Mechanics

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The conformal contact between punches and coated solids with complicated surface profile

Authors: Manzhirov A. V., Kurdina S. P., Kuchumov A. G.

The contact interaction between system of rigid punches and viscoelastic foundations with thin coatings for the cases in which the punches and coating surfaces are conformal (mutually repeating) is studied. Such problems can arise, for example, when the punch immerses into a solidifying coating before its complete solidification. The shapes of punches surfaces could be described by a fast oscillating functions. Basic system of mixed integral equation is obtained.

Theoretical investigation of the deformed graphene nanostructures

Authors: Kirillova I. V., Shunaev V. V.

 The results of the theoretical investigations of properties of the deformed graphene structures are presented in this work. We investigated mechanical properties of the bi-layer graphene structures by means of the molecular dynamics method. To evaluate mechanical properties of graphene we applied a compression load to graphene. As a result of the investigations it was found that graphene became a wave-like with the increase of the compression.

Mechanical properties study for graphene sheets of various size

Authors: Kirillova I. V., Kossovich E. L., Fadeev A. A.

We studied mechanical properties of large graphene sheets. The Young's modulus was found for each of the considered nanoparticles and sheets. To this end, the deformation was applied in two orthogonal directions – zigzag and armchair directions of the graphene atomic framework. It was established that there exist a size effect on the Young's modulus of graphene.

Local effects of the weak thermogravitational convective flows

Authors: Otpushchennikov S. V.

The features of the natural low intensity thermo-gravitational convection occurring in microacceleration condition have been investigated numerically. The effect of thermal boundary conditions on the local characteristics of temperature field has also been studied. It was shown that the value of maximum temperature stratification depends monotonically on the intensity of heat transfer at the system boundaries.

About a problem of spacecraft's orbit optimal reorientation

Authors: Pankratov I. A., Sapunkov Y. G., Chelnokov Y. N.

 The problem of optimal reorientation of the spacecraft's orbit is solved with the help of the Pontryagin maximum principle and quaternion equations. Control (thrust vector, orthogonal to the orbital plane) is limited in magnitude. Functional, which determines a quality of control process is weighted sum of time and module (or square) of control. We have formulated a differential boundary problems of reorientation of spacecraft's orbit.

Research of consequences of tether's jamming in the task of payload delivery from an orbit

Authors: Ledkov A. S., Dyukov D. I.

In article the off-normal situation of tether's jamming at the decision of the task of payload delivery from an orbit by means of a tether is considered. The mathematical model described the space tether system consisting of the basic space vehicle, the tether and the payload is used. At creation of model the mass and damping properties of the tether weren't considered. It is supposed that basic space vehicle moves on a circle orbit.

Thermomechanical orthogonality in nonlinear type-III thermoelasticity (GNIII)

Authors: Kovalev V. A., Radaev Y. N.

The present paper is devoted to formulations of constitutive equations for the non-linear Green–Naghdi type-III thermoelastic continuum consistent with the principle of thermodynamic (or thermomechanical) orthogonality.

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