Identification and Determination of Material Properties for Porohyperelastic Analysis of Large Arteries

1998 ◽  
Vol 120 (2) ◽  
pp. 188-194 ◽  
Author(s):  
B. R. Simon ◽  
M. V. Kaufmann ◽  
M. A. McAfee ◽  
A. L. Baldwin ◽  
L. M. Wilson
Keyword(s):  
Experimental Data ◽  
Data Reduction ◽  
Material Properties ◽  
Effective Strain ◽  
Material Model ◽  
Radial Component ◽  
Constitutive Law ◽  
Hydraulic Permeability

A “porohyperelastic” (PHE) material model is described and the theoretical frame-work presented that allows identification of the necessary material properties functions for soft arterial tissues. A generalized Fung form is proposed for the PHE constitutive law in which the two fundamental Lagrangian material properties are the effective strain energy density function, We, and the hydraulic permeability, k˜ij. The PHE model is based on isotropic forms using We=Ue(φ)=1/2C0(eφ−1) and the radial component of permeability, k˜RR=k˜RR(φ), with φ=C′1(I¯1−3)+C′2(I¯2−3)+K′(J−1)2. The methods for determination of these material properties are illustrated using experimental data from in situ rabbit aortas. Three experiments are described to determine parameters in Ue and k˜RR for the intima and media of the aortas, i.e., (1) undrained tests to determine C0, C′1, and C′2 (2) drained tests to determine K′; and (3) steady-state pressurization tests of intact and de-endothelialized vessels to determine intimal and medial permeability (adventitia removed in these models). Data-reduction procedures are presented that allow determination of k˜RR for the intima and media and Ue for the media using experimental data. The effectiveness and accuracy of these procedures are studied using input “data” from finite element models generated with the ABAQUS program. The isotropic theory and data-reduction methods give good approximations for the PHE properties of in situ aortas. These methods can be extended to include arterial tissue remodeling and anisotropic behavior when appropriate experimental data are available.

Prediction of Mechanical Properties of Al-Based FGM Crash Box Fabricated by Heat Treatment Process

2013 ◽  
Vol 465-466 ◽  
pp. 647-651 ◽  
Author(s):  
Saifulnizan Jamian ◽  
Mohammad Rusydi Zainal Abidin
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Heat Treatment ◽  
Temperature Distribution ◽  
Material Properties ◽  
Interpolation Method ◽  
Functionally Graded ◽  
Local Material ◽  
Local Material Properties

In this paper, mechanical properties of Al functionally graded materials (FGMs) crash box fabricated by heat treatment is predicted based on temperature distribution and experimental data. The Al FGM crash box is fabricated by applying different temperature at the both ends of a square hollow Al column for 4 hours. Due to the gradient in heat treatment temperature along the height of the Al column, the microstructure is locally varied so that a certain variation of local material properties is achieved. The determination of material properties at any point along the height of Al FGM crash box experimentally is uneasy. The Lagrange interpolation method is proposed to predict the variation of local material properties at any point along the height of Al FGM crash box for further work such as simulation of impact on the crash box. The determination of mechanical properties is successfully predicted using the available experimental data and the temperature distribution obtained in simulation.

Solid State Property - Bonding Electron Density – Volume Plasmon Energy Scaling Relationships: Novel AEM Technique for In Situ Diagnostics of Material Properties at the Nanoscale

2003 ◽  
Vol 791 ◽  
Author(s):  
Vladimir P. Oleshko ◽  
James M. Howe
Keyword(s):  
Solid State ◽  
Electron Density ◽  
Material Properties ◽  
Structure Property ◽  
Local Material ◽  
State Densities ◽  
Local Material Properties ◽  
Bonding Electron

ABSTRACTQuantized high-frequency (∼1016 Hz) correlated longitudinal electron excitations (plasmons) generated in the energy-loss range 0–50 eV by fast electrons passing through any solid enable one to probe various states of matter. Their energy, Ep, is directly related to the density of valence electrons, thus allowing determination of solid-state properties that are governed by ground-state densities. Universal features and scaling in relations between Ep and the cohesive energy per atomic volume, bonding electron density and elastic constants have been established. The resulting correlations follow the universal binding energy relationship, thus providing new insights into the fundamental nature of structure-property relationships. They allow direct in situ determination of local material properties in an analytical electron microscope, as illustrated by examples utilizing Al- and Ti-based structural alloys.

The measurement of the hydraulic permeability of saturated soil in situ . II

1953 ◽  
Vol 216 (1124) ◽  
pp. 72-89 ◽  
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Potential Distribution ◽  
Hydraulic Permeability ◽  
Two Dimensional ◽  
Capillary Fringe ◽  
Isotropic Media ◽  
Two Dimensional Flow

After a brief description of a new sand-tank laboratory and equipment for studying problems of the flow of fluids in porous materials, the remainder of the paper is devoted to an account of the application of a part of this equipment to a study of the flow of water between a pair of wells, such as is required for the determination of the permeability of the sand by the method described in part I. The potential distribution about the wells is found to conform sufficiently well with theory to justify the application of the analysis of part I, the interference due to the confining walls being satisfactorily negligible. The perturbation of the water table inseparable from the imposition of a potential difference between the wells is found not to invalidate the results based on an assumption of two-dimensional flow, while the corrections on account of the presence of a capillary fringe and a surface of seepage are satisfactorily made by adding to the measured depth of water in the well an increment equal to about half the thickness of the capillary fringe. The end correction for non-penetrating wells is also sufficiently well made by an addition to the measured depth of water; the magnitude of the correction is given for isotropic media for a well system of the dimensions used here, and the method of applying it to anisotropic media is indicated. The two-well method is used to estimate the permeability of the sand, which is then discussed in relation to the pore-size distribution. The elucidation of the permeability profile in a succession of strata is then discussed. Finally, techniques suited to work in the field are described, and a few preliminary fields results are quoted.

Analysis Methodology of Inelastic Constitutive Parameter Using State Space Method and Neural Network

2018 ◽  
Vol 7 (3.34) ◽  
pp. 163
Author(s):  
JoonSeong Lee ◽  
. .
Keyword(s):  
Experimental Data ◽  
State Space ◽  
Inelastic Strain ◽  
Material Model ◽  
Constitutive Law ◽  
Training Data ◽  
Model Errors ◽  
Output Data ◽  
Proposed Model ◽  
Space Method

Background/Objectives: In this paper, we present a method for describing a set of variables of an inelastic constitutive equation based on state space method (SSM) and neural network (NN). The advantage of this method is that it can identify the appropriate parameters.Methods/Statistical analysis: Two NNs based on SSM are proposed. One outputs the ratio of inelastic strain for the internal parameters of the material, and the other is the following state of the inelastic strain ratio and material internal variable. Both NNs were trained and successfully collected using input and output data generated by Chaboche 's model.Findings: As a result, previous NNs have demonstrated their validity as a powerful material model. However, the training data for the proposed NN can’t be easily obtained from actual experimental data. Previous neural networks can reproduce the original stress-strain curves. The NNs also produced untrained curves to demonstrate interpolation capabilities. It was also found that the NNs can be estimated to be close to training data. The author defines the implicit constitutive model and proposes the implicit viscous constitutive model using NNs. In modeling, inelastic behavior is generalized in state space representation, and the state space form is constructed by NNs using an input-output data sets. The proposed model was first created from the pseudo-experimental data generated by one of the commonly used configuration models and has been found to be a good replacement for the model. The actual experimental data was then tested, and the proposed model showed the accuracy of its superiority over all existing specified models because the amount of model errors was negligible.Improvements/Applications: The comparison between the NN constitutive laws   with the Chaboche’s model indicates that the NN constitutive law generated curves with less model errors than the experimental data, thereby indicating the superiority of the neural constitutive law to explicit constitutive laws as a material model.  

scholarly journals A New Method for the Estimation of Hydraulic Permeability, Coefficient of Consolidation, and Soil Fraction Based on the Dilatometer Tests (DMT)

2019 ◽  
Vol 41 (4) ◽  
pp. 212-222 ◽  
Author(s):  
Simon Rabarijoely
Keyword(s):  
Permeability Coefficient ◽  
Clay Soil ◽  
Life Sciences ◽  
Hydraulic Permeability ◽  
Coefficient Of Consolidation ◽  
Soil Fraction ◽  
Overburden Stress ◽  
Flat Dilatometer Test

AbstractThe main issue of the paper is the estimation of soil hydraulic permeability based on the DMT test. DMTA, DMTC and SASK methods performed in the Nielisz dam, Stegny and the SGGW Campus of the Warsaw University of Life Sciences sites are described. The article presents the implementation of the dilatometer Marchetti test (DMT) in the determination of soil fraction and effects of its occurrence in the subsoil, tested in the Nielisz dam located in the Wieprz river valley in the Lublin province, and in various sites in Warsaw (Stegny site and SGGW Campus of the Warsaw University of Life Sciences). In order to acquire the needed data, the flat dilatometer test (DMT) method was used. A direct and indirect pressure methodology of interpreting soil swelling was characterized in the article. The paper shows the possibilities of determining sand, silt and clay soil fractions based on po and p1 pressures from dilatometer tests (DMT) and the effective (σ’vo) and total (σvo) vertical in situ overburden stress. Additionally, the main advantage of this paper is the proposal of use of a new chart to determine hydraulic permeability and soil fraction, based on DMT tests.

DETERMINING MATERIAL PROPERTIES OF NATURAL RUBBER USING FEWER MATERIAL MODULI IN VIRTUE OF A NOVEL CONSTITUTIVE APPROACH FOR ELASTIC BODIES

2018 ◽  
Vol 91 (2) ◽  
pp. 375-389 ◽  
Author(s):  
A. Muliana ◽  
K. R. Rajagopal ◽  
D. Tscharnuter ◽  
B. Schrittesser ◽  
G. Saccomandi
Keyword(s):  
Experimental Data ◽  
Natural Rubber ◽  
Material Properties ◽  
Biaxial Loading ◽  
Uniaxial Stretching ◽  
Insignificant Change ◽  
Elastic Bodies ◽  
In Virtue Of ◽  
Rubberlike Materials

ABSTRACT We discuss the development of a method for the determination of the material properties of rubber and rubberlike materials within the context of a novel constitutive framework that has been put into place recently. The new constitutive framework leads to fewer material moduli than the models that are currently in vogue. We corroborate the predictions of our model against the experimental data of Treloar as well as Jones and Treloar for uniaxial and biaxial loadings and also with regard to new experimental results that have been generated by us for uniaxial stretching of natural rubber. We record both the axial and lateral responses of the specimens. This allows us to also examine the compressibility of the natural rubber specimens. Finally, we also characterize the response of compressible elastic bodies both under the assumption that the motion is isochoric, as the experiments suggest insignificant change in volume, as well as without resorting to such an assumption, when subjected to biaxial loading.

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