Development of a design methodology for heat-loaded dimensionally stable elements of carbon plastic construction for a remote sensing of the Earth space equipment

One of the most important tasks of the Federal Space Program of Russia for the period until 2025 is the creation of spacecraft for remote sensing of the Earth. An integral part of the design of this class spacecraft is the determination of the parameters of the orbits that are most effective from the standpoint of information content, energy supply and the duration of active existence. In orbital flight, the temperature state of spacecraft in a complex way varies in time and space. The inhomogeneous temperature field of the structural elements of spacecraft can cause shape distortion, which adversely affects the performance of targets. A technique for a comprehensive analysis and determination of the platform composite design parameters, which is part of the spacecraft for remote sensing of the Earth is proposed. The conditions of thermal loading for flight in a sun-synchronous orbit are considered and mathematical modeling of the operating conditions that ensure the effective operation of such spacecraft is performed. The results of modeling the thermal regime of options for composite platform designs are presented. The technique will be useful in determining the complex of orbital characteristics of the Earth remote sensing satellite at the stage of technical proposals.

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INCREASING THE RESOURCE OF DIESEL CYLINDER HEADS BY IMPROVING THE TECHNOLOGY OF THEIR RESTORATION

SCIENTIFIC LIFE ◽

10.35679/1991-9476-2020-15-7-950-957 ◽

2020 ◽

Vol 15 (7) ◽

pp. 950-957

Author(s):

G.D. Mezhetskiy ◽

◽

V.A. Strelnikov ◽

Keyword(s):

Diesel Engines ◽

Thermal Loading ◽

Theoretical Calculations ◽

Operating Conditions ◽

Advanced Technology ◽

Temperature Fields ◽

Cylinder Block ◽

Diesel Cylinder ◽

Thermal Intensity

The article presents the results of studies of the thermal fatigue strength of diesel cylinder heads and their resource under operating conditions, by using the most advanced technology for their restoration. Based on the results of theoretical calculations of durability and operational studies, a restoration technology has been proposed, which makes it possible to increase the resource of cylinder heads by 2 ÷ 2.5 times. For this purpose, the non-uniformity of the temperature field on the firing bottom of the cylinder heads of YaMZ-238NB diesel engines was theoretically determined and experimentally confirmed. On the basis of theoretical calculations, the most heatstressed sections of the plane of the cylinder heads of diesel engines bonded to the cylinder block were determined, and the appearance of cracks in them. When developing a method for calculating the temperature fields of the fire bottom, the universal finite element method (FEM) was used. This method makes it possible to take into account the geometry and conditions of thermal loading of the cylinder heads quite accurately. For the determination of temperature fields, a well-founded assignment of the boundary conditions is crucial. With this in mind, a number of surfaces were determined that characterize the durability of the entire part during operation. As a result of calculations carried out on a computer, temperature fields have been obtained that make it possible to analyze the distribution of temperatures and temperature gradients at any point of the fire bottom. The highest temperatures (620...635K) are localized in the central part of the fire bottom, which is two times higher in thermal intensity than the peripheral one and confirms the appearance of cracks in these places during the operation of diesel cylinder heads.

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Automatic image referencing in satellite surveying

10.33920/sel-4-2106-08 ◽

2021 ◽

pp. 458-463

Author(s):

V.A. Pantyushin ◽

A.A. Andreev

Keyword(s):

Remote Sensing ◽

Topographic Maps ◽

Automatic Determination ◽

Digital Maps ◽

The Earth ◽

Areal Coverage ◽

Fully Automatic

The method of coordinate referencing of remote sensing materials in the process of satellite surveying is proposed in this paper. The method provides automatic determination of position of the survey routes and images in the routes on the surface of the Earth ellipsoid with their subsequent displaying on the nomenclature sheets of topographic maps on the composite table. The method provides for fully automatic development of a scheme of areal coverage with survey materials in the presence of data on the coordinates of photographing points obtained at the moments of exposure. The algorithm can be used to link images to the corresponding areas of electronic and digital maps.

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A Computationally Efficient Multidiode Model for Optimizing the Front Grid of Multijunction Solar Cells under Concentration

Journal of Renewable Energy ◽

10.1155/2020/1907530 ◽

2020 ◽

Vol 2020 ◽

pp. 1-10

Author(s):

Chris H. van de Stadt ◽

Pilar Espinet Gonzalez ◽

Harry A. Atwater ◽

Rebecca Saive

Keyword(s):

Solar Cells ◽

Operating Conditions ◽

Design Parameters ◽

Computationally Efficient ◽

Fast Determination ◽

Wide Range ◽

Multijunction Solar Cells ◽

Efficiency Increase ◽

Light Concentration

We have developed a computationally efficient simulation model for the optimization of redirecting electrical front contacts for multijunction solar cells under concentration, and we present its validation by comparison with experimental literature results. The model allows for fast determination of the maximum achievable efficiency under a wide range of operating conditions and design parameters such as the contact finger redirecting capability, period and width of the fingers, the light concentration, and the metal and emitter sheet resistivity. At the example of a state-of-the-art four-junction concentrator solar cell, we apply our model to determine ideal operating conditions for front contacts with different light redirection capabilities. We find a 7% relative efficiency increase when enhancing the redirecting capabilities from 0% to 100%.

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Parametric Optimization of Structures Under Combined Base Motion Direct Forces and Static Loading

Journal of Vibration and Acoustics ◽

10.1115/1.1424888 ◽

1998 ◽

Vol 124 (1) ◽

pp. 132-140 ◽

Cited By ~ 7

Author(s):

Izhak Bucher

Keyword(s):

Degrees Of Freedom ◽

Structural Parameters ◽

Operating Conditions ◽

Design Parameters ◽

Power Spectral ◽

Loading Patterns ◽

The Cost ◽

Selection Of ◽

Eigenvectors And Eigenvalues

This paper deals with the optimization of vibrating structures as a mean for minimizing unwanted vibration. Presented in this work is a method for automatic determination of a set of preselected design parameters affecting the geometrical layout or shape of the structure. The parameters are selected to minimize the dynamic response to external forcing or base motion. The presented method adjusts the structural parameters by solving an optimization problem in which the constraints are dictated by engineering considerations. Several constraints are defined so that the static deflection, the stress levels and the total weight of the structure are kept within bounds. The dynamic loading acting upon the structure is described in this work by its power spectral density, with this representation the structure can be tailored to specific operating conditions. The uncertain nature of the excitation is overcome by combining all possible spectra into one PSD encompassing all possible loading patterns. An important feature of the presented method is its numerical efficiency. This feature is essential for any reasonably sized problem as such problems are usually described by thousands of degrees of freedom arising from a finite-element idealization of the structure. In this paper, efficient, closed form expressions, for the cost function and its gradients are derived. Those are computed with a partial set of eigenvectors and eigenvalues thus increasing the efficiency further. Several numerical examples are presented where both shape optimization and the selection of discrete components are illustrated.

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The equation of the oscillatory motion of the blade of the earth-moving machine depending on the properties of the ground and the parameters of the blade

E3S Web of Conferences ◽

10.1051/e3sconf/202127411008 ◽

2021 ◽

Vol 274 ◽

pp. 11008

Author(s):

Minsur Zemdikhanov ◽

Rustem Sakhapov ◽

Ramil Gainutdinov

Keyword(s):

Optimal Design ◽

Oscillatory Motion ◽

Design Parameters ◽

Technological Properties ◽

Optimal Parameters ◽

The Earth ◽

Oscillatory Movement ◽

Working Bodies

The influence of the design parameters and technological properties of the ground on the nature of the oscillatory movement of the blade of the working body of the earth-moving machine is investigated. The purpose of the study is to identify the force factors of the interaction of the oscillatory working body of the earth-moving machine with the ground and determine its optimal parameters. The equation of the oscillatory motion of the blade of the working body of the earthmoving machine depending on its design parameters and technological properties of the ground is obtained. The results can be used in the development and determination of the optimal design parameters of the working bodies of earth-moving machines.

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Algorithm for maintaining the energy balance of the power supply system of the earth remote sensing spacecraft under critical operating conditions

Information-measuring and Control Systems ◽

10.18127/j20700814-202103-02 ◽

2021 ◽

Author(s):

G.B. Steganov ◽

Yu.A. Chudnovsky ◽

N.I. Alimov ◽

A.A. Skoptsov

Keyword(s):

Remote Sensing ◽

Energy Balance ◽

Power Supply ◽

Power Supply System ◽

Supply System ◽

Operating Conditions ◽

Rechargeable Battery ◽

Earth Remote Sensing ◽

Storage Devices ◽

The Earth

In this paper, we consider the problem of maintaining the energy balance of the power supply system of the Earth remote sensing spacecraft in critical operating conditions with the most intense cyclogram of the spacecraft operation, the maximum state of degradation of energy sources and storage devices, as well as with the minimum time to replenish useful energy.The problem of maintaining balance is formulated as a problem of nonlinear mathematical programming with functional constraints. Goal of the work is improving the efficiency and survivability of the remote sensing spacecraft and maintaining the energy balance of the power system in critical operating conditions by transferring the storage devices of the accumulating subsystem of the spacecraft to a given level of charge in the minimum charge time. An algorithm for controlling the accelerated charge of the rechargeable battery with the analysis of the Nickel-hydrogen battery temperature and its time derivative is developed.in some cases, the rechargeable battery replenishment time was reduced by 12−20%. The proposed algorithm for maintaining the energy balance can be used to select the stages of the accumulating subsystem charge current and transition from the current stage to the next one in a minimum time, providing flexibility in managing the modes of electricity storage with the adaptation of the charging current profiles to changing critical operating conditions.

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Determination of the main design parameters of cost-effective remote sensing satellite systems at the stage of preliminary design

Journal of Physics Conference Series ◽

10.1088/1742-6596/1745/1/012089 ◽

2021 ◽

Vol 1745 (1) ◽

pp. 012089

Author(s):

V V Salmin ◽

V I Kurenkov ◽

S L Safronov ◽

I S Tkachenko ◽

A A Yakischik ◽

...

Keyword(s):

Remote Sensing ◽

Cost Effective ◽

Design Parameters ◽

Preliminary Design ◽

Main Design ◽

Satellite Systems ◽

Remote Sensing Satellite

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Development of a Method for Determining Radiant Heat Transfer for Spacecraft Platforms in Near Earth Orbit Flight

Proceedings of Higher Educational Institutions Маchine Building ◽

10.18698/0536-1044-2021-3-62-70 ◽

2021 ◽

pp. 62-70

Author(s):

K.V. Mikhailovskiy ◽

M.A. Gorodetskiy

Keyword(s):

Thermal Loading ◽

Radiant Heat ◽

Heat Fluxes ◽

Operating Conditions ◽

Outer Side ◽

Earth Orbit ◽

Radiant Heat Transfer ◽

The Sun ◽

Structural Elements ◽

The Earth

External heat fluxes are the main factor affecting spacecraft in near-earth orbits. These fluxes can vary during orbital motion due to the different orientation of the satellite to the Sun. To develop a method for simulating heat fluxes incident on structural elements of the outer surfaces of a spacecraft, taking into account their operating conditions, is an urgent task. The paper introduces a method for a comprehensive analysis of heat fluxes incident on the structural elements of a spacecraft under conditions in near-earth orbit flight. Within the study, we consider direct and reflected from the Earth solar fluxes of thermal radiation, as well as infrared fluxes of radiation from the Earth and "visible" structural elements. To verify the compiled model, we carried out mathematical simulation of the thermal loading of the outer side of the spacecraft platform, located on the illuminated side of the sun-synchronous orbit. The method will be useful when choosing a working orbit in designing a spacecraft at the stage of technical proposals.

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