Free Energy of Damaged Solids

2014 ◽  
Vol 1049-1050 ◽  
pp. 1741-1746
Author(s):  
Ji Zhang
Keyword(s):  
Free Energy ◽  
Elastic Energy ◽  
Driving Force ◽  
Damage Evolution ◽  
Damage Mechanics ◽  
Solid Mechanics ◽  
Constitutive Models ◽  
Traditional Fields ◽  
State Functions

This paper examines the free energy potentials of damaged solids for the construction of damage mechanics constitutive models. The physical meaning of free energy in solid mechanics is analyzed in contrast with that in traditional fields of thermodynamics; 1D stress-strain curves are used to show the relationships between various thermodynamic state functions in isothermal loading processes; and the role of plastic free energy in damage evolution is discussed both macroscopically and microscopically. It is concluded that plastic free energy, which is a macroscopic representation of some additional microscopic elastic energy, cannot do work during unloading but get released when damage takes place, constituting part of the driving force for damage evolution.

Development of “Material Specific” Creep Continuum Damage Mechanics-Based Constitutive Equations

2020 ◽  
Author(s):  
Ricardo Vega ◽  
Jaime A. Cano ◽  
Calvin M. Stewart
Keyword(s):  
Constitutive Model ◽  
Strain Rate ◽  
Creep Strain ◽  
Creep Deformation ◽  
Damage Evolution ◽  
Damage Mechanics ◽  
Constitutive Models ◽  
Continuum Damage Mechanics ◽  
Creep Strain Rate ◽  
Continuum Damage

Abstract The objective of this study is to introduce a method for creating “material specific” creep continuum damage mechanics-based constitutive models. Herein, material specific is defined as a constitutive model based on the mechanism-informed minimum creep strain rate (MCSR) equations found in deformation mechanism maps and calibrated to available material data. The material specific models are created by finding the best MCSR model for a dataset. Once the best MCSR model is found, the Monkman Grant inverse relationship between the MCSR and rupture time is employed to derive a rupture equation. The equations are substituted into continuum damage mechanics-based creep strain rate and damage evolution equations to furnish predictions of creep deformation and damage. Material specific modeling allows for the derivation of creep constitutive models that can better the material behavior specific to the available data of a material. The material specific framework is also advantageous since it has a systematic framework that moves from finding the best MCSR model, to rupture time, to damage evolution and, creep strain rate. Data for Alloy P91 was evaluated and a material specific constitutive model derived. The material specific model was able to accurately predict the MCSR, creep deformation, damage, and rupture of alloy P91.

Economic Growth: New Problems and New Risks

2006 ◽  
pp. 20-37 ◽  
Author(s):  
M. Ershov
Keyword(s):  
Economic Growth ◽  
Foreign Exchange ◽  
Driving Force ◽  
Structural Changes ◽  
Rate Of Growth

The economic growth, which is underway in Russia, raises new questions to be addressed. How to improve the quality of growth, increasing the role of new competitive sectors and transforming them into the driving force of growth? How can progressive structural changes be implemented without hampering the rate of growth in general? What are the main external and internal risks, which may undermine positive trends of development? The author looks upon financial, monetary and foreign exchange aspects of the problem and comes up with some suggestions on how to make growth more competitive and sustainable.

La politique forestière vaudoise: une orientation résolument «patrimoine multifonctionnel» | Forestry policy in the canton of Vaud: the “multifunctional heritage” option

2011 ◽  
Vol 162 (7) ◽  
pp. 209-215
Author(s):  
Jean-François Métraux
Keyword(s):  
Driving Force ◽  
Management Plan ◽  
The Political ◽  
Wood Production ◽  
Forest Owners ◽  
Forestry Policy ◽  
Forestry Management ◽  
Political Decisions ◽  
Forest Managers

In the years since 2000, the authorities in charge of forests in canton Vaud have made some substantial changes as a reaction to the political decisions arising from the Swiss Forest Programme and the projected revision of the Federal forestry Law, as well as to the deterioration of the economic situation in forestry enterprises. This article gives a survey of the directions taken. Thus the canton recognises the primordial role of wood production as a driving force behind the creation of a multifunctional forest. The Service for Forests, Wildlife and Nature has invested a great deal in planning, and has redefined the management plan to be an instrument intended for forest owners and forest managers. The canton has innovated by introducing forestry groups and a scheme of equalisation of forestry costs between communes. Hence the conception of forestry management in canton Vaud is resolutely that of a multifunctional natural heritage.

Conclusion

2017 ◽  
Author(s):  
Andrea Harris
Keyword(s):  
New York ◽  
Twentieth Century ◽  
New York City ◽  
Driving Force ◽  
George Balanchine ◽  
Current State ◽  
The Arts ◽  
History Of ◽  
Lincoln Center

The Conclusion briefly examines the current state of the New York City Ballet under the auspices of industrial billionaire David H. Koch at Lincoln Center. In so doing, it to introduces a series of questions, warranting still more exploration, about the rapid and profound evolution of the structure, funding, and role of the arts in America through the course of the twentieth century. It revisits the historiographical problem that drives Making Ballet American: the narrative that George Balanchine was the sole creative genius who finally created an “American” ballet. In contrast to that hagiography, the Conclusion reiterates the book’s major contribution: illuminating the historical construction of our received idea of American neoclassical ballet within a specific set of social, political, and cultural circumstances. The Conclusion stresses that the history of American neoclassicism must be seen as a complex narrative involving several authors and discourses and crossing national and disciplinary borders: a history in which Balanchine was not the driving force, but rather the outcome.

scholarly journals A Monolithic Approach of Fluid–Structure Interaction by Discrete Mechanics

Fluids ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 95
Author(s):  
Stéphane Vincent ◽  
Jean-Paul Caltagirone
Keyword(s):  
Solid Mechanics ◽  
Mechanical Energy ◽  
Fluid Structure Interaction ◽  
Equation Of Motion ◽  
Discrete Equation ◽  
Discrete Mechanics ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Vector Potentials

The unification of the laws of fluid and solid mechanics is achieved on the basis of the concepts of discrete mechanics and the principles of equivalence and relativity, but also the Helmholtz–Hodge decomposition where a vector is written as the sum of divergence-free and curl-free components. The derived equation of motion translates the conservation of acceleration over a segment, that of the intrinsic acceleration of the material medium and the sum of the accelerations applied to it. The scalar and vector potentials of the acceleration, which are the compression and shear energies, give the discrete equation of motion the role of conservation law for total mechanical energy. Velocity and displacement are obtained using an incremental time process from acceleration. After a description of the main stages of the derivation of the equation of motion, unique for the fluid and the solid, the cases of couplings in simple shear and uniaxial compression of two media, fluid and solid, make it possible to show the role of discrete operators and to find the theoretical results. The application of the formulation is then extended to a classical validation case in fluid–structure interaction.

scholarly journals Horizontal Gene Transfer Involving Chloroplasts

2021 ◽  
Vol 22 (9) ◽  
pp. 4484
Author(s):  
Ewa Filip ◽  
Lidia Skuza
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Driving Force ◽  
Genetic Material ◽  
Adaptive Significance ◽  
Chloroplast Genomes ◽  
Organelle Genomes ◽  
Number Of Genes ◽  
Cellular Compartments

Horizontal gene transfer (HGT)- is defined as the acquisition of genetic material from another organism. However, recent findings indicate a possible role of HGT in the acquisition of traits with adaptive significance, suggesting that HGT is an important driving force in the evolution of eukaryotes as well as prokaryotes. It has been noted that, in eukaryotes, HGT is more prevalent than originally thought. Mitochondria and chloroplasts lost a large number of genes after their respective endosymbiotic events occurred. Even after this major content loss, organelle genomes still continue to lose their own genes. Many of these are subsequently acquired by intracellular gene transfer from the original plastid. The aim of our review was to elucidate the role of chloroplasts in the transfer of genes. This review also explores gene transfer involving mitochondrial and nuclear genomes, though recent studies indicate that chloroplast genomes are far more active in HGT as compared to these other two DNA-containing cellular compartments.

Topography of the Free Energy Landscape on the Claisen-Schmidt Condensation: Solvent and Temperature Effect in the Rate-Controlling Step

2021 ◽  
Author(s):  
Nayara Dantas Coutinho ◽  
Hugo Gontijo Machado ◽  
Valter Henrique Carvalho-Silva ◽  
Wender A. Silva
Keyword(s):  
Free Energy ◽  
Temperature Effect ◽  
Strong Influence ◽  
Aldol Condensation ◽  
Energy Landscape ◽  
Bond Formation ◽  
Free Energy Landscape ◽  
Rate Controlling Step ◽  
Formation Step

Recent studies have assigned hydroxide elimination and C=C bond formation step in base-promoted aldol condensation the role of having a strong influence in the overall rate reaction, in contrast to...

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