An Advanced Cap Model for Soil

2003 ◽  
Author(s):  
C. S. Tsai ◽  
Ching-Shyang Chen ◽  
Zhen-Yu Zhang ◽  
Bo-Jen Chen ◽  
J. C. Chen
Keyword(s):  
Failure Surface ◽  
Material Behavior ◽  
Constitutive Law ◽  
Octahedral Plane ◽  
Sensitive Material ◽  
Stress Strain ◽  
Stress Strain Relation ◽  
Highly Nonlinear ◽  
Cap Model ◽  
Strain Relationship

Soil, which is a pressure-sensitive material, is frequently encountered in the engineering profession. To ensure the safety of super-structures, it is prerequisite to fully understand the mechanical behavior of soil. The stress-strain relation of soil is highly nonlinear and complex. Therefore, problems involving soil need an appropriate constitutive model to describe its stress-strain relationship. This paper presents a new cap-type constitutive law for soil. The model is prominent in the sense that it satisfies the compatibility between the failure surface and the yield cap. It has modified the classical cap model to obtain smooth yield surfaces. In addition, the model effectively describes strength variations along various directions on the octahedral plane. The model has shown to realistically simulate soil responses in experiments by 7 parameters. The proposed concept can also be extended to include as many previous models published in the past for describing various observed material behavior as it is required.

An Advanced Cap Model for Concrete Materials

2003 ◽  
Author(s):  
C. S. Tsai ◽  
Ching-Shyang Chen ◽  
Yong-Zhang Lin ◽  
Bo-Jen Chen ◽  
J. C. Chen
Keyword(s):  
Material Behavior ◽  
Constitutive Law ◽  
Octahedral Plane ◽  
Sensitive Material ◽  
Stress Strain ◽  
Strain Relation ◽  
Stress Strain Relation ◽  
Highly Nonlinear ◽  
Cap Model ◽  
Concrete Materials

Concrete is a pressure-sensitive material. To ensure the safety of structures, it is required to understand the mechanical behavior of concrete. The stress-strain relation of concrete is highly nonlinear and pressure dependent. Therefore, design problems involving concrete materials need an appropriate constitutive model to quantify its stress-strain relation. Presented in this paper is a new cap-type constitutive law for concrete. The model is prominent in the sense that it satisfies the compatibility between the failure surface and the yield cap. It has modified the classical cap model to obtain smooth yield surfaces. In addition, the model effectively describes strength variations along various directions in the octahedral plane. The model has shown to realistically predict concrete responses in experiments by 7 parameters. The proposed concept can also be extended to include as many previous models for describing various observed material behavior as it is required.

Semi-inverse method for predicting stress–strain relationship from cone indentations

2003 ◽  
Vol 18 (9) ◽  
pp. 2068-2078 ◽  
Author(s):  
A. DiCarlo ◽  
H. T. Y. Yang ◽  
S. Chandrasekar
Keyword(s):  
A Priori ◽  
Model Material ◽  
Material Behavior ◽  
The Finite Element Method ◽  
Stress Strain ◽  
Indentation Tests ◽  
Strain Relationship ◽  
Initial Force ◽  
Relationship Of ◽  
Force Displacement

A method for determining the stress–strain relationship of a material from hardness values H obtained from cone indentation tests with various apical angles is presented. The materials studied were assumed to exhibit power-law hardening. As a result, the properties of importance are the Young's modulus E, yield strength Y, and the work-hardening exponent n. Previous work [W.C. Oliver and G.M. Pharr, J. Mater. Res. 7, 1564 (1992)] showed that E can be determined from initial force–displacement data collected while unloading the indenter from the material. Consequently, the properties that need to be determined are Y and n. Dimensional analysis was used to generalize H/E so that it was a function of Y/E and n [Y-T. Cheng and C-M. Cheng, J. Appl. Phys. 84, 1284 (1999); Philos. Mag. Lett. 77, 39 (1998)]. A parametric study of Y/E and n was conducted using the finite element method to model material behavior. Regression analysis was used to correlate the H/E findings from the simulations to Y/E and n. With the a priori knowledge of E, this correlation was used to estimate Y and n.

Forced Lateral Vibration of a Uniform Cantilever Beam With Internal and External Damping

1960 ◽  
Vol 27 (3) ◽  
pp. 551-556 ◽  
Author(s):  
Ho Chong Lee
Keyword(s):  
Steady State Response ◽  
Lateral Vibration ◽  
Rotatory Inertia ◽  
Stress Strain ◽  
Inertia Effects ◽  
State Response ◽  
Spring Element ◽  
Stress Strain Relation ◽  
Tabular Method ◽  
Strain Relationship

The steady-state response problem of a uniform beam with a sinusoidal shaking force at the base is studied for the case where the beam material is the general linear substance represented by a model having an additional spring element in parallel with the Maxwell elements. In the analysis, the stress-strain relationship is applied only to the longitudinal strain of the beam, leaving the shear stress-strain relation to be that of a perfectly elastic material. The exact solution with a numerical example is given for one case where the shear and rotatory inertia effects are neglected. This result is compared with the solution obtained by a tabular method. The results of both methods are in excellent agreement.

Multiphase Poroelastic Finite Element Models for Soft Tissue Structures

1992 ◽  
Vol 45 (6) ◽  
pp. 191-218 ◽  
Author(s):  
Bruce R. Simon
Keyword(s):  
Finite Element ◽  
Soft Tissue ◽  
Material Behavior ◽  
Constitutive Law ◽  
Finite Strains ◽  
Finite Element Models ◽  
Tissue Fluid ◽  
Biomechanical Models ◽  
Highly Nonlinear ◽  
Tissue Structures

During the last two decades, biological structures with soft tissue components have been modeled using poroelastic or mixture-based constitutive laws, i.e., the material is viewed as a deformable (porous) solid matrix that is saturated by mobile tissue fluid. These structures exhibit a highly nonlinear, history-dependent material behavior; undergo finite strains; and may swell or shrink when tissue ionic concentrations are altered. Given the geometric and material complexity of soft tissue structures and that they are subjected to complicated initial and boundary conditions, finite element models (FEMs) have been very useful for quantitative structural analyses. This paper surveys recent applications of poroelastic and mixture-based theories and the associated FEMs for the study of the biomechanics of soft tissues, and indicates future directions for research in this area. Equivalent finite-strain poroelastic and mixture continuum biomechanical models are presented. Special attention is given to the identification of material properties using a porohyperelastic constitutive law and a total Lagrangian view for the formulation. The associated FEMs are then formulated to include this porohyperelastic material response and finite strains. Extensions of the theory are suggested in order to include inherent viscoelasticity, transport phenomena, and swelling in soft tissue structures. A number of biomechanical research areas are identified, and possible applications of the porohyperelastic and mixture-based FEMs are suggested.

A Constitutive Law for Mitral Valve Tissue

1998 ◽  
Vol 120 (1) ◽  
pp. 38-47 ◽  
Author(s):  
K. May-Newman ◽  
F. C. P. Yin
Keyword(s):  
Mitral Valve ◽  
Transversely Isotropic ◽  
Quantitative Information ◽  
Substantial Improvement ◽  
Material Behavior ◽  
Constitutive Law ◽  
Highly Nonlinear ◽  
Wide Range ◽  
Mechanical Models ◽  
Biaxial Mechanical Testing

Biaxial mechanical testing and theoretical continuum mechanics analysis are employed to formulate a constitutive law for cardiac mitral valve anterior and posterior leaflets. A strain energy description is formulated based on the fibrous architecture of the tissue, accurately describing the large deformation, highly nonlinear transversely isotropic material behavior. The results show that a simple three-coefficient exponential constitutive law provides an accurate prediction of stress–stretch behavior over a wide range of deformations. Regional heterogeneity may be accommodated by spatially varying a single coefficient and incorporating collagen fiber angle. The application of this quantitative information to mechanical models and bioprosthetic development could provide substantial improvement in the evaluation and treatment of valvular disease, surgery, and replacement.

Research on Rock Mechanics Characteristics of Mud Sandstone NanTun Formation of HaiLaEr Oilfield

2014 ◽  
Vol 941-944 ◽  
pp. 2606-2610
Author(s):  
Yi Kun Liu ◽  
Yang He ◽  
Feng Jiao Wang ◽  
Yong Ping Wang ◽  
Hui Min Tang ◽  
...  
Keyword(s):  
Rock Mechanics ◽  
Clay Content ◽  
Rock Stress ◽  
Stress Strain ◽  
X Ray ◽  
Stress Strain Relation ◽  
Increasing Trend ◽  
Strain Relationship ◽  
Mechanics Characteristics ◽  
The Ideal

Hailar oilfield Nantun Formation is a set of lacustrine sedimentation, the sedimentation dominated by gravity flow,the rock contains a lot of argillaceous components. This paper analyzes the content of mud in mud sandstone in Nantun Formation by means of X-ray diffractometer, the rock mechanics parameters were measured.The results show that mud content increases with the decrease of the young's modulus, mud content increases with the increase of the Poisson's ratio; at the same time, with the increasing of the shale content, the compressive strength of rock reduce, and the tensile strength showed increasing trend; different clay contents of mud sand rock stress strain relationship is not the same, when the clay content ≤20%, rock stress strain is elastic constitutive relation, the shale content 20%-30%, the stress-strain relationship is approximate to the ideal elastic-plastic, shale content ≥30%, stress strain relation of rock strain hardening and softening of two parts including plastic deformation. Fault mud sandstone first with increasing clay content decreases, when the rock is elastic plasticity, fracture little overall change.

Surface Strain Variation in Human Patellar Tendon and Knee Cruciate Ligaments

1990 ◽  
Vol 112 (1) ◽  
pp. 38-45 ◽  
Author(s):  
D. L. Butler ◽  
M. Y. Sheh ◽  
D. C. Stouffer ◽  
V. A. Samaranayake ◽  
M. S. Levy
Keyword(s):  
Patellar Tendon ◽  
Local Strain ◽  
Surface Strain ◽  
Material Behavior ◽  
Cruciate Ligaments ◽  
Stress Strain ◽  
Strain Relationship ◽  
Strain Stress ◽  
Relationship Of ◽  
Simple Stress

Local surface strains in bone-fascicle-bone subunits from human patellar tendon and anterior and posterior cruciate ligaments were measured between markers using low-speed photography during low rate subfailure testing. A simple stress-strain relationship of the power form was found to describe the bone-to-bone responses up to four percent strain for all three tissue types examined. The regional material behavior were best fit using an inverted strain-stress relationship, however. The power model, fitted to the experimental data, conformed to the expected stress-strain relationship better than either the quadratic or cubic models. With few exceptions, for a given stress, the strains near the proximal and distal bone ends were not significantly different from each other, but were significantly higher than the strains in the tissue midregions. Local strain patterns generally varied among subunits from the same tissue.

A stress-strain relation for inelastic material behavior

1963 ◽  
Vol 275 (2) ◽  
pp. 98-106 ◽  
Author(s):  
Sharad A. Patel ◽  
B. Venkatraman ◽  
James Bentson
Keyword(s):  
Material Behavior ◽  
Stress Strain ◽  
Strain Relation ◽  
Stress Strain Relation ◽  
Inelastic Material

scholarly journals Springback Analysis in Sheet Metal Forming Using Modified Ludwik Stress-Strain Relation

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Sanjay Kumar Patel ◽  
Radha Krishna Lal ◽  
J. P. Dwivedi ◽  
V. P. Singh
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Spring Back ◽  
Stress Strain ◽  
Strain Relation ◽  
Stress Strain Relation ◽  
Strain Relationship ◽  
Von Mises ◽  
Strain Hardening Index

This paper deals with the springback analysis in sheet metal forming using modified Ludwik stress-strain relation. Using the deformation theory of plasticity, formulation of the problem and spring back ratio is derived using modified Ludwik stress strain relationship with Tresca and von Mises yielding criteraia. The results have been representing the effect of different value of or ratio, different values of Strain hardening index (), Poisson’s ratio (), and thickness on spring back ratio (). The main aim of this paper is to study the effects of the thickness, ratio, and Poisson’s ratio in spring back ratio.

Isochronous Stress-Strain Relationship in Compressive Stress Relaxation of Vulcanizates

1977 ◽  
Vol 50 (5) ◽  
pp. 915-921 ◽  
Author(s):  
B. Stenberg ◽  
J. F. Jansson
Keyword(s):  
Stress Relaxation ◽  
Mechanical Behavior ◽  
Compressive Stress ◽  
Heterogeneous Systems ◽  
Stress Strain ◽  
Vital Importance ◽  
Suspension Systems ◽  
Stress Strain Relation ◽  
Relaxation Measurements ◽  
Strain Relationship

Abstract The mechanical and other properties of natural and synthetic rubbers can be regulated by the incorporation of fillers. The mechanical behavior of the resulting complicated heterogeneous systems is often difficult to describe theoretically. These vulcanizates have wide and useful applications under conditions of multiaxial stresses. In many cases, however, the stresses act mainly in compression, for instance, in gaskets, seals, suspension systems for vibration insulation, etc. Thus the stress relaxation properties in compression are of vital importance. In spite of this, very few studies have given attention to the stress-strain relations in compression, and the results reported in the literature concentrate mainly on the mechanical behavior of rubbers in tension. We now report a study of the isochronous stress-strain relation in compression for some rubbers at 295 K, based on stress relaxation measurements. A comparison is made between the behavior of samples which have been greased and of samples which have been glued to the deformation plates.

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