LIMIT STRENGTH OF NEW SANDWICH PIPES WITH STRAIN HARDENING CEMENTITIOUS COMPOSITES (SHCC) CORE: FINITE ELEMENT MODELLING

摘要

Sandwich Pipes (SP) can be an effective solution for the ultra-deepwater submarine pipeline, combining high structural resistance with thermal insulation. Besides polymer, strain hardening cementitious composites (SHCC), a micromechanically designed material with the characteristic of high tensile ductility, can be another choice for the annular material. The purpose of this work is to investigate numerically the limit strength of SP with SHCC under external pressure and longitudinal bending. The mechanical behaviour of SHCC is simulated using a Concrete Damaged Plasticity (CDP) model provided by Abaqus/Standard. The finite element (FE) model is employed to better understand the structural behaviour of SP in different conditions of geometry, adhesion and loading. The pressure-curvature (P — K) failure envelopes for SP with unbonded and fully bonded interface conditions are presented. The results show that the resistance of the annulus layer has a great contribution for the overall structural behaviour. The interface condition and the thickness of the annulus are important influence factors on the overall structural behaviour. Besides, the lateral confinement effect on SHCC caused by the inner and outer steel tubes and the ultra high ductility of the SHCC have strong influence on the results for the pressure-curvature collapse envelopes.