Notes on Constitutive Relations for Porous Solids

2020 ◽  
pp. 61-85
Author(s):  
Pasquale Giovine
Keyword(s):  
Constitutive Relations ◽  
Porous Solids

AN ELASTOPLASTIC CONSTITUTIVE MODEL FOR POROUS MATERIALS

2013 ◽  
Vol 05 (03) ◽  
pp. 1350035 ◽  
Author(s):  
ZHUPING HUANG ◽  
YONGQIANG CHEN ◽  
SHU-LIN BAI
Keyword(s):  
Mechanical Properties ◽  
Constitutive Model ◽  
Porous Materials ◽  
Constitutive Relations ◽  
Matrix Material ◽  
Three Dimensional ◽  
Porous Solids ◽  
Additional Material ◽  
Prediction Of Mechanical Properties ◽  
Elastoplastic Constitutive Model

A micromechanics-based elastoplastic constitutive model for porous materials is proposed. With an assumption of modified three-dimensional Ramberg–Osgood equation for the compressible matrix material, the variational principle based on a linear comparison composite is applied to study the effective mechanical properties of the porous materials. Analytical expressions of elastoplastic constitutive relations are derived by means of micromechanics principles and homogenization procedures. It is demonstrated that the derived expressions do not involve any additional material constants to be fitted with experimental data. The model can be useful in the prediction of mechanical properties of elastoplastic porous solids.

A Study on the Constitutive Law for Porous Solids With Pressure-Sensitive Matrices and on the Material Behavior of Rubber-Toughened Epoxies

1999 ◽  
Author(s):  
Hyun-Yong Jeong
Keyword(s):  
Finite Element ◽  
Void Nucleation ◽  
Yield Criterion ◽  
Constitutive Relations ◽  
Numerical Results ◽  
Material Behavior ◽  
Porous Solids ◽  
Normal Stresses ◽  
Pressure Sensitive ◽  
Rubber Toughened

Abstract A macroscopic yield criterion for porous solids with pressure-sensitive matrices modeled by Coulomb’s yield criterion was obtained by generalizing Gurson’s yield criterion with consideration of the hydrostatic yield stresses for a spherical thick-walled shell and by fitting the finite element results of a voided cube. The macroscopic yield criterion is valid for negative mean normal stresses as well as for positive mean normal stresses. From the yield criterion, a plastic potential function for the porous solids was derived either for plastic normality flow or for plastic non-normality flow of pressure-sensitive matrices. In addition, elastic relations, an evolution rule for the plastic behavior of the matrices, a consistency equation and a void volume evolution equation were presented to complete a set of constitutive relations. The set of constitutive relations was implemented into a finite element code ABAQUS to analyze the material behavior of rubber-toughened epoxies. The cavitation and the deformation behavior were analyzed around a crack tip under three-point bending and around notch tips under four-point bending. In the numerical analyses, the cavitation of rubber particles was considered via a stress-controlled void nucleation model. The numerical results indicate that a reasonable cavitation zone can be obtained with void nucleation being controlled by the macroscopic mean normal stress, and a plastic zone is smaller around a notch tip under compression than under tension. These numerical results agree well with corresponding experimental results on the cavitation and plastic zones.

Controlling Gas Selectivity in Molecular Porous Liquids by Tuning the Cage Window Size

2019 ◽  
Author(s):  
Benjamin Egleston ◽  
Konstantin V. Luzyanin ◽  
Michael C. Brand ◽  
Rob Clowes ◽  
Michael E. Briggs ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Chemical Synthesis ◽  
Field Gradient ◽  
Window Size ◽  
Standard Approach ◽  
Porous Solids ◽  
Pulsed Field Gradient Nmr ◽  
Pulsed Field ◽  
Cage Molecules ◽  
Gas Selectivity

Control of pore window size is the standard approach for tuning gas selectivity in porous solids. Here, we present the first example where this is translated into a molecular porous liquid formed from organic cage molecules. Reduction of the cage window size by chemical synthesis switches the selectivity from Xe-selective to CH<sub>4</sub>-selective, which is understood using <sup>129</sup>Xe, <sup>1</sup>H, and pulsed-field gradient NMR spectroscopy.

Controlling Gas Selectivity in Molecular Porous Liquids by Tuning the Cage Window Size

2019 ◽  
Author(s):  
Benjamin Egleston ◽  
Konstantin V. Luzyanin ◽  
Michael C. Brand ◽  
Rob Clowes ◽  
Michael E. Briggs ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Chemical Synthesis ◽  
Field Gradient ◽  
Window Size ◽  
Standard Approach ◽  
Porous Solids ◽  
Pulsed Field Gradient Nmr ◽  
Pulsed Field ◽  
Cage Molecules ◽  
Gas Selectivity

Control of pore window size is the standard approach for tuning gas selectivity in porous solids. Here, we present the first example where this is translated into a molecular porous liquid formed from organic cage molecules. Reduction of the cage window size by chemical synthesis switches the selectivity from Xe-selective to CH<sub>4</sub>-selective, which is understood using <sup>129</sup>Xe, <sup>1</sup>H, and pulsed-field gradient NMR spectroscopy.

Two Consecutive Magneto-Structural Gas-Solid Transformations with Single-Crystal Retention in Non-Porous Molecular Materials

2018 ◽  
Author(s):  
Julia Miguel-Donet ◽  
Javier López-Cabrelles ◽  
Nestor Calvo Galve ◽  
Eugenio Coronado ◽  
Guillermo Minguez Espallargas
Keyword(s):  
Solid State ◽  
Single Crystal ◽  
Structural Rearrangement ◽  
Magnetic Behaviour ◽  
Porous Solids ◽  
Potential Applications ◽  
Hcl Gas ◽  
Porous Coordination Polymer ◽  
Gas Molecules ◽  
Magnetostructural Transformation

<p>Modification of the magnetic properties in a solid-state material upon external stimulus has attracted much attention in the recent years for their potential applications as switches and sensors. Within the field of coordination polymers, gas sorption studies typically focus on porous solids, with the gas molecules accommodating in the channels. Here we present a 1D non-porous coordination polymer capable of incorporating HCl gas molecules, which not only causes a reordering of its atoms in the solid state but also provokes dramatic changes in the magnetic behaviour. Subsequently, a further solid-gas transformation can occur with the extrusion of HCl gas molecules causing a second structural rearrangement which is also accompanied by modification in the magnetic path between the metal centres. Unequivocal evidence of the two-step magnetostructural transformation is provided by X-ray single-crystal diffraction.</p>

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