scholarly journals A Constitutive Model for Overconsolidated Structured Soils Using Structural Variable

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Wugang Li ◽  
Wenhua Liu ◽  
Zhijia Xue ◽  
Xiuli Sun
Keyword(s):  
Constitutive Model ◽  
Mechanical Behavior ◽  
Soil Structure ◽  
The Novel ◽  
Structural Index ◽  
Structural Variable ◽  
Compression Behavior ◽  
Structured Soils ◽  
Structured Soil ◽  
Compression Line

Due to the influence of soil structure, structured soils exhibit significantly different mechanical behavior compared to the reconstituted soils having the same material. In this work, a theoretical analysis focusing on the mechanical behavior of structured soils is presented. Based on the mechanical behavior of the structured soil, a newly defined variable structural index was used as a measurement of the integrity of soil structure based on the concept of intrinsic compression line of intact structured soils. Furthermore, a novel correlation for the variation in volume of structured soils is established using effective stress and newly defined structural index as the constitutive variables. The novel correlation provided interpretation about the mechanism of compression behavior of the structured soils. Afterwards, the proposed correlation for the variation in volume was extended to triaxial stress state in the framework of subloading surface to include the effect of overconsolidation. Comparisons between the predictions and experimental results validated the proposed constitutive model for structured soils.

An Oedometer-Based Method for Preparing Reconstituted Clay Samples

2015 ◽  
Vol 719-720 ◽  
pp. 193-196
Author(s):  
Jie Yin ◽  
Yong Hong Miao
Keyword(s):  
Mechanical Behavior ◽  
Soil Structure ◽  
Large Diameter ◽  
Soft Clay ◽  
Soil Samples ◽  
Improved Method ◽  
Structured Soils ◽  
Reconstituted Soil ◽  
Natural Clays

It is well known that the mechanical behavior of the natural intact soft clay is usually quite different from that of the reconstituted counterpart. Hence, how to predict the influences of soil structure on the mechanical behavior of natural clays is an important issue in geotechnical engineering.The mechanical behavior of structured soils can usually be quantitatively assessed based on the mechanical behavior obtained from corresponding reconstituted clays. The preparing method for reconstituted soils will affect the quality of reconstituted samples greatly, and therefore, affect their mechanical parameter. To guarantee the quality of reconstituted soil samples, a large diameter oedometer apparatus is developed. Also, an oedomer-based method for preparing reconstituted clay samples is proposed. Typical soft Lianyungang city clay from China is chosen to testify the methods and corresponding procedures. The feasibility of the improved method is confirmed by comparing its results with those of the normal oedometer test.

scholarly journals Numerical Implementation of a Hydro-Mechanical Coupling Constitutive Model for Unsaturated Soil Considering the Effect of Micro-Pore Structure

2021 ◽  
Vol 11 (12) ◽  
pp. 5368
Author(s):  
Guoqing Cai ◽  
Bowen Han ◽  
Mengzi Li ◽  
Kenan Di ◽  
Yi Liu ◽  
...  
Keyword(s):  
Constitutive Model ◽  
Mechanical Behavior ◽  
Pore Structure ◽  
Unsaturated Soil ◽  
Fortran Program ◽  
Numerical Implementation ◽  
Numerical Application ◽  
Integration Algorithm ◽  
Mechanical Coupling ◽  
Numerical Program

An unsaturated soil constitutive model considering the influence of microscopic pore structure can more accurately describe the hydraulic–mechanical behavior of unsaturated soil, but its numerical implementation is more complicated. Based on the fully implicit Euler backward integration algorithm, the ABAQUS software is used to develop the established hydro-mechanical coupling constitutive model for unsaturated soil, considering the influence of micro-pore structure, and a new User-defined Material Mechanical Behavior (UMAT) subroutine is established to realize the numerical application of the proposed model. The developed numerical program is used to simulate the drying/wetting cycle process of the standard triaxial specimen. The simulation results are basically consistent with those calculated by the Fortran program, which verifies the rationality of the developed numerical program.

A Method for Predicting the Behavior of Plastics at Different Temperatures

2014 ◽  
Vol 1039 ◽  
pp. 107-111
Author(s):  
Yang Chen ◽  
Gui Qin Li ◽  
Bin Ruan ◽  
Xiao Yuan ◽  
Hong Bo Li
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Constitutive Model ◽  
Research And Development ◽  
Mechanical Behavior ◽  
Plastic Material ◽  
Different Temperatures ◽  
Plastic Parts

The mechanical behavior of plastic material is dramatically sensitive to temperature. An method is proposed to predict the mechanical behavior of plastics for cars, ranging from low-temperature low temperature ≤-40°C to high temperature ≥80°C. It dominates the behavior of plastic material based on improved constitutive model in which the parameters adjusted by a series of tests under different temperatures. The method is validated with test and establishes the basis for research and development of plastic parts for automobile as well.

Implementation of a soil-structure interface constitutive model for application in geo-structures

2019 ◽  
Vol 116 ◽  
pp. 714-731 ◽  
Author(s):  
Miad Saberi ◽  
Charles-Darwin Annan ◽  
Jean-Marie Konrad
Keyword(s):  
Constitutive Model ◽  
Soil Structure

scholarly journals Extension of Flow Behaviour and Damage Models for Cast Iron Alloys with Strain Rate Effect

2020 ◽  
Author(s):  
Chuang Liu ◽  
Dongzhi Sun ◽  
Xianfeng Zhang ◽  
Florence Andrieux ◽  
Tobias Gerster
Keyword(s):  
Cast Iron ◽  
Constitutive Model ◽  
Strain Rate ◽  
Mechanical Behavior ◽  
Damage Model ◽  
Iron Alloys ◽  
Strain Rate Range ◽  
Strain Rates ◽  
Damage Models ◽  
Rate Dependent

Abstract Cast iron alloys with low production cost and quite good mechanical properties are widely used in the automotive industry. To study the mechanical behavior of a typical ductile cast iron (GJS-450) with nodular graphite, uni-axial quasi-static and dynamic tensile tests at strain rates of 10− 4, 1, 10, 100, and 250 s− 1 were carried out. In order to investigate the effects of stress state, specimens with various geometries were used in the experiments. Stress–strain curves and fracture strains of the GJS-450 alloy in the strain-rate range of 10− 4 to 250 s− 1 were obtained. A strain rate-dependent plastic flow law based on the Voce model is proposed to describe the mechanical behavior in the corresponding strain-rate range. The deformation behavior at various strain rates is observed and analyzed through simulations with the proposed strain rate-dependent constitutive model. The available damage model from Bai and Wierzbicki is extended to take the strain rate into account and calibrated based on the analysis of local fracture strains. The validity of the proposed constitutive model including the damage model was verified by the corresponding experimental results. The results show that the strain rate has obviously nonlinear effects on the yield stress and fracture strain of GJS-450 alloys. The predictions with the proposed constitutive model and damage models at various strain rates agree well with the experimental results, which illustrates that the rate-dependent flow rule and damage models can be used to describe the mechanical behavior of cast iron alloys at elevated strain rates.

scholarly journals Experimental results and constitutive model of the mechanical behavior of Ti6Al4V alloy at high temperature

2019 ◽  
Vol 41 ◽  
pp. 723-730
Author(s):  
Jorge Ayllón Perez ◽  
Valentín Miguel Eguía ◽  
Juana Coello Sobrino ◽  
Alberto Martínez Martínez
Keyword(s):  
High Temperature ◽  
Constitutive Model ◽  
Mechanical Behavior ◽  
Ti6al4v Alloy ◽  
Experimental Results

scholarly journals A Constitutive Model for the Mechanical Behavior of Single Crystal Silicon at Elevated Temperature

2001 ◽  
Vol 687 ◽  
Author(s):  
H.-S. Moon ◽  
L. Anand ◽  
S. M. Spearing
Keyword(s):  
High Temperature ◽  
Constitutive Model ◽  
Single Crystal ◽  
Mechanical Behavior ◽  
Elevated Temperatures ◽  
Single Crystal Silicon ◽  
Operational Environment ◽  
Localized Deformation ◽  
Creep Tests ◽  
Crystal Silicon

AbstractSilicon in single crystal form has been the material of choice for the first demonstration of the MIT microengine project. However, because it has a relatively low melting temperature, silicon is not an ideal material for the intended operational environment of high temperature and stress. In addition, preliminary work indicates that single crystal silicon has a tendency to undergo localized deformation by slip band formation. Thus it is critical to obtain a better understanding of the mechanical behavior of this material at elevated temperatures in order to properly exploit its capabilities as a structural material. Creep tests in simple compression with n-type single crystal silicon, with low initial dislocation density, were conducted over a temperature range of 900 K to 1200 K and a stress range of 10 MPa to 120 MPa. The compression specimens were machined such that the multi-slip <100> or <111> orientations were coincident with the compression axis. The creep tests reveal that response can be delineated into two broad regimes: (a) in the first regime rapid dislocation multiplication is responsible for accelerating creep rates, and (b) in the second regime an increasing resistance to dislocation motion is responsible for the decelerating creep rates, as is typically observed for creep in metals. An isotropic elasto-viscoplastic constitutive model that accounts for these two mechanisms has been developed in support of the design of the high temperature turbine structure of the MIT microengine.

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