PSI - Issue 39

Jesús Toribio et al. / Procedia Structural Integrity 39 (2022) 722–725 Author name / Procedia Structural Integrity 00 (2021) 000–000

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Fig. 2. Crack path just before fracture (left) and fractographic aspect of the vertical cracking path showing enlarged and oriented cleavage (right).

3. Numerical analysis A large-displacement elastoplastic finite element analysis was performed within updated Lagrangian formulation. The material properties were those associated with the cold drawn pearlitic steel analyzed in this paper. The cleavage stress to produce crack path deflection in axial (vertical) direction should be the horizontal stress in the crack direction, i.e., the σ xx component of the stress tensor, whose distributions for different loading levels ( σ c /100, σ c /10, σ c /2 and σ c , where σ c is the critical remote stress at fracture) are given in Fig. 3.

Fig. 3. Distributions of cleavage stress σ xx at increasing loading levels σ c /100, σ c /10, σ c /2 and σ c , where σ c is the remote stress at fracture.

The local maximum of the cleavage stress appears at a certain distance form the crack tip, and such a distance increases with the loading level, cf. Fig. 4. This σ xx stress is the responsible for crack path deflection, consistent with previous research (Toribio and Ayaso, 2020) on notched samples of cold drawn pearlitic steel showing the necessity of both stress triaxiality (constraint) and microstructural anisotropy (orientation) to produce fracture path deflection.