scholarly journals Constitutive Modeling of Physical Properties of Coastal Sand during Tunneling Construction Disturbance

2021 ◽  
Vol 9 (2) ◽  
pp. 167
Author(s):  
Jian-Feng Zhu ◽  
Hong-Yi Zhao ◽  
Ri-Qing Xu ◽  
Zhan-You Luo ◽  
Dong-Sheng Jeng
Keyword(s):  
Constitutive Model ◽  
Constitutive Relationship ◽  
Initial Void Ratio ◽  
Coastal Cities ◽  
Disturbed State Concept ◽  
Strain Relationship ◽  
Internal Angle ◽  
Concept Theory ◽  
Relationship Of ◽  
Disturbance Function

This paper presents a simple but workable constitutive model for the stress–strain relationship of sandy soil during the process of tunneling construction disturbance in coastal cities. The model was developed by linking the parameter K and internal angle φ of the Duncan–Chang model with the disturbed degree of sand, in which the effects of the initial void ratio on the strength deformation property of sands are considered using a unified disturbance function based on disturbed state concept theory. Three cases were analyzed to investigate the validity of the proposed constitutive model considering disturbance. After validation, the proposed constitutive model was further incorporated into a 3D finite element framework to predict the soil deformation caused by shield construction. It was found that the simulated results agreed well with the analytical solution, indicating that the developed numerical model with proposed constitutive relationship is capable of characterizing the mechanical properties of sand under tunneling construction disturbance.

scholarly journals Simulating the Stress-Strain Relationship of Geomaterials by Support Vector Machine

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Hongbo Zhao ◽  
Zenghui Huang ◽  
Zhengsheng Zou
Keyword(s):  
Support Vector Machine ◽  
Constitutive Relationship ◽  
Support Vector ◽  
Nonlinear Relationship ◽  
Ann Model ◽  
Stress Strain ◽  
Svm Model ◽  
Strain Relationship ◽  
Artificial Neural Network Ann ◽  
Relationship Of

Stress-strain relationship of geomaterials is important to numerical analysis in geotechnical engineering. It is difficult to be represented by conventional constitutive model accurately. Artificial neural network (ANN) has been proposed as a more effective approach to represent this complex and nonlinear relationship, but ANN itself still has some limitations that restrict the applicability of the method. In this paper, an alternative method, support vector machine (SVM), is proposed to simulate this type of complex constitutive relationship. The SVM model can overcome the limitations of ANN model while still processing the advantages over the traditional model. The application examples show that it is an effective and accurate modeling approach for stress-strain relationship representation for geomaterials.

A Constitutive Model for Thixotropic Plastic Forming of Composites

2010 ◽  
Vol 154-155 ◽  
pp. 690-693 ◽  
Author(s):  
Hong Yan ◽  
Jian Jin Wang ◽  
Fa Yun Zhang
Keyword(s):  
Constitutive Model ◽  
Solid Metal ◽  
Constitutive Relationship ◽  
Practical Significance ◽  
Forecast Precision ◽  
Plastic Forming ◽  
Nonlinear Regression Method ◽  
Semi Solid ◽  
Relationship Of ◽  
Good Agreement

A new constitutive model for semi-solid composites forming was derived with analyzing constitutive relationships of semi-solid metal and composites forming. Parameters in the constitutive model were determined by the multiple nonlinear regression method. A constitutive relationship of semi-solid SiCp/AZ61 composites thixotropic plastic forming was proposed. The calculated results were good agreement with the experimental ones. The proposed constitutive model has the higher forecast precision and practical significance. The construction of constitutive model provides references for the thixotropic forming theory, simulation and technology.

Experimental Research on the Stress - Strain Curve of Regional Confined Concrete under Single Axial Press

2014 ◽  
Vol 584-586 ◽  
pp. 1289-1292
Author(s):  
Guo Liang Zhu
Keyword(s):  
Mechanical Properties ◽  
Theoretical Analysis ◽  
Constitutive Model ◽  
Theoretical Basis ◽  
Strain Curve ◽  
Confined Concrete ◽  
Constitutive Relationship ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Relationship Of

Regional confined concrete is base on confined concrete. It is the theory and application of a new attempt and development on confined concrete. To apply it to the actual project, we need to research mechanical properties and establish constitutive relationship of regional confined concrete. According to the research, we had carried on a series of tests, founded the stress-strain constitutive model of regional confined concrete under single axial press. The accuracy of theoretical analysis were more fully verified , and a theoretical basis for the application was provided.

Constitutive Modeling for Porous PLGA 85/15 Scaffold in Compression

2006 ◽  
Author(s):  
Linus Leung ◽  
Josee Perron ◽  
Hani E. Naguib
Keyword(s):  
Constitutive Model ◽  
Constitutive Modeling ◽  
Saturation Pressure ◽  
Mass Ratio ◽  
Compressive Behavior ◽  
Stress Strain ◽  
Salt Leaching ◽  
Strain Relationship ◽  
Relationship Of ◽  
Gas Foaming

Constitutive modeling of stress-strain relationship of open-celled PLGA 85/15 foams under compression was studied. A constitutive model for compressive behavior was directly derived from the morphology of a unit cubic cell. These constitutive equations describe the stress-strain relationship as a function of the foam's material properties and cell morphology, such as elastic modulus, yield stress, relative density, cell strut thickness, and cell size. To verify this model, uniaxial compression testing was performed on foam samples. Using the gas foaming/salt leaching method, the samples were prepared by using different foaming parameters such as salt/polymer mass ratio, saturation pressure, and saturation time. The comparisons of theoretical and experimental data demonstrate that the constitutive model using a cubic unit cell accurately describes the behavior of PLGA foams with low relative densities under compression.

A Statistical Constitutive Model for the Strength of Brittle Fiber at Different Strain Rates

2010 ◽  
Vol 152-153 ◽  
pp. 1213-1216
Author(s):  
Wen Huang ◽  
Zhong Wei Huang
Keyword(s):  
Constitutive Model ◽  
Strain Rate ◽  
Tensile Tests ◽  
Fiber Bundles ◽  
Strain Rates ◽  
Stress Strain ◽  
Sic Fiber ◽  
Brittle Fiber ◽  
Strain Relationship ◽  
Relationship Of

A statistical constitutive model, which takes account the effect of strain rate, was presented to describe the stress-strain relationship of brittle fiber bundles. To verify its reliability, tensile tests on two kinds of brittle fibers: glass fiber and SiC fiber, were carried out at different strain rates, and the stress-strain curves were obtained. It was found that the modulus E, the strength and the fracture strain of these fiber bundles all increase with increasing strain rate. The simulated stress-strain curves, derived from the constitutive model, fit the tested results well, which indicates that the model is valid and reliable.

scholarly journals Damage constitutive model of stratified cemented backfill based on coupling macroscopic and mesoscopic deformations

2020 ◽  
Vol 194 ◽  
pp. 05024
Author(s):  
Yanan Tang ◽  
Weidong Song ◽  
Jianxin Fu
Keyword(s):  
Mechanical Properties ◽  
Constitutive Model ◽  
Compressive Load ◽  
Strain Curve ◽  
Strength Distribution ◽  
Stress Strain ◽  
Strain Relationship ◽  
Damage Constitutive Model ◽  
Stratified Structure ◽  
Relationship Of

The mechanical properties and stress-strain relationship of cemented backfills with different stratified structure have a direct effect on the mining-filling cycle and the mining of adjacent pillars. To obtain the stress-strain evolution curves, the uniaxial compressive strength tests were performed on backfills with stratified numbers of 0, 1, 2 and 3. The deformation of stratified backfill under the compressive load is regarded as a compound of closed deformation of the macroscopic stratified structure and elastic deformation of material. The damage constitutive model of cemented backfills with different stratified structure are established by considering the influence of compacted section. Comparative analysis reveals that the calculated curve based on the established sectional damage constitutive model conforms well to the trial curve. The maximum closed strain of the structural plane has a more significant effect on the mechanical properties of backfill. In the Weibull distribution, with the increase of the parameter m, the peak strength of backfill gradually increases and then reaches to a certain value, and the stress-strain curve gradually becomes steeper, which shows that m is a reflection of the concentration level of micro-unit strength distribution in the backfill..

Research on Compressive Stress - Strain Relationship of Fiber Reinforced Concrete

2010 ◽  
Vol 168-170 ◽  
pp. 384-392 ◽  
Author(s):  
Tie Cheng Wang ◽  
Hai Long Zhao ◽  
Jin Jin Hao ◽  
Jian Quan Zu
Keyword(s):  
Reinforced Concrete ◽  
Constitutive Model ◽  
Engineering Application ◽  
Fiber Reinforced Concrete ◽  
Constitutive Relationship ◽  
Peak Strain ◽  
Test Results ◽  
Fiber Reinforced ◽  
Damage Constitutive Model ◽  
Relationship Of

The marked brittleness of concrete could be overcome by the addition of fibers. This paper experimentally investigated the mechanical properties and constitutive relationship of different fiber reinforced concrete. It is shown from the results that the compressive strength and peak strain of concrete with fiber have little improvement, but the ultimate strain, deformation capacity, toughness and energy dissipation capacity are improved greatly. The damage constitutive model recommended by the emendatory code for design of concrete structure (appendix C) (GB50010-2002) is applied for calculations and analyses according to the test results. The damage constitutive model and non-elastic constitutive model of different fiber reinforced concrete are established based on the test results. It is indicated from the analyses that the constitutive models established in this paper are in accordance with the characteristic of the fiber reinforced concrete in loading process. The damage constitutive model in appendix C in code could be applied directly in some low precision calculation and engineering application.

Plasticity Constitutive Model for Stress-Strain Relationship of Confined Concrete

2017 ◽  
Vol 114 (2) ◽  
Author(s):  
Bambang Piscesa ◽  
Mario M. Attard ◽  
Ali Khajeh Samani ◽  
Sawekchai Tangaramvong
Keyword(s):  
Constitutive Model ◽  
Confined Concrete ◽  
Stress Strain ◽  
Strain Relationship ◽  
Relationship Of

scholarly journals Investigation of the Constitutive Model of W/PMMA Composite Microcellular Foams

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1136 ◽  
Author(s):  
Yuxuan Zhu ◽  
Guoqiang Luo ◽  
Ruizhi Zhang ◽  
Qiwen Liu ◽  
Yi Sun ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Constitutive Model ◽  
Constitutive Relationship ◽  
Microcellular Foam ◽  
Melt Mixing ◽  
Static Compression ◽  
Microcellular Foams ◽  
Static Mechanical ◽  
Relationship Of ◽  
Quasi Static Compression

Investigating the constitutive relationship of a material can provide better understanding of the mechanical properties of a material and has an irreplaceable effect on optimizing the performance of a material. This paper investigated a constitutive model for tungsten/polymethyl-methacrylate (W/PMMA) composite microcellular foams prepared by using melt mixing and supercritical carbon dioxide foaming. The stress-strain relationships of these foams with different W contents were measured under static compression. The elastic modulus and compressive strength values of the foams were remarkably greater than those of the pure PMMA foams: at a W content of 20 wt %, these values were increased by 269.1% and 123.9%, respectively. Based on the Maxwell constitutive model, the relevant coefficients were fitted according to the experimental data of different relative densities and W contents in quasi-static compression. According to the numerical relationships between the relevant coefficients and the relative densities and W contents, the quasi-static mechanical constitutive model of W/PMMA composite microcellular foams with W contents of 0~60 wt % and relative densities of 0.15~0.55 were predicted. This study provided basic data for the optimal design of the W/PMMA composite microcellular foams and proposed a method for investigating the mechanical properties of composite microcellular foam materials.

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