The paper presents the results of experimental researches of the basic working capacity characteristics of pulsed variable-speed drives – gear ratio, efficiency factor and reliability of the eccentric free-wheel mechanisms When conducting research, the main working capacity parameters of the pulsed variable-speed drive (independent factors) changed according to the design of experiment in the range: the load applied to the output shaft was from 250 to 2.750 N·m; adjustable gear ratio – from 20 to 180. It was established that the reliability of the eccentric free-wheel mechanisms is guaranteed when making mechanisms of 100Cr6 steel with hardness not lower than HRCЭ 58…62 with a module of at least 0.75 mm. It was shown that the yield surface, which characterizes the change in the gear ratio of the pulsed variable-speed drive, can be described by a model using first-order polynomials. It was established that with increasing load, a slight increase (at 1.0…9.9%) occurs in the adjusted gear ratio, which has a character close to linear. It was concluded that with an increase in load, the increase in efficiency factor is non-linear and equals 1.8…2.6 times, an increase in the gear ratio causes its linear decrease by 1.13…1.64 times in the dependence close to a linear one. Empirical dependences are obtained to determine the magnitude of the gear ratio and efficiency factor.
Machines. Technologies. Materials.
Vol. 13 (2019), Issue 4
Table of Contents
The modeling of energy transfer systems in ultrasonic technological machines is considered. As such systems rod waveguides are usually used. These are, as a rule, distributed systems of variable cross-section, which must transmit energy from an electromechanical vibration exciter to a working body. Sometimes additional equipment is attached to the waveguide (core system), which should be modeled using lumped-parameter subsystems. This article discusses the problems related to the modeling and calculation of the so-called ultrasonic concentrators – waveguides that have a heterogeneous shape and are made to ensure optimal energy delivery to the working body (instrument). Examples of calculations are given that consider the influence of a nonlinear elastic-dissipative load, determined by the nature of the technological process. The analysis of real models is described.
PROGRESS IN THE DEVELOPMENT OF THE CUTTING ASSEMBLIES’ CONSTRUCTION OF WORKING MACHINES DUE TO THE REDUCTION IN POWER CONSUMPTIONpg(s) 155-157
New construction of the cutting assembly developed at the Institute of Mechatronics and Working Machines of the University of Technology and Life Sciences in Bydgoszcz. That new construction is covered by the patent protection. The conducted and presented results of the experimental tests have shown, that it is characterised by lower power consumption as compared to the classical construction, which is commonly used in working machines.
In this article the authors quoted results of traction motors speed performance variations statistical analysis and wage wheels bands diameters deviations according to operation data. The authors of this publication offered the method of determining the nonuniformities of current distribution in the power circuit of the locomotive, based on probabilistic approach, and also performed its comparison with classic computation approach. The next statistical performance of the continuous current locomotives traction drive is as follows: mathematical expectation of the motors magnetic flux; mean square deviation of magnetic flux; statistical dispersion and average square deviation of wage wheels bands diameters. With help of the received data it became possible to improve determination of nonuniformities currents deviations on traction motors during loading of the electric locomotives.
This paper presents an exergy analysis of wet cooling tower at three different loads and in a range of the ambient temperatures.
Increase in cooling tower load increases its exergy destruction and simultaneously decreases cooling tower exergy efficiency, while an
increase in the ambient temperature causes a decrease in cooling tower exergy destruction and simultaneously decreases its exergy
efficiency. The lowest cooling tower exergy destructions (between 1417.54 kW and 2925.65 kW) are obtained at low load. The highest
cooling tower exergy efficiencies are calculated at the lowest observed ambient temperature of 5 °C – they amount 64.31 % at low load,
54.80 % at middle load and 53.94 % at high load. The change in ambient temperature for 5 °C resulted with a change in cooling tower
exergy efficiency of 4 % or more on average.
The object of the research is waste polyethylene, polypropylene, polyethyleneterephthalate and polyvinylchloride, which are subjected to pyrolysis utilization with plant raw materials as a carrier. The purpose of the study is the thermal processing of these wastes into carbon adsorbents and the analysis of their adsorption properties. Combinations of the most spread polymeric wastes and plant raw materials, as well as products of its transformation (wood, peat, lignite, coal and its coke) were studied as feedstocks for the production of carbon adsorbents. The temperature regime of pyrolysis of plant materials was determined according to the results of thermographic analysis. The effect of the type of raw materials and polymeric wastes on the yield and on the parameters of porous structure of the produced adsorbents was estimated and the high-quality samples among them were selected.
The paper contains the results of the study on the systematization and formalization of specialized approaches to planning supply chains of leading metal companies and comparison of these practices with the standard supply chain management models SCOR & CCOR & DCOR and GSCF. The paper defines the main directions of development of the methodology of supply chain planning in terms of its adaptation to the specifics of metals.
The main objective of this paper is to develop and calibrate traffic synthetic model for forecasting traffic demand in Anamorava region. The model on existing situation is developed based on “meta model” which uses PTV Visum software. In order to set up a model were taken into account input variables number of residents, number of people employed, working places available as well as the traffic volume entering and exiting this region at “peak hour”. With intention to have traffic volumes as an outcome expressed as AADT, correction coefficients are applied. Multiplying the traffic volumes with correction coefficient there is traffic demand gained for the period of 24 hours which is an indicator to be used for comparison of results. In order to get the reliable model for forecasting, calibration of it is done through TFlow Fuzzy algorithm technique based on GEH test, R2 and percentage deviation criterions. Once the level is completed satisfactory, the final model can be used to forecast the traffic demand for this region.
RESEARCH INTO THE EFFECT OF CERTAIN CHEMICAL ELEMENTS IN MICROALLOYED STEEL GRADES ON CONCAST SLAB AND ROLLED PLATE SURFACE QUALITYpg(s) 178-182
Investigators has developed a complex technology of manufacture of high quality skelp and shipbuilding grades and nickel-,chromium-, molybdenum-, niobium- and vanadium- microalloyed steels with carbon mass fraction within 0.06% to 0.22% and manganese mass fraction within 1.0% to 1.7%. Over the course of the research, relative occurrence of surface cracks of various morphology – transverse, longitudinal, spider, net-like – on the concast slab surface has been determined. The above research resulted in the development of a number of technological innovations both in preparation of liquid steel for casting and in continuous casting itself, preventing initiation or reducing by 30% – 40% the amount of surface defects on the rolled plates.
The evaluation of ductile cast iron is common foundry practice. For the correct non-destructive evaluation (NDE) of mechanical properties (ultimate tensile strength; relative lengthening; Brinell’s hardness; elasticity modulus) by means ultrasonic testing and inverse regression analysis are used.
THE INFLUENCE OF NATURAL AGING AND PRE-AGING ON THE MECHANICAL, PHYSICAL AND MICROSTRUCTURAL PROPERTIES OF THE EN AW-6060 ALUMINUM ALLOYpg(s) 187-189
The aim of this paper is the investigation of the effect of natural aging on the mechanical, physical and microstructural properties of an EN AW-6060 aluminum alloy. These properties were investigated during different aging treatments. Firstly, the effect of natural aging on properties was investigated, after which the influence of natural aging (room temperature pre-aging) on the artificial aging was studied. The results showed the beneficial effect of natural aging in both sets of experiment. During the natural aging, the hardness increased for around 20 % while electrical conductivity values were slightly higher than in the quenched sample. The hardness of the samples gradually increases up to 25 days of natural aging reaching a plateau state, after which the values of hardness remain the same. Also, room temperature pre-aging had a positive effect on subsequent artificial aging. Samples that were pre-aged for 40 days or more before artificial aging had around a 13 % increase in hardness values compared to the samples that were directly artificially aged. Electrical conductivity had increased by around 1 MS/m in pre-aged samples compared to only artificially aged samples. Optical microscopy investigations confirmed the existence of precipitated phases and their distribution in the microstructure.
The base process was obtained: 3D hardening temperature field for the K-test under heat transfer at conditions with maximum intensity. A methodology for determining macro-level defects in aluminum alloys. It is definitely the placement of the K-test method in the process of creating the first order phase transition in a casting technology. The idea of interaction between the classical theory of crystallization and quantum mechanics for the processes of structure formation at casting was introduced by Stefan’s task in volume with nano-size.
It was analyzed the methods of constructions the matter with maximal of packing coefficient when the objects consist of the particles with forms either spheres or rods or plates. It was calculated the relations the partial size for relating of maximal packing coefficient. As examples of objects with coefficient of packing theirs particles we look on abrasive materials and products of the powder metallurgy and solid fuel etc.