排序方式： 共有24条查询结果，搜索用时 34 毫秒
1.
We consider the advantages of a formalism based on concept of the asymmetric continuum and we present some equivalence theorems
relating it to the asymmetric elasticity and to micropolar and micromorphic theories as founded by Nowacki, Cosserats and
Eringen.
We consider the basic processes in an asymmetric continuum which could be reduced to the point basic motions/deformations.
The co-action of spin and shear motions is assumed to play the main role in fracturing process, while the constitutive relation
between the antisymmetric stresses and rotations replaces the friction constitutive law. 相似文献
2.
R. Teisseyre 《地学学报》1992,4(4):509-513
The principles and assumptions of the Earthquake Premonitory and Rebound Theory are reviewed. The Theory based on a continuum model of fracturing processes; the stress evolution equations describe the dynamic processes governing a continuous distribution of dislocations.
Special attention is paid to the problem of electric current generation in a seismic source zone. Electric current is considered as reflecting the rate of polarization, which is influenced by motion of the charge-bearing dislocations; the relationship between the current density and stress accumulation rate is derived. 相似文献
Special attention is paid to the problem of electric current generation in a seismic source zone. Electric current is considered as reflecting the rate of polarization, which is influenced by motion of the charge-bearing dislocations; the relationship between the current density and stress accumulation rate is derived. 相似文献
3.
Roman Teisseyre 《Journal of Seismology》2012,16(4):683-694
Asymmetric continuum theory points to the equal roles of the rotation motions and those related directly to shear or confining strains. The strain motions could be quite independent or mutually related with the eventual phase shifts, while the displacements have only a mathematical sense; a real displacement may appear along the fracture slip only. Formally, any deformation could be presented as related to the displacements; however, its origin in a fracture source should be considered either as belonging to an individual process or to complex correlated events; in these cases, the confining, shear and rotation strains can be related mathematically to the different displacement fields. Some of these related deformations could be emitted from a source with a phase shift, while the observed displacements (deduced from records) result as a sum of these independent displacements. An important influence on a source process and on the premonitory micro-events has the material defects, their distribution, and mobility. The defect arrays lead to a concentration of stresses and their local reorganization. Thus, in this paper, we consider the induced stresses and strains related to defect content and to its modification and redistribution. Moreover, an important role in understanding the complex correlated events in a source plays the release?Crebound mechanism. The release?Crebound mechanism in an earthquake source processes leads to a possible direct or phase-shifted correlations between the emitted motions; in this aspect, a propagation of the coupled strain and rotation waves is discussed. In particular, we consider the point fracture events as related either to a confining load or/and to the shear and rotation processes; we discuss the related effects and their meaning when discussing the fault plane mechanism and emitted waves. In some important seismic regions, we have the recording system which permits to record the strains and rotations. However, we should point that the wordwide seismological network is not adequate to record the complex strain deformations released in the fracture processes and remains quite insufficient to understand the global stress changes and related strain waves of a very low period. Consideration on a recording mechanism of the long displacement waves indicates the insufficiencies of the present global recording system and points that recording of the global strain and rotation waves is an important and urgent task. 相似文献
4.
Roman Teisseyre 《Acta Geophysica》2013,61(1):18-25
The Asymmetric Continuum Theory based on deformation fields includes the strain rotation as an equally important deformation part as the shear and confining strains; all these fields can be related to their origin in the fracture processes by some displacement motions in a source. Some of these motions may belong to an individual process, some to complex correlated events; in this latter case the displacements related to these strains could be shifted in phase. Moreover, we may expect an appearance of some molecular transport motions; the molecular transport may be helpful for understanding an interaction of the molecular processes and related molecular momentum flux. These correlated events should be mutually related in a source by the release-rebound mechanism. In particular, we consider the point fracture events as associated with a confining load or/and with the shear and rotation processes; we discuss the related effects and their meaning when discussing the fault plane mechanism and emitted waves. It is to be pointed out that such molecular motions are too small to be observed by the existing seismological networks. 相似文献
5.
We present a new development in the asymmetric continuum theory with the shear oscillations (twist motions) and independent
spin; these motions (displacement velocities and spin) can be shifted in phase to describe the independent rebound processes.
Our approach provides an extension of the asymmetric continuum theory by including the microfragmentation processes with a
double transport which may appear in an advanced fracture process under very high load. The related nonlinear equations, leading
to soliton solutions, are derived. 相似文献
6.
Summary A theoretical model of an electroelastic continuum has been applied in this paper to the problem of electrodynamic phenomena (piezoelectricity, electrostriction, etc.) associated with earthquakes. In such a model the coupling between electric and mechanical fields expresses itself by a change of scale of mechanical effects along the electric field, as well as by the additional electric charge created by the earthquake source.The electrokinetic phenomena associated with earthquakes and caused by the diffusion of fluids into the dilatant region have been considered using the theory of porous media with interstitial fluid flow. General relations describing electrokinetic effects caused by the deformation processes in an earthquake source have been obtained. 相似文献
7.
8.
Krzysztof P. Teisseyre 《Acta Geophysica》2007,55(4):535-553
Analysis of a group of seismic events which took place in central Italy and have been recorded at the l’Aquila Observatory
reveals proportionality between the maximum seismic signal (the displacement velocity) and the maximum amplitudes of rotational
components. To compare the seismic events in the aspect of energy emitted as rotational motions, the rotation indices are
used; these indices help us also to differentiate between the results obtained for different frequency spectra.
In the adopted higher frequency range, 2.6–43 Hz, the relation between maximum displacement velocities and the rotation indices
is roughly reciprocal, while for the lower frequencies, 0.3–3 Hz, there is no clear relationship.
The share of rotation motions in the whole seismic energy emitted from the source varies during the seismic event. Research
on the rotational components hidden in the seismic field gives a new insight into the processes in the source. 相似文献
9.
Basing on the Asymmetric Continuum Theory, we develop the thermodynamics including fragmentation spin fracture processes; applications for the earthquake source processes are considered. The fracture band model is used to describe a dislocation and disclination superlattice. The Gibbs free energy of defect formation is specified. A dynamic spin fracture criterion was formulated. Consequently, a dynamic model of rock fracture employing dislocations, disclinations, and cracks was constructed to describe slip and fragmentation fracture processes in the earthquake sources. 相似文献
10.
We follow our former considerations on rotational processes and emission of rotation and shear-twist waves as occurring in
earthquake source zones. A concise presentation of the motion and constitutive relations is given for each type of the four
fundamental point deformations: displacements, rotations, point stretch/squeeze, and string-string point deformations (shear
nuclei). 相似文献