Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/31651
Title: Response and failure mechanisms of structural member under high velocity impact
Authors: MD. JAHIDUL ISLAM
Keywords: Finite element method (FEM), smooth particle hydrodynamics (SPH), high velocity impact, strain rate effect, adiabatic heating, material modeling
Issue Date: 19-Aug-2011
Source: MD. JAHIDUL ISLAM (2011-08-19). Response and failure mechanisms of structural member under high velocity impact. ScholarBank@NUS Repository.
Abstract: For numerical study of structural responses under high velocity impact (HVI), it is essential to adopt an effective discretization method and a robust material model. Numerical studies involving the finite element method (FEM) suffers from severe element distortion problem when subjected to HVI, which can be either resolved by adopting the element erosion approach in the FEM or by implementing the coupled smooth particle hydrodynamics (SPH) - FEM (SFM) where the SPH is employed only in severely distorted regions and the FEM otherwise. Two new material models with emphasis on strain rate effect are proposed for metallic plates and concrete slabs. Both models are implemented as a used defined material model in the LS-DYNA and verified against several HVI problems. The numerical simulations using the proposed models show a good agreement with the experimental observations, especially, on the residual velocities, penetration depths and failure patterns of the target plates. The SFM is able to emulate the failure mechanisms of the metallic target plates for initial impact velocity of 170 m/s and higher. For lower impact velocities and relatively thin plates, the FEM with element erosion show better correlation with the experimental observations. Since no direct method exist to determine the failure criteria in element erosion approach, a calibration method is proposed to establish suitable failure strain values for concrete slabs.
URI: http://scholarbank.nus.edu.sg/handle/10635/31651
Appears in Collections:Ph.D Theses (Open)

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