PSI - Issue 60

Dhanesh N. et al. / Procedia Structural Integrity 60 (2024) 456–470 Dhanesh et al. / StructuralIntegrity Procedia 00 (2019) 000 – 000

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Fig. 3. 3D profile of the dent

3.2. Finite Element Model

The simulation of the pipeline dent is carried out in the commercial finite element (FE) package ABAQUS/CAE 2019. For simulating the actual site condition, the FE model includes the native soil, embankment (old and expended stretch of the road), trench, casing, etc., along with the dented pipeline. Fig.4 shows the 3D view of the complete FEA model with different features.

Fig. 4. 3D view of FEA model

The native soil and embankments are modelled and meshed using 8-node linear hexahedral continuum elements with reduced integration (C3D8R). In the FE model, the embankment is simulated in two stages. In the first stage (Stage-1), the initially constructed 22 m wide embankment is modelled along with the native soil. In this stage, the pipeline located outside the casing is assumed to be installed by the trenching method. Hence the trench is modelled appropriately. The trench is also assumed to be constructed in layers, and it is simulated by sequential activation of soil layers (five layers). Fig.5 shows the view of the trench along with the old embankment. In the second stage (Stage -2), the newly constructed portion of the embankment is activated.

Fig. 5. Geometry of trench and layer-wise filling (Stage-1)