


Том 36, № 1 (2016)
- Жылы: 2016
- Мақалалар: 18
- URL: https://journal-vniispk.ru/1068-798X/issue/view/13909
Article
Models of the turn resistance for high-speed caterpillar vehicles
Аннотация
Experimental results for the drag torque on a high-speed caterpillar vehicle entering a turn are compared with the drag torques determined by existing methods for steady curvilinear motion. Nikitin’s model proves applicable not only for steady turns but also as the trajectory changes on entering a turn.















Generation of a random vector field with a specified coherence matrix in vibrational tests
Аннотация
Methods that are easily implemented on a computer are proposed for generating two correlated random processes of the same duration with specified coherence function and generating random signals with a specified spectral matrix of any size.



Predicting the elastic properties of randomly reinforced polymer composites with antifrictional additives
Аннотация
The elastic properties of composites (the Young’s modulus, Poisson’s ratio, Lame constant, and shear elastic modulus) are determined in model calculations, when the variation in concentration of the components is taken into account.









Concentration gradients in the surface layer of titanium alloy ground by a silicon-carbide wheel
Аннотация
The concentration gradients of alloying elements and impurities in surface nanolayers of BEZ-1 titanium alloy after grinding by a silicon-carbide wheel are determined. The concentrations are determined by local X-ray spectral microanalysis.



Plasma–powder application of antifrictional babbitt coatings modified by carbon nanotubes
Аннотация
Modification of Babbitt coatings by carbon nanotubes in plasma–powder application is considered. A model is proposed for the interaction of a graphene-like surface and atoms from the Babbitt alloy. The influence of carbon nanotubes obtained by different means on the performance of antifrictional coatings is studied.






Resistance of titanium alloys to cutting
Аннотация
A thermomechanical model of the resistance of titanium alloys to cutting is proposed. The model takes account of the influence of the strain, strain rate, and temperature on the yield point. The maximum yield point in the chip-formation zone and at the front surface of the cutter is established. Analysis of elementary-chip formation in the turning of titanium alloys permits the determination of the temperature and cutting force.



Wheel–workpiece interaction in peripheral surface grinding
Аннотация
A model of the wheel–workpiece interaction in peripheral surface grinding is developed. The goal is to predict the microrelief of the blank after repeated microcutting. Models of the abrasive grain, the grinding wheel, individual scratches, and the three-dimensional microrelief of the blank are presented. Experimental results confirm the validity of the model.



Abrasive-tool wear and the machinability of high-speed tungsten-free steels
Аннотация
The physics of grinding is considered in order to explain the difference in machinability of tungstenfree and tungsten steels. The strength of the most common steels and alloys is studied over a broad range of strain rate and temperature. Analysis of the results established the variation in strength of high-speed tungsten-free and tungsten steels in typical grinding conditions and permits explanation of the difference in machinability of the steels in physical terms. The relation between the machinability of steel and wear of the abrasive tool is investigated in experiments with individual grains (plane angle ϕ = 90°) of different abrasive materials: electrocorundum (24A), zirconium corundum (38A), and Elbor (Borazon). That permits the derivation of a regression equation reflecting the qualitative characteristics of the process, such as the starting point, the presence of an extremum, and the asymptotic behavior.



Prediction of the cooling of cutting zones by means of vortex tubes in high-speed machining
Аннотация
The possibility of using vortex tubes to inject cooled ionized air into the cutting zone in high-speed machining is considered. Numerical calculation of the vortex effect is employed to predict the cooling of the cutting zone. The results are compared with experimental data.



Automated manufacture of compressor-blade tailpieces
Аннотация
An effective method of machining the geometrically complex surfaces of compressor blades in gas-turbine engines is considered (creep-feed grinding). This method is widely used in the machining of hard materials such as high-temperature nickel alloys and cobalt alloys employed in the manufacture of gas-turbine components.



Diagnostics of drilling in numerically controlled machine tools
Аннотация
Cutting-tool vibration is considered on the basis of existing physical notions regarding forced, free, and self-exciting vibration in a cutting system that consists of interacting tool and workpiece subsystems. A vibrodiagnostic system is studied experimentally in the drilling of a small-diameter by means of an NI CompactDAQ measuring complex.


