Blast loading with high pressure intensity propagates within a fraction of second after an explosion. Depending on the amount of energy and wave velocity released, blast loading is highly likely to cause substantial structural damage and leads to a total failure. Taking into account various interests and requirements in the protective structures, the investigation of damage behaviour and structural responses due to this extreme condition is therefore vital. The prime objective of this research is to develop an established framework of numerical modelling of reinforced concrete slabs and protective structures subjected to blast loading. Subsequently investigate the damage mechanisms, dynamic responses and post-failures. The scabbing, spalling, crater and shear plug are of particular interest, with special attention paid to the progressive fracture and its associated velocity. Three major modelling aspects were given the most attention in term of blast loading, material model and fracture modelling. The interaction between non-uniform blast loading and reinforced concrete slabs was modelled using the combined finite-discrete element method. The finite element method was incorporated with a rotating crack approach and discrete element to model the fracture onset and the dynamic post-failures. In the numerical modelling, a mapping method was employed to define blast pressure due to incompatibility of the Jones-Wilkins-Lee method with all compressible material models. The blast loading was determined based on cumulative loads of the incident overpressure, the reflected overpressure and the dynamic wind blast. The calculated blast loading was compared with that obtained from the US Army standard, TMS-1300/UFC-03-340. The Mohr-Coulomb and Von-Mises criteria were applied for the concrete and steel reinforcement respectively. Since the Mohr-Coulomb criterion in concrete can only produce continuum failure, the Rankine with fracture model was introduced to control tensile fracture failure. Meanwhile, a multi-scale simulation was applied to overcome the lack of constitutive material model for the ceramic composite layer. The multi-scale simulation is based on the linear boundary condition, employing a unit cell of ceramic composite with uniaxiallbiaxial loading and a nonlinear anisotropic brittle model. The comparison between numerical and experimental results shows a favourable agreement and gives a reliable prediction on the damage behaviour and structural responses. The fracture and post-failures. however, are still ambiguous and need for further investigation.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:643433 |
| Date | January 2013 |
| Creators | Bin Mohd Jaini, Zainorizuan |
| Publisher | Swansea University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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