A meshless Smoothed Particle Hydrodynamics solid solver is developed in order to study fluidstruc... more A meshless Smoothed Particle Hydrodynamics solid solver is developed in order to study fluidstructure interactions and to predict cavitation erosion. The solid solver is developed in-house in an axisymmetric configuration. The existing SPH methods dedicated to solid materials do not allow a consistent treatment of particles close to the symmetry axis, so a density correction scheme is proposed here to derive new density and momentum equations for solid mechanics in axisymmetric SPH formulation. The new SPH equations are coded in the solver and the SPH solid solver is then validated against FEM results which shows excellent agreement.
Journal of the Mechanics and Physics of Solids, 2019
A meshless Smoothed Particle Hydrodynamics solver is used to simulate the collapse of a cavitatio... more A meshless Smoothed Particle Hydrodynamics solver is used to simulate the collapse of a cavitation bubble near a solid material taking into account the complex fluid-structure interaction. A parametric study has been performed to study the effect of stand-off ratio, bubble size, driving pressure and strain rate on the material response. We focus on plastic strain magnitudes and plastic strain energy dissipation to compare different cases and their ability to cause material erosion. Findings indicate that, in the case of repeated collapses, cavities attached to the solid have an ability to initiate damage quicker but exhibit lower erosion rate compared to the cavities detached from the solid. The incubation time does not depend on the size of the bubbles, unlike the erosion rate which is strongly affected by the bubble size. It is also found that the amount of cumulated plasticity is overestimated by more than 150% when the strain-rate sensitivity is not taken into account in the material modelling which suggests that using an appropriate plasticity model that includes strain-rate sensitivity is mandatory while studying the phenomenon of cavitation erosion.
Journal of the Mechanics and Physics of Solids, 2018
A Smoothed Particle Hydrodynamics axisymmetric solver was developed in order to simulate the coll... more A Smoothed Particle Hydrodynamics axisymmetric solver was developed in order to simulate the collapse of a single cavitation bubble close to an elastic-plastic material and study plasticity formation and hence material erosion. Findings indicate the relative importance of the material deformation due to the impact of the micro-jet and the shock wave that develop during collapse. A shock-wave dominated impact has a much higher material erosion ability compared to a micro-jet impact. Strain rate is found to have a significant effect on plastic deformation, with an overestimation of the plastic deformation up to 60% if strain rate effects are neglected in the case of stainless steel A2205. We also demonstrate that, although the impact pressure is maximum just below the collapsing bubble, maximum plastic strain occurs at a radial offset from the symmetry axis. This is the result of inertial effects that have an impact on both the magnitude and the position of the plastic domain in the material. A new non-dimensional parameter called effective pressure is introduced that can predict plastic strain location accurately for higher stand-off ratios. Alternatively, a characteristic time analysis also shows that it can be used for prediction of plastic strain zone in the solid for detached cavities.
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Papers by Shrey Joshi