Failures and Phase Transformations in Solids
Investigation on Failure Mechanisms and Phase Transformations in Solids under Dynamic Loadings
Tech Area / Field
- PHY-SSP/Solid State Physics/Physics
8 Project completed
Senior Project Manager
Svetlova A V
VNIITF, Russia, Chelyabinsk reg., Snezhinsk
- Institute of Continuous Media Mechanics, Russia, Perm reg., Perm
- Direction Générale de l'Armement / Direction des Centres d'Expertise et d'Essais/Centre d'Etudes de Gramat, France, Gramat
Project summaryA great number of theoretical and experimental works have been devoted to investigation and theoretical description of failure mechanisms and phase transitions in solid bodies. However, in view of stormy growth of mathematical simulation capabilities, new ways of studying these difficult phenomena are opening.
The content of this proposal is the development of a physic-mathematical model of the solid body with mesoscopic defects with the aim of description of behavior of plastic and brittle materials in the wide loading range from static to dynamic. The phenomenological base should be the analysis of topological invariants of "solid body with defects" nonlinear system and the realization of fractal approach for prediction of critical stage of transition from damage to crack. The physical basis of the model under development is statistic and thermodynamic description of evolution of defects ensemble and growing of martensite phase. The new model, as an important fragment, will include description of macroscopic response of solid body to the growth of microdefects, damages at various stages of failure, including the process of transition from damage to failure.
Investigations in the context of the project will be devoted to studying the deformation and failure of steel and granite. These materials are chosen as the most representative media of industrial and tectonic materials. Mechanisms of failure of these materials are quite different. In steel the failure is preceded by prolonged phase of plastic deformation, while in granite failure has a brittle character. It means that the model will be applied to the wide range of change of materials properties.
The mathematical model will require the development of new numerical method with optimal dispersive and oscillatory characteristics. Qualitatively the new method is needed for elimination of influence of oscillations of solution and wave dispersion on simulation of failure and phase transitions.
It is widely believed that growth of damage is the consequence of distortion. However, studying of failure of solid bodies under dynamic loadings shows that the important role belongs to dilatation. The new model will allow studying the inpidual roles of dilatation and distortion in formation of cracks and their influence on phase transitions. The principal moment in description of these phenomena is tensor structure of parameters of damage, connected with real defects.
Considerations of phase transitions in steel and granite, as disbalanced transitions, will allow to study the metastability of dense phase, that is very important in dynamically loaded solid bodies due to closeness of typical time loading and time of life of metastable phase.
The execution of work under this project will allow to present scientists and engineers, who dealt before with development of weapons and having skills in creating mass destruction weapons, the possibility of reorientation to peaceful activities.
The following foreign specialists support the proposal:
1. Dr. J. Cagnoux, Research Centre "GRAMAT", France
2. Prof. M. Berveller, Metz University, France
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