Performance of flexible retaining walls supporting dry cohesionless soils under cyclic loads     

Raj Siddharthan  Emmanuel M. Maragakis 《国际地质力学数值与分析法杂志》1989,13(3):309-326

A finite element model is proposed for studying the seismic response of a flexible retaining wall/soil system. The model accounts for nonlinear hysteretic soil behaviour, and also for the increase in lateral stresses and settlement related to grain slip caused by cyclic loads. The response computed by the proposed method was compared with responses recorded at the Cambridge centrifuge facility, and found to be in reasonable agreement. The model was then used to identify the importance of factors such as flexibility of the wall and relative density of the backfill. The study reveals that the maximum bending moments given by current design procedures are nonconservative for stiffer walls. Deflections of flexible walls are of major concern. Flexible walls supporting a sand of medium density yield the greatest deflection.  相似文献   

Effect of oblateness on triangular solutions at critical mass     

Ram Krishan Sharma  P. V. Subba Rao 《Astrophysics and Space Science》1979,60(2):247-250

At critical mass the triangular equilibria in the planar restricted three-body problem, when the more massive primary is an oblate spheroid with its equatorial plane coincident with the plane of motion, are in general unstable due to the presence of secular terms in the solutions of linearized equations of motion in the vicinity of these points. Existence of retrograde elliptic periodic orbits is established through suitable velocity components. The eccentricity of these orbits increases with the oblateness.  相似文献   

Discovery of a flare star near Sirius     

D. P. Sharma  T. M. K. Marar  S. Seetha  K. S. Shyla  K. Kasturirangan  U. R. Rao  J. C. Bhattacharyya  M. J. Rozario 《Astrophysics and Space Science》1983,91(2):467-476

The discovery of a flare star (R.A. (1950)=6^h43^m6^s.07, Decl.(1950)=?16°45′24″) located about 6 arc min south of Sirius is reported. During photometric observations on the night of 13 January, 1982, using the 102 cm telescope at Kavalur, India, the star was seen to brighten by 2.55 mag. inV band over a duration of about 200 s. Observations on this object for a duration of about 10.5 hr spread over seven more nights indicate the star to be variable. The results of these observations are presented.  相似文献   

A gravitationally non-degenerate cosmological model with expanding and shearing viscous fluid in general relativity     

Raj Bali  Deepak Raj Jain 《Astrophysics and Space Science》1987,139(1):175-181

The object of this paper is to investigate the behaviour of viscosity in a cosmological model, in which the coefficient of shear viscosity is assumed to be proportional to rate of expansion in the model. The behaviour of the model in the absence of shear viscosity is also discussed.  相似文献   

Gravitational instability of a Hall plasma in the presence of suspended particles     

K. C. Sharma 《Astrophysics and Space Science》1982,85(1-2):263-269

The gravitational instability of an infinite homogeneous and infinitely conducting selfgravitating gas particle medium in the presence of suspended particles of a Hall plasma is considered. The particular cases of the effects of Hall currents and suspended particles on the waves propagated along and perpendicular to magnetic field have been discussed. Jeans's criterion determines the gravitational instability.  相似文献   

Thermosolutal-convective instability in a stellar atmosphere     

R. C. Sharma  Bakshis Singh 《Journal of Astrophysics and Astronomy》1987,8(4):305-314

The thermosolutal-convective instability of a stellar atomsphere is studied in the presence of suspended particles. The criteria for monotonic instability are derived and are found to hold good also in the presence of uniform rotation and uniform magnetic field on the thermosolutal-convective instability. The thermosolutal-convective instability of a stellar atmosphere is also studied in the presence of suspended particles and radiative transfer effects and the criteria for monotonic instability are obtained in terms of source function.  相似文献   

The gravitational instability of flow through porous medium for some systems of astrophysical interest     

R. C. Sharma  K. P. Thakur 《Astrophysics and Space Science》1982,81(1-2):95-102

The gravitational instability of flow through porous medium for some hydrodynamical and hydromagnetical systems of astrophysical interest is investigated. The effects of rotation, magnetic field, viscosity and finite electrical conductivity are studied for the gravitational instability through porous medium. The effect of suspended particles on the instability is also considered. It is found that Jean's criterion remains unchanged in the presence of porosity, viscosity, finite conductivity, rotation, magnetic field and suspended particles in the medium.  相似文献   

A study of the effect of relativity change of mass of the electrons with velocity on the M-R relations for a cold spherical body     

J. P. Sharma 《Astrophysics》1979,15(1):108-113

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Nonlinear electrostatic drift Kelvin-Helmholtz instability     

Avadhesh C. Sharma  Krishna M. Srivastava 《Astrophysics and Space Science》1993,200(1):107-116

Nonlinear analysis of electrostatic drift Kelvin-Helmholtz instability is performed. It is shown that the analysis leads to the propagation of the weakly nonlinear dispersive waves and the nonlinear behaviour is governed by the nonlinear Burger's equation.  相似文献   

Thermal-convective instability of a composite rotating stellar atmosphere in the presence of a variable magnetic field     

R. C. Sharma  Bakshis Singh 《Astrophysics and Space Science》1988,143(2):241-247

The thermal-convective instability of a composite stellar atmosphere is considered in the presence of rotation, variable horizontal magnetic field, and collisional effects. The criteria for monotonic instability are obtained which generalize the criterion derived for thermal-convective instability in the absence of above effects.  相似文献