Finite element analysis of shock-induced hull cavitation

Felippa, Carlos A.; DeRuntz, J. A.

doi:10.1121/1.2022844

Cited by 14 publications

(58 citation statements)

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“…Hughes 1987). In order to perform the coupling between solid and fluid regions in the domain decomposition approach, the scheme is implemented in a staggered predictor-multicorrector format, following the ideas of Park & Felippa (1980) and Felippa & Deruntz (1984). In addition, in Paper I the memory variable equations used to mimic attenuation with a constant quality factor Q were marched separately using a modified second-order Runge-Kutta scheme.…”

Section: Discretization and Time Marchingmentioning

confidence: 99%

Spectral-element simulations of global seismic wave propagation-II. Three-dimensional models, oceans, rotation and self-gravitation

Komatitsch¹,

Tromp²

2002

Geophysical Journal International

492

295

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Summary We simulate global seismic wave propagation based upon a spectral‐element method. We include the full complexity of 3‐D Earth models, i.e. lateral variations in compressional‐wave velocity, shear‐wave velocity and density, a 3‐D crustal model, ellipticity, as well as topography and bathymetry. We also include the effects of the oceans, rotation and self‐gravitation in the context of the Cowling approximation. For the oceans we introduce a formulation based upon an equivalent load in which the oceans do not need to be meshed explicitly. Some of these effects, which are often considered negligible in global seismology, can in fact play a significant role for certain source–receiver configurations. Anisotropy and attenuation, which were introduced and validated in a previous paper, are also incorporated in this study. The complex phenomena that are taken into account are introduced in such a way that we preserve the main advantages of the spectral‐element method, which are an exactly diagonal mass matrix and very high computational efficiency on parallel computers. For self‐gravitation and the oceans we benchmark spectral‐element synthetic seismograms against normal‐mode synthetics for the spherically symmetric reference model PREM. The two methods are in excellent agreement for all body‐ and surface‐wave arrivals with periods greater than about 20 s in the case of self‐gravitation and 25 s in the case of the oceans. At long periods the effect of gravity on multiorbit surface waves up to R4 is correctly reproduced. We subsequently present results of simulations for two real earthquakes in fully 3‐D Earth models for which the fit to the data is significantly improved compared with classical normal‐mode calculations based upon PREM. For example, we show that for trans‐Pacific paths the Rayleigh wave can arrive more than a minute earlier than in PREM, and that the Love wave is much shorter in duration.

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Section: Discretization and Time Marchingmentioning

confidence: 99%

Spectral-element simulations of global seismic wave propagation-II. Three-dimensional models, oceans, rotation and self-gravitation

Komatitsch¹,

Tromp²

2002

Geophysical Journal International

492

295

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show abstract

“…When the underwater explosion is sufficiently removed from the structure, the motion of the fluid surrounding the structure is small, which allows the fluid to be treated as acoustic but subject to cavitation. In 1984, Felippa and DeRuntz [7] developed a cavitating acoustic finite-element (CAFE) for FSI calculations based on the work of Newton [8][9][10][11], in which the wave field in the fluid is represented by a scalar displacement potential. Trilinear, isoparametric, eight-node brick elements were formulated; a six-node wedge element was added later [12].…”

Section: Cavitating Acoustic Finite-elements (Cafe)mentioning

confidence: 99%

“…The CAFE solution strategy for a ship-shock simulation consists of four steps ( Figure 2): (i) construct a finite-element (FE) model of the structure, (ii) interface it with a CAFE model of the fluid region in which cavitation is expected to occur, (iii) enclose the CAFE mesh with a non-reflecting boundary and (iv) start integrating the CAFE equations just before the incident wavefront reaches either the free surface of the fluid or the wet surface of the structure [7,14].…”

Section: Cavitating Acoustic Finite-elements (Cafe)mentioning

confidence: 99%

“…CAFEs were first implemented in the cavitating fluid analysis (CFA) code [7], with the structure equations being handled by the structural analysis of general shells (STAGS) [15] Nonreflecting Boundary finite-element program. The fluid mesh was bounded by a first-order doubly asymptotic approximation (DAA) [16,17], as implemented in the underwater shock analysis (USA) code [18].…”

Section: Cavitating Acoustic Finite-elements (Cafe)mentioning

confidence: 99%

“…Although the approach of Felippa and DeRuntz [7] is well developed, it has deficiencies that make it too expensive for accurate 3D simulations. First, CAFEs exhibit high numerical dispersion due to their use of low-order basis functions [25]; high mesh refinement is typically required.…”

Section: Deficiencies Of the Cafe Approachmentioning

confidence: 99%

See 2 more Smart Citations

A spectral‐element method for modelling cavitation in transient fluid–structure interaction

Sprague¹,

Geers²

2004

Numerical Meth Engineering

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Multiphase modeling of dynamic fluid–structure interaction during close‐in explosion

Xie

Young

Liu

2007

Numerical Meth Engineering

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SUMMARYThe modified ghost fluid method (MGFM) developed by Liu et al. (J. Comput. Phys. 2003; 190:651-681) provides us a robust method to treat moving compressible gas-gas and gas-liquid interfaces. Recently, the MGFM was extended to treat compressible fluid-compressible structure interfaces, where the structure was assumed to be very thick or infinitely thick (Comput. Mech. 2007; 40:667-681). In this work, the MGFM is applied to investigate the complex physics that occur during an underwater explosion inside a fluid-filled cylinder. Owing to the refraction of strong rarefaction waves at the fluid-structure interface and inside the thin cylinder wall, cavitation occurs next to the cylinder wall in the fluid; simultaneously, solid tension waves may appear next to the fluid-structure interface inside the structure. Both phenomena tend to cause the implicit double-shock approximate Riemann problem solver (the key component used to predict the fluid-structure interface status in the MGFM) to work less effectively in regions of low pressure and to be invalid when tension waves appear in the vicinity of the fluid-structure interface. To overcome these mentioned difficulties, the MGFM will be further developed in this work. Owing to the high initial pressure, short duration and high intensity of the shock load and cavitation reload, the compressibility of the structure becomes important, and the cylinder can be modeled as a compressible fluid-like medium. The hydro-elasto-plastic equation of state is, thus, used to describe the constitutive behavior of the compressible solid cylinder. A systematic study of the cavitation reload is conducted to examine the influence of the wall material, wall thickness, explosion distance, and explosion strength on the fluid and structural responses.

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Finite element analysis of shock-induced hull cavitation

Cited by 14 publications

References 0 publications

Spectral-element simulations of global seismic wave propagation-II. Three-dimensional models, oceans, rotation and self-gravitation

Spectral-element simulations of global seismic wave propagation-II. Three-dimensional models, oceans, rotation and self-gravitation

A spectral‐element method for modelling cavitation in transient fluid–structure interaction

Multiphase modeling of dynamic fluid–structure interaction during close‐in explosion

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