PSI - Issue 18

Fokion Oikonomidis et al. / Procedia Structural Integrity 18 (2019) 142–162 Dr Fokion Oikonomidis/ Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 4. Details of the notch geometry at the centre of the leg (left, unloaded; right, loaded).

The plastic behaviour was defined in terms of true stress and strain because of the large deformations taking place during proof loading. This behaviour was associated with a non-linear geometry option updating the shape of the elements with the strains calculated. The stress – strain curve is shown in Fig. 5. A contact condition was defined between the chain links for the proof loading analysis, with a friction coefficient equal to 0.2. The proof load, acting in the direction of the chain axis, was applied to the reference point linked to the nodes lying on the cross section of one link. The tensile load was then relieved, the contact between the links was removed and a bending load for pre cracking was applied at the extrados, through a roller 50mm in radius.

Fig. 5. True stress – true strain curves used for modelling the plastic behaviour of R5 Grade.