Constitutive Modeling of Ratchetting Effects—Part I: Experimental Facts and Properties of the Classical Models

1989 ◽  
Vol 111 (4) ◽  
pp. 384-392 ◽  
Author(s):  
J. L. Chaboche ◽  
D. Nouailhas
Keyword(s):  
Constitutive Modeling ◽  
Constitutive Equations ◽  
Cyclic Plasticity ◽  
Strain Accumulation ◽  
The Past ◽  
Secondary Load ◽  
Great Progress ◽  
Classical Models ◽  
Progressive Strain ◽  
Primary Load

The constitutive modeling of cyclic plasticity has made great progress during the past twenty years. One of the incompletely solved problems concerns ratchetting, that is the progressive strain accumulation, cycle-by-cycle, induced by the superposition of a cyclic secondary load to a constant primary load. The paper discusses the main experimental facts and identifies the main inadequacies of the classical cyclic constitutive equations when they are used to predict ratchetting effects.

scholarly journals Self-Cleaning Concretes: An Overview

2020 ◽  
Vol 1 (2) ◽  
pp. 6-12
Author(s):  
ilker bekir topçu
Keyword(s):  
Air Pollution ◽  
Building Materials ◽  
Civil Engineering ◽  
Effective Solution ◽  
Concrete Technology ◽  
Engineering Studies ◽  
The Past ◽  
Great Progress ◽  
Self Cleaning ◽  
Mineral Additives

Many studies have been carried out on the problems of civil engineering with the change of human problems today and in the past. These studies contributed to the development of concrete technology. Concrete is an important building material consisting of mixing aggregate, cement and water with or without chemical and mineral additives since the first day of use. Concrete technology has made great progress and continues. With developing concrete technology, self-cleaning concretes have emerged. Many studies have been conducted on self-cleaning concretes by researchers. This article reviews the research published on self-cleaning concretes and presents its role in reducing environmental pollution and its place in future engineering studies. When we look at the studies on self-cleaning concretes that emerged as a result of the developments in concrete technology, it is seen that the developments have progressed considerably. Contemporary civil engineering has provided a highly effective solution for the solution of modern problems. Environmentally friendly building materials will fulfil their duty in reducing air pollution, one of the biggest problems of our time. Self-cleaning buildings and roads that reduce pollution may sound like futuristic ideas, but it is not far away to encounter these structures more widely in our country and our world.

Emulsion templated advanced functional materials from emerging nano building blocks

2021 ◽  
Author(s):  
Chenfei Yao ◽  
Ge Shi ◽  
Yijie Hu ◽  
Hao Zhuo ◽  
Zehong Chen ◽  
...  
Keyword(s):  
Transition Metal ◽  
Functional Materials ◽  
Building Blocks ◽  
Metal Carbides ◽  
Transition Metal Carbides ◽  
The Past ◽  
Great Progress

The development of emulsion templated functional materials has achieved great progress in the past decades in academic and industrial fields. Recently, new building blocks such as graphene, transition metal carbides...

An Integrative Approach to the Assessment and Treatment of Inflammatory Conditions

2017 ◽  
Author(s):  
Mark Liponis ◽  
Bettina Martin
Keyword(s):  
Integrative Approach ◽  
The Past ◽  
Inflammatory Conditions ◽  
Improved Outcomes ◽  
Targeted Treatments ◽  
Great Progress ◽  
Assessment And Treatment ◽  
The Many ◽  
Made In

The past two decades have seen great progress in recognizing the importance of inflammation in medicine. Increased focus on inflammation in both prevention and treatment has improved outcomes and quality of life in chronic diseases. Science has improved our understanding of inflammation’s many causes and effects on health, and many advances have been made in the availability of targeted therapeutic options for treating inflammation. This chapter gives an overview of recognizing the many causes of inflammation, its many targeted treatments strategies, and the questions that still surround it. It discusses several integrative approaches to reducing inflammation, including exercise, diet, and different strategies for managing sleep, mood, and stress, such as meditation and massage.

scholarly journals High Pressure Experiments for Astrophysics

1994 ◽  
Vol 147 ◽  
pp. 239-271
Author(s):  
P. Loubeyre
Keyword(s):  
High Pressures ◽  
Dense Matter ◽  
Planetary Interiors ◽  
The Past ◽  
Dynamic Methods ◽  
Great Progress ◽  
Astrophysical Objects ◽  
Low Mass ◽  
Plasma Phase ◽  
Very High

AbstractIn the past decade, measurements of the properties of H2 and He systems at very high pressures have made great progress, now reaching density at the limit of the plasma phase transition of hydrogen. The potentialities and limits of static and dynamic methods will be reviewed. Then, a survey of the major experimental results is presented. It is the intention of this article to show how these measurements can bring information to model low-mass astrophysical objects. Three levels of usefulness are distinguished on selected examples: data for codes of planetary interiors, constraints for theoretical descriptions of dense matter, observations of unsuspected properties at very high density.

Modelling of Cyclic Plasticity With Unified Constitutive Equations: Improvements in Simulating Normal and Anomalous Bauschinger Effects

1980 ◽  
Vol 102 (2) ◽  
pp. 215-222 ◽  
Author(s):  
A. K. Miller
Keyword(s):  
Constitutive Equations ◽  
Work Hardening ◽  
Hysteresis Loops ◽  
Experimental Tests ◽  
Cyclic Hardening ◽  
Back Stress ◽  
Cyclic Softening ◽  
Cyclic Plasticity ◽  
Dislocation Loops ◽  
Work Hardening Coefficient

In simulating cyclic plasticity with several existing “unified” constitutive equations, the predicted hysteresis loops are “oversquare” with respect to experimentally-observed behavior. To eliminate this shortcoming in the constitutive equations developed by the present author, the work-hardening coefficient in the equation controlling the back stress (R) has been made a function of the back stress itself and the sign of the effective modulus-compensated stress σ/E – R. This improvement results in simulated hysteresis loops whose curvature closely resembles that in experimental tests. The improvement preserves all of the previously demonstrated capabilities such as cyclic hardening, cyclic hardening, cyclic softening, etc. The same equations can also simulate some unusual experimentally-observed Bauschinger effects involving local reversals in curvature. The curvature reversals in the simulations result from strain softening of the isotropic work-hardening variable in the equations. The physical significance of the behavior of the constitutive equations is discussed in terms of annihilation of previously-generated dislocation loops by reversing dislocations and experimentally-observed decreases in dislocation density and dissolution of cell walls upon stress reversal.

Modelling of Cyclic Plasticity and Viscoplasticity of Directionally Solified DZ125 Superalloy: Part I: Estimating the Parameters of Chaboche Constitutive Equations

2011 ◽  
Vol 295-297 ◽  
pp. 854-858
Author(s):  
Jie Qiong Li ◽  
Li Jun Wang
Keyword(s):  
Constitutive Model ◽  
Test Data ◽  
Creep Test ◽  
Constitutive Equations ◽  
Least Square ◽  
Cyclic Plasticity ◽  
Initial Material ◽  
Material Parameters ◽  
Cyclic Relaxation ◽  
Least Square Procedure

Cyclic plasticity and viscoplasticity of directionally solified superalloy, DZ125, have been described using the Chaboche unified constitutive model. A set of initial material parameters has been determined utilizing the monotonic, cyclic, relaxation and creep test data of DZ125 at 980°C, while an optimum set of material parameters has been obtained by means of least-square procedure.

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