Suggested Modification of the <i>P</i>-α Model for Porous Materials

Carroll, M. M.; Holt, Albert C.

doi:10.1063/1.1661203

Cited by 126 publications

(52 citation statements)

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“…For the low stress regime, the Wu-Jing model implements the Carrol-Holt form of the P − α model [5]. In the present study, the P − α model was modified according to the method outlined in [3], in which a configuration parameter, n, was introduced to take into account the surfacearea of the various powders.…”

Section: Experiments Detailmentioning

confidence: 99%

The influence of particle morphology on the dynamic densification of metal powders

Eakins

Chapman

2012

AIP Conference Proceedings

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Abstract. Powders are well known for their dispersive properties, which derive from the many dissipative processes that occur during densification. While numerous studies have been devoted to understand these processes over a wide range of initial densities, the influence of particle morphology has been for the large part overlooked. In this paper, we discuss a new research campaign at the Institute of Shock Physics, to systematically investigate the role of starting configuration on the dynamic densification of metal powders. Multi-target gun loading experiments have been performed on both stainless steel and copper powders of equiaxed-and fiber-shaped morphology. Frequency-shifted PDV was employed to measure the structure and velocity of the dynamic densification wave, to yield the crush strength of the various powders. We find that while the crush strength for the stainless steel powders is reasonably described by a modified Wu-Jing model, this model underpredicts the densification stress for the copper powder.

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Section: Experiments Detailmentioning

confidence: 99%

The influence of particle morphology on the dynamic densification of metal powders

Eakins

Chapman

2012

AIP Conference Proceedings

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“…Our porosity model is based on the P − alpha model originally proposed by Herrmann (1969) and later modified by Carroll and Holt (1972). The model provides a description of microscopic porosity with pore-sizes beneath the spatial resolution of our numerical scheme (sub-resolution porosity) and which is homogeneous and isotropic.…”

Section: Porosity Modelmentioning

confidence: 99%

“…The factor 1/α in Eq. (3) was introduced by Carroll and Holt (1972) to take into account that the volume average of the stress in the matrix is given by…”

Section: P − Alpha Modelmentioning

confidence: 99%

“…In the original work of Herrmann (1969) and Carroll and Holt (1972), the P − alpha model was intended to be a first order theory in which shear strength effects are considered secondary and consequently, the stress tensor was assumed to be diagonal. In this work, we use the full stress tensor and therefore, we extend the original model with a relation between the distention and the deviatoric stress tensor (Sec.…”

Section: Our Actual Modelmentioning

confidence: 99%

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Numerical simulations of impacts involving porous bodies

Jutzi

Benz

Michel

2008

Icarus

129

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In this paper, we extend our Smooth Particle Hydrodynamics (SPH) impact code to include the effect of porosity at a sub-resolution scale by adapting the so-called P − alpha model. Many small bodies in the different populations of asteroids and comets are believed to contain a high degree of porosity and the determination of both their collisional evolution and the outcome of their disruption requires that the effect of porosity is taken into account in the computation of those processes. Here, we present our model and show how porosity interfaces with the elastic-perfectly plastic material description and the brittle fracture model generally used to simulate the fragmentation of non-porous rocky bodies. We investigate various compaction models and discuss their suitability to simulate the compaction of (highly) porous material. Then, we perform simple test cases where we compare results of the simulations to the theoretical solutions. We also present a Deep Impact-like simulation to show the effect of porosity on the outcome of an impact. Detailed validation tests will be presented in a next paper by comparison with high-velocity laboratory experiments on porous materials (Jutzi et al., in preparation). Once validated at small scales, our new impact code can then be used at larger scales to study impacts and collisions involving brittle solids including porosity, such as the parent bodies of C-type asteroid families or cometary materials, both in the strength-and in the gravity-dominated regime.

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“…Carroll and Holt [4]. In our model, we prescribed a Hugoniot elastic limit of 5 0 MPa, with complete pore crushup occurring at 161 MPa.…”

Section: 0 Liner Characterizationmentioning

confidence: 99%

Pressure-Enhanced Penetration with Shaped-Charge Perforators

Glenn¹

1998

All Days

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Suggested Modification of the P-α Model for Porous Materials

Abstract: We suggest that the relationship between the pressure P in a porous material and the average matrix pressure Pm in the material should be P=Pm/α, where α is the ratio of the specific volumes of the porous material and the matrix material.

Cited by 126 publications

References 1 publication

The influence of particle morphology on the dynamic densification of metal powders

The influence of particle morphology on the dynamic densification of metal powders

Numerical simulations of impacts involving porous bodies

Pressure-Enhanced Penetration with Shaped-Charge Perforators

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