The article discusses the formulation of the problem of multicriteria design of a robotic system consisting of a group of robots, with the aim of achieving specified targets. A new approach to organizing the control o...
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The article is devoted to the problem of computer modeling of rational design of tracked vehicle transmissions with multiple criteria. The problems of finding optimal geometric parameters that satisfy several quality ...
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The chapter contains a brief description of chapters that contribute to the development and applications of computational methods and algorithms in different areas of gas, fluid, and plasma dynamics, solid mechanics, ...
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The new version of the software system DASS designed to solve multicriteria problems using methods of the criteria importance theory is described. A new approach has been developed by the authors, allowing to take int...
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Due to the scaling down of CMOS and MEMS technology, the variation of capacitance decreases to the sub-femto-farad level. The signal charge from sensing element is weak, it is vulnerable to the dynamic coupling interf...
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Due to the scaling down of CMOS and MEMS technology, the variation of capacitance decreases to the sub-femto-farad level. The signal charge from sensing element is weak, it is vulnerable to the dynamic coupling interference. This interference generates error charge that significantly affects accuracy of signal transmission. It is a crucial problem that how to assure the signal integrity (SI) for such a high-precision readout circuit. This paper deals with SI and EMI analysis of MEMS capacitive sensor-accelerometer/inertial sensor. And the paper demonstrates how significantly the IC-layout can contribute to the EMC performance of sub-femto-farad readout circuit for MEMS capacitive sensor. The measurement results show that the precision IC-layout reduces the equivalent input offset and improve the EMC performance of the readout circuit.
The process of uniform supernovae explosions (SNe) is well investigated for all their types. However, observational data suggests that the SNe could be not spherically-symmetric. Modern multidimensional simulations of...
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The processes of fatigue crack propagation in titanium compressor and fan disks of contemporary gas-turbine engines are generalized. As it was shown, the cracks in a disk material can initiate and propagate at the mic...
The processes of fatigue crack propagation in titanium compressor and fan disks of contemporary gas-turbine engines are generalized. As it was shown, the cracks in a disk material can initiate and propagate at the micro-, meso- and macroscale level depending on the crack origination location, namely, rim or hub part of disks. Crack growth mechanisms are determined by the dominant mechanism of wave process of plastic deformation for titanium alloys, which appears during forging of compressor and fan disks. This process results in creation of filament-type structure with alternating brittle and ductile filaments of two-phase titanium alloys. The features of titanium alloy fracture in the regions of high-cycle and very-high-cycle fatigue are considered. The instances of in-service failure for fan and compressor disk from titanium alloys are demonstrated, and both the duration of fatigue crack growth, and equivalent stress level are estimated.
Modern VHCF testing regimes are studied. A new loading scheme applicable to a piezoelectric fatigue testing machine is proposed. The scheme is studied analytically and numerically. The analytical part comprises the ca...
Modern VHCF testing regimes are studied. A new loading scheme applicable to a piezoelectric fatigue testing machine is proposed. The scheme is studied analytically and numerically. The analytical part comprises the calculation of the specimen's geometry to operate correctly on the VHCF testing machine, as well as the specimen's stress-strain state calculation during an experiment in order to determine the one's durability. A model based on a kinetic damage equation is introduced. This model is used in the numerical experiment. The behavior of a finite-element specimen in a fatigue experiment is calculated from the beginning up to the stage of active crack growth.
The problem of cyclic loading under pure torsion is an important problem for numerous different industrial applications, such as shafts, springs, blades, and others. The loading conditions for aircraft, railway, autom...
The problem of cyclic loading under pure torsion is an important problem for numerous different industrial applications, such as shafts, springs, blades, and others. The loading conditions for aircraft, railway, automobile industries are often corresponding to long fatigue life. The rough estimation shows that the number of cycles for springs in car engine is exceeds 108 cycle while blades for aircraft turbine may undergo more than 1010 loading cycles. Such, to provide a safety in service life for such elements a multiaxial fatigue failure criterion is needed to predict damage zone location and fatigue life. This paper is aimed to introduce the multi regime approach to predict fatigue damage zone evaluation and number of cycles to crack initiation and total fatigue life. The presented approach is based on damage theory supplemented by multiaxial failure criterion. The proposed model includes the algorithm for automatic determination the fatigue loading range (low-, high- or very-high cycle fatigue) and allows different crack opening modes. To show how to apply the proposed approach and verify the results of calculation the series of numerical simulation on hourglass specimen subjected to VHCF pure torsion is performed. The results of numerical simulation are compared to VHCF torsion tests.
This article discusses the vulnerabilities and complexity of designing secure IoT-solutions, and then presents proven approaches to protecting devices and gateways. Specifically, security mechanisms such as device aut...
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