Dynamic response of deformable structures subjected to shock load and cavitation reload

Abstract

The dynamic response of deformable structures subjected to shock load and cavitation reload has been simulated using a multiphase model, which consists of an interface capturing method and a one-fluid cavitation model. Fluid-structure interaction (FSI) is captured via a modified ghost fluid method (Liu et al. in J Comput Phys 190:651-681, 2003), where the structure is assumed to be a hydro-elasto-plastic material if subjected to a strong shock load. Bulk cavitation near the structural surface is captured using an isentropic model (Liu et al. in J Comput Phys 201:80-108, 2004). The integrated multiphase model is validated by comparing numerical predictions with 1D analytical solutions, and with numerical solutions calculated using the cavitation acoustic finite element (CAFÉ) method (Sprague and Geers in Shocks vib 7: [105][106][107][108][109][110][111][112][113][114][115][116][117][118][119][120][121][122] 2001). To assess the ability of the multiphase model for multi-dimensions, underwater explosions (UNDEX) near structures are computed. The importance of cavitation reloading and FSI is investigated. Comparisons of the predicted pressure time histories with different explosion center are shown, and the effect on the structure is discussed.

Two-dimensional shock induced collapse of gas bubble near a semiinfinite deformable solid

“…Due to strong shock wave propagation and high density ratios between the fluid mediums, the numerical method should be high-order (at least second), high resolution, and robust. The present numerical method, called the multiphase compressible hydrodynamic model (MCHM), comprises a second-order Monotone Upstream-centered Scheme for Conservation Laws (MUSCL)-developed by Van Leer [1974] for calculating the fluid variables of the region away from the interfaces-and an explicit characteristic method [Xie et al 2007b] for calculating the variables (pressure, velocity and entropy) at the interfaces.…”

“…Therefore, an efficient and robust interface treatment technique is necessary. The multiphase compressible hydrodynamic model (MCHM) employs an explicit characteristic method to calculate interface variables (pressure, velocity and entropy), which is simplified from the modified ghost fluid method (MGFM by Liu et al [2003]) and has been validated with one-dimensional analytical solutions in [Xie et al 2007b]. Formulation of the explicit characteristic method for twodimensional problems starts from the characteristic equations for Equation (2-1) in the normal direction of the material interface:…”

“…It should be noted that Kambouchev et al [2006] focused on the dynamic response of the rigid plates and assumed that the plate deformation and stresswave propagation through the plate are negligible. This assumption is valid for stiff materials like steel or copper but may not be for softer ones like aluminum and plastic, where significant energy dissipates through the fluid-solid interface and the stress-wave propagation becomes important [Xie et al 2007b;Xie et al 2006].…”

“…Due to the strong short-duration pressure loads, the solid can be simulated as a compressible fluid medium governed by the hydro-elasto-plastic equation of state [Tang and Sotiropoulos 1999;Xie et al 2006]. Therefore, the system can be treated as a gas-water-solid three-phase compressible system and can thus be solved using a multiphase compressible hydrodynamic solver [Xie et al 2007b;Xie et al 2006]. The objective of this paper is to investigate the effect of shock-induced bubble collapse on a nearby semiinfinite solid and the countereffect of solid deformation on the fluid and bubble dynamics and on the shock wave propagation.…”

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“…It should be noted that focused on the dynamic response of the rigid plates and assumed that the plate deformation and stresswave propagation through the plate are negligible. This assumption is valid for stiff materials like steel or copper but may not be for softer ones like aluminum and plastic, where significant energy dissipates through the fluid-solid interface and the stress-wave propagation becomes important [Xie et al 2007b;Xie et al 2006].…”