campaign and geometrical and material properties of the numerical model are introduced within following sections. 1.1. Specimen geometry Three sets of cylindrical specimens were produced from high-strength steels S460, S690 and S960 in order to study their fatigue behavior under various level of corrosion, see an example in Fig. 1a. According to real samples, the dimensions of the specimen for numerical simulations were suggested, see. Fig. 2a. A scheme of the finite element model of a rectangular specimen which should simplify the real cylindrical specimen and represents the longitudinal cross-section in the middle of the specimen is then presented in Fig. 2c.

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Fig. 1. (a) Real cylindrical specimen prepared for fatigue tests; (b) drawing of the real specimen; (c) scheme of the numerical model of the corroded specimen with an angled fatigue crack subjected to remote tensile cyclic loading.

1.2. Numerical model and material properties

The dimensions of the rectangular specimen, circular-segment-shaped corrosion pit and fatigue crack considered within the finite element model were as follows: