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.

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.

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.

The Method of Establishing Model for Describing the Structural Constitutive Relationship of Desert Sand under Moving Vehicle

2012 ◽  
Vol 178-181 ◽  
pp. 2815-2819
Author(s):  
Wei Wei Lv ◽  
Liang Gu ◽  
Xue Tao Huang
Keyword(s):  
Constitutive Model ◽  
Soil Mechanics ◽  
Confining Pressure ◽  
Constitutive Relationship ◽  
Moving Vehicle ◽  
Military Vehicles ◽  
Desert Sand ◽  
Strength And Deformation ◽  
Relationship Of ◽  
Rock And Soil

In this paper, the way of setting up the vehicle structural constitutive model is introduceded. With the desert soil three triaxial test data of rock and soil mechanics, the soil structural quantitative parameter ( strain comprehensive structure potential ) is introduced into the soil strength and deformation characteristics analysis.Under the same confining pressure the stress-strain curves of different water content of sand have the same tendency. Through the method of setting up the Duncan-Chang model,structural constitutive model of sand is constructed and the parameters of the model are obtained by testing. The research can provide reference for vehicles and military vehicles to improve crossing through the desert sand.

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.

A Dynamic Constitutive Model of Saturated Remolded Loess

2013 ◽  
Vol 535-536 ◽  
pp. 557-560
Author(s):  
Zheng Hua Xiao ◽  
Hong Jian Liao ◽  
Akenjiang Tuohuti ◽  
Bo Han
Keyword(s):  
Constitutive Model ◽  
Rational Function ◽  
Damping Ratio ◽  
Constitutive Relationship ◽  
Triaxial Tests ◽  
Hysteresis Curve ◽  
Constant Amplitude ◽  
Symmetric Loading ◽  
Relationship Of ◽  
Curve Equation

A series of dynamic triaxial tests were performed to study a dynamic constitutive relationship of saturated remolded loess under cyclic loading. A new dynamic rational function constitutive model based on damping ratio was proposed. The model assumed the calculated damping ratio equaled to the measured damping ratio and the hysteresis curve was consisted by two curves accorded with rational function. This not only ensured that the theoretical hysteresis curve reflected the real energy dissipation of remolded loess but also retained the high calculated efficiency of this model. The hysteresis curve equation under constant amplitude symmetric loading was deduced and results of this model were verified by the tests.

scholarly journals Constitutive Modeling of the Densification Behavior in Open-Porous Cellular Solids

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2731
Author(s):  
Ameya Rege
Keyword(s):  
Constitutive Model ◽  
Cell Walls ◽  
Compressive Strain ◽  
Pore Collapse ◽  
Compressive Response ◽  
Linear Elastic ◽  
Nonlinear Springs ◽  
Different Types ◽  
Point Of Intersection ◽  
Good Agreement

The macroscopic mechanical behavior of open-porous cellular materials is dictated by the geometric and material properties of their microscopic cell walls. The overall compressive response of such materials is divided into three regimes, namely, the linear elastic, plateau and densification. In this paper, a constitutive model is presented, which captures not only the linear elastic regime and the subsequent pore-collapse, but is also shown to be capable of capturing the hardening upon the densification of the network. Here, the network is considered to be made up of idealized square-shaped cells, whose cell walls undergo bending and buckling under compression. Depending on the choice of damage criterion, viz. elastic buckling or irreversible bending, the cell walls collapse. These collapsed cells are then assumed to behave as nonlinear springs, acting as a foundation to the elastic network of active open cells. To this end, the network is decomposed into an active network and a collapsed one. The compressive strain at the onset of densification is then shown to be quantified by the point of intersection of the two network stress-strain curves. A parameter sensitivity analysis is presented to demonstrate the range of different material characteristics that the model is capable of capturing. The proposed constitutive model is further validated against two different types of nanoporous materials and shows good agreement.

The Constitutive Model for High Temperature Flow Behavior of SiC/6168Al Composite

2015 ◽  
Vol 1089 ◽  
pp. 37-41
Author(s):  
Jiang Wang ◽  
Sheng Li Guo ◽  
Sheng Pu Liu ◽  
Cheng Liu ◽  
Qi Fei Zheng
Keyword(s):  
Constitutive Model ◽  
Hot Deformation ◽  
Flow Behavior ◽  
Type Equation ◽  
Strain Rate Range ◽  
Compression Tests ◽  
Stress Strain ◽  
Hollomon Parameter ◽  
Proposed Model ◽  
Relationship Of

The hot deformation behavior of SiC/6168Al composite was studied by means of hot compression tests in the temperature range of 300-450 °C and strain rate range of 0.01-10 s-1. The constitutive model was developed to predict the stress-strain curves of this composite during hot deformation. This model was established by considering the effect of the strain on material constants calculated by using the Zenter-Hollomon parameter in the hyperbolic Arrhenius-type equation. It was found that the relationship of n, α, Q, lnA and ε could be expressed by a five-order polynomial. The stress-strain curves obtained by this model showed a good agreement with experimental results. The proposed model can accurately describe the hot flow behavior of SiC/6168Al composite, and can be used to numerically analyze the hot forming processes.

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