scholarly journals Review of Long-Term Durable Creep Performance of Geosynthetics by Constitutive Equations of Reduction Factors

Creep ◽  
2018 ◽  
Author(s):  
Han-Yong Jeon
Keyword(s):  
Constitutive Equations ◽  
Reduction Factors

scholarly journals Shaping Microstructure and Mechanical Properties of High-Carbon Bainitic Steel in Hot-Rolling and Long-Term Low-Temperature Annealing

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 384
Author(s):  
Tomasz Dembiczak ◽  
Marcin Knapiński
Keyword(s):  
Mathematical Models ◽  
Hot Rolling ◽  
Constitutive Equations ◽  
Rolling Process ◽  
Bainitic Steel ◽  
Compression Tests ◽  
High Carbon ◽  
Bainite Steel ◽  
Dilatometric Studies

Based on the research results, coefficients in constitutive equations, describing the kinetics of dynamic, meta-dynamic, and static recrystallization in high-carbon bainitic steel during hot deformation were determined. The developed mathematical model takes into account the dependence of the changing kinetics in the structural size of the preliminary austenite grains, the value of strain, strain rate, temperature, and time. Physical simulations were carried out on rectangular specimens. Compression tests with a flat state of deformation were carried out using a Gleeble 3800. Based on dilatometric studies, coefficients were determined in constitutive equations, describing the grain growth of the austenite of high-carbon bainite steel under isothermal annealing conditions. The aim of the research was to verify the developed mathematical models in semi-industrial conditions during the hot-rolling process of high-carbon bainite steel. Analysis of the semi-industrial studies of the hot-rolling and long-term annealing process confirmed the correctness of the predicted mathematical models describing the microstructure evolution.

Progress in Developing Constitutive Equations for Inelastic Design Analysis

1983 ◽  
Vol 105 (3) ◽  
pp. 273-276 ◽  
Author(s):  
C. E. Pugh
Keyword(s):  
Constitutive Equations ◽  
Inelastic Strain ◽  
Short Term ◽  
Inelastic Material ◽  
Fast Breeder Reactors ◽  
Breeder Reactors ◽  
Term Creep ◽  
Inelastic Design ◽  
Creep Deformations

A summary is given of the constitutive equations that have been developed for use in design assessments of elevated temperature components of liquid metal fast breeder reactors. The discussion addresses representations of short-term (plastic) and long-term (creep) inelastic material responses. Attention is given to improved representations of the interactions between plastic and creep deformations. Most of the discussion is in terms of constitutive equations that make use of the concept of separating the total strain into elastic, plastic, and creep portions. Additionally, some discussion is given of progress being made toward establishing design equations based on unified measures of inelastic strain that do not distinguish different strain portions.

scholarly journals Effect of acids and alkalis on the resistance of a polypropylene geotextile against thermo-oxidation

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Jose Ricardo Carneiro ◽  
Paulo Joaquim Almeida ◽  
Maria de Lurdes Lopes
Keyword(s):  
Tensile Strength ◽  
Sodium Hydroxide ◽  
Sulphuric Acid ◽  
Reduction Factor ◽  
Strength Reduction ◽  
Combined Effect ◽  
Tensile Behaviour ◽  
Degradation Tests ◽  
Reduction Factors

The long-term behaviour of geosynthetics is one of the most important topics in the research about these materials. This work studies the effect of some liquids (water, sulphuric acid 0.1 mol.L-1 and sodium hydroxide 0.1 mol.L-1) in the resistance of a polypropylene geotextile against thermo-oxidation. For that purpose, the geotextile was (1) exposed in isolation to the liquids (immersion tests) and to thermo-oxidation (oven-ageing tests) and (2) exposed consecutively to both degradation tests (combined effect). The damage suffered by the geotextile in the degradation tests was evaluated by monitoring changes in its tensile behaviour. Based on the changes occurred in tensile strength, reduction factors were determined. The reduction factors obtained in the successive exposures to liquids and thermo-oxidation were compared with the reduction factors determined by the traditional methodology for the combined effect of those agents. The results, among other findings, showed the existence of an effect of sulphuric acid 0.1 mol.L-1 in the resistance of the geotextile against thermo-oxidation. Indeed, the successive exposure to sulphuric acid 0.1 mol.L-1 and thermo-oxidation (two agents that individually did not cause relevant damage) led to some degradation. Due to the interaction occurred between the degradation agents, the traditional methodology was unable to predict correctly (by underestimating) the reduction factor for the combined effect of sulphuric acid 0.1 mol.L-1 and thermo-oxidation.

scholarly journals Laboratory Evaluation of Interactions in the Degradation of a Polypropylene Geotextile in Marine Environments

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
José Ricardo Carneiro ◽  
Paulo Joaquim Almeida ◽  
Maria de Lurdes Lopes
Keyword(s):  
Strength Reduction ◽  
Laboratory Evaluation ◽  
Marine Environments ◽  
Engineering Structures ◽  
Artificial Weathering ◽  
Multiple Exposures ◽  
Degradation Tests ◽  
Degradation Test ◽  
Reduction Factors

The long-term behaviour of geosynthetics applied in coastal engineering structures can be adversely affected by many agents. This paper studies the resistance of a nonwoven polypropylene geotextile against some degradation agents present in marine environments and evaluates the existence of interactions between them. For that purpose, the geotextile was exposed to some laboratory degradation tests: immersion tests (in seawater, deionised water, and sodium chloride 35 g·L−1), thermooxidation, and artificial weathering. The geotextile was (1) exposed separately to each degradation test and (2) exposed successively to combinations of two or three degradation tests. The damage caused by the degradation tests was evaluated by monitoring the tensile properties of the geotextile. Based on the changes occurred in tensile strength, reduction factors were determined. The reduction factors obtained directly in the multiple exposures were compared with those obtained by the traditional methodology for the combined effect of the degradation agents. The results, among other findings, showed the existence of relevant interactions between the degradation agents and showed that the reduction factors obtained by the traditional methodology were unable to represent accurately (by underestimating) the degradation occurred in the geotextile.

Irreversible (rational) thermodynamics of mixtures of a solid substance with chemically reacting fluids

1988 ◽  
Vol 53 (8) ◽  
pp. 1620-1635 ◽  
Author(s):  
Nguyen Xuan Quang ◽  
Ivan Samohýl ◽  
Ho Si Thoang
Keyword(s):  
Heat Conduction ◽  
Constitutive Equations ◽  
Long Term Memory ◽  
Solid Substance ◽  
Term Memory ◽  
Internal Parameters ◽  
Non Linear ◽  
Thermodynamics Of Mixtures ◽  
Chemically Reacting

The method of rational thermodynamics of Truesdell's school (non-linear thermomechanics of continuum) has been applied to mixtures of a solid substance with chemically reacting fluids. The kinematics, balances, and stoichiometry in such mixtures are formulated, and constitutive equations are proposed involving the effects of diffusion, heat conduction, and long-term memory expressed by internal parameters. The final form of the constitutive equations has been obtained by applying the constitutive entropic principle of Coleman and Noll. The equilibrium in the mixture is discussed.

scholarly journals Evaluation of the long-term performance of geosynthetic reinforcements from their reduction factors

2006 ◽  
Vol 25 (3) ◽  
pp. 289-295 ◽  
Author(s):  
Han-Yong Jeon ◽  
Seong Hun Kim ◽  
Won Seok Lyoo ◽  
Chungsik Yoo ◽  
George R. Koerner
Keyword(s):  
Long Term Performance ◽  
Term Performance ◽  
Reduction Factors

Analysis of long-term creep curves by constitutive equations

2009 ◽  
Vol 510-511 ◽  
pp. 190-194 ◽  
Author(s):  
K. Sawada ◽  
M. Tabuchi ◽  
K. Kimura
Keyword(s):  
Constitutive Equations ◽  
Creep Curves ◽  
Term Creep
Sign in / Sign up

Export Citation Format

Share Document