Machines. Technologies. Materials.
Vol. 15 (2021), Issue 3

Table of Contents

  • MACHINES

    • Determination of resistance to motion during operation of belt conveyor

      pg(s) 86-88

      Belt conveyors play a significant role in the transport of bulk materials due to a number of advantages such as: high capacity, economy, safety and reliability. The belt conveyor for bulk materials was observed in this paper. In order to drive the belt conveyor, the power of the driving electric motor must overcome all the resistances that occur during the transport of materials. The paper presents one of the possible approaches to the method of calculation and selection of belt conveyor parameters. The conveyor travel path was adopted, all resistances to the motion of the belt and materials were defined and the calculation of the total resistance to motion on characteristic transport sections was performed. The influence of conveyor loading and discharge devices, drive mechanism, way of moving the belt over the rollers were taken into account. The general calculation algorithm is presented and a graphical representation of the con veyor assemblies is given for the defined transport route.

    • Determining stress intensity factors of mode I for the crack in rectangular cross-section of thin-walled beam

      pg(s) 89-92

      A fracture mechanical behavior of thin-walled elements with through-thickness crack is researched. General analytical methods to determine stress intensity factors (SIF) in such elements are presented. The methods are based on the assessments of nominal stresses in the process of crack growth (first method) and change of inertia moment in defective section (second method). Correction functions are obtained for the central crack under bending for rectangular cross-section of thin-walled beams

    • Development of mechanism and machine mechanics in Belarus and interaction with Bulgarian scientific and engineering centers and associations Part 1. Gear drives and power transmissions

      pg(s) 93-98

      Main directions and trends of mechanism and machine mechanics developing in Belarus are considered. Results of investigations fulfilled in the Joint Institute of Mechanical Engineering and V.A. Bely Metal Polymer Research Institute of NASB, Belarusian National Technical and Belarusian-Russian Universities, as well as in Belarusian State Transport University and other Belarusian research centers are presented. Generally, these investigations are forwarded for modernization of drives of various machines and mechanisms, including mobile machines, instrument mechanisms and estimation of their operation characteristics in the frame of “Industry 4.0” conception. The paper is divided into two parts. The first part focuses on gears and powertrains. Parts of the paper contain sources of information and main publications of Belarusian scientists. Thus, the paper as a whole bears informational and bibliographic character

    • Walking pattern generation and control for a bipedal robot

      pg(s) 99-102

      Bipedal, four-legged and humanoid robots are rapidly increasing in our lives. The design and development of robots continue in similar. For this reason, the importance of studies on bipedal robots is also increasing. In this study, the design of a biped robot, forward and inverse kinematics computation were made. Bipedal robot walking pattern and joint angle changes were determined according to the kinematic model of the robot and the power of the motors to rotate the joints. As a result of the walking pattern, center of mass and zero moment point change were tracked. As a result of the study, the stepping style, walking motion, gait analysis, changes in joint angles were determined of a bipedal robot.

  • TECHNOLOGIES

    • Exergy analysis of base and optimized high pressure feed water heating system from nuclear power plant

      pg(s) 103-106

      In this paper is performed exergy analysis of high pressure feed water heating system and all of its components which operates in nuclear power plant. Four cases are observed: system operation in the base case and system operation in three optimized cases. Exergy analysis show that optimization by using different algorithms has a different influence on the exergy destructions, while all the algorithms increase whole system and its components exergy efficiencies. An increase in the ambient temperature increases exergy destructions and decrease exergy efficiencies of the whole observed system and its components, regardless of operation case. The highest exergy efficiency of the whole analyzed system is 96.12% and is obtained by using an IGSA algorithm at the lowest observed ambient temperature of 5 °C. By observing exergy destructions only, it should be noted that GA and IGSA algorithms give almost identical results.

    • Studies on bimetallic ingots for armour by the methods of non-destructive testing

      pg(s) 107-109

      We have carried out researches for working out technological electroslag remelting conditions to produce bimetallic ingots. A new plant flow diagram has been developed for the manufacture. Experimental series of melting was performed on a laboratory electroslag remelting installation by developed by us electroslag remelting conditions. Bimetallic ingots for armour were produced of different combinations steel grades. Ingot of X38CrMoV 5 1 (DIN 1.2343; AISI H11) -10G2SF perspective steel grades is investigated. By the method of non-destructive testing the fusion of two steel grades along height of ingot is investigated. Macrostructure of cast transverse templates is investigated. A complete fusion of steels is established.

    • Improving the Corrosion Resistance of Carbon Steel Cylindrical Pipe by Nano-Materials Coating, Part -1.

      pg(s) 110-116

      Recent research has shown that the Nano coating materials play a vital role in improving performance of corrosion resistance in hostile environment and enhancing the mechanical properties and reducing the dimension changes. Due to the superior capabilities of Nano coating in many benefits which can be achieved, in addition to corrosion resistance, mechanical properties, make it smoother, stronger and improves its adhesive properties. In this work, the effect of anti-corrosive nanomaterials (Cobalt and Zinc) coating on chemical corrosion behavior and mechanical properties of carbon steel cylindrical pipe were studied in detail. The Nano-coating was done with different thicknesses (300nm,600nm,900nm and 10 μm), then analyzed using ANSYS software technology (version .19).The results showed that there is a strong relationship of corrosion improvement with improving mechanical properties, especially surface deformation resistance, elastic strain and stresses reduction of the inner pipe surface which contains a pressurized corrosive fluid. The maximum improvement was with the thickness of the cobalt coating (10 μm. The result of improvement in corrosion resistance of the cobalt-coated surface is approximately (5.165%) compared to the uncoated surface, also, the results showed an improvement in mechanical resistance and corrosion res istance because of deposition of cobalt particles better than zinc particles in all different thicknesses, with a maximum of about (66%) compared to zinc. Therefore, can conclude that the improving corrosion resistance due to coating with nanomaterials is very promising.

    • Technologies for joining dissimilar materials in the automotive industry

      pg(s) 117-120

      The paper presents the results of research aimed at determining the quality of welds in steel and aluminum alloys. Laser welding technology, fusion-pressure welding in combination with adhesive bonding were used for joining. The present research describes a new bonding technology based on the resistance welding process with a combination of adhesive bonding. Its implementation allows the joining of aluminum and steel sheets at extremely short welding times with a high concentration of energy in combination with adhesive bonding. The quality of the joints was determined on the basis of the tensile shear test according to ISO 12996.

    • Influence of external mechanical loads on change of electrophysical characteristics of film sensor elements

      pg(s) 121-127

      The materials of the article consider the influence of external mechanical loads of static and dynamic action (pressure force, mechanical impulse, vibration) on the change of electrophysical characteristics (electrical conductivity, specific capacitance) of film sensor elements. It is shown that an increase in the mechanical load on such an element with a simultaneous decrease in the interact ion time with a constant contact area leads to an exponential increase in the power and sensitivity of the reaction pulse, provided that such mechanical load does not exceed the mechanical strength of the sensor element. At the same time, the increase in the mechanical load on the sensor element at constant time and contact area, almost does not change the sensitivity of the reaction pulse (the maximum increase in sensitivity does not exceed 1.8%). In this case, vibrational oscillations in the frequency range 30… 85 Hz at mechanical forces of the order of 20 … 150 mN create response pulses of the order of 12… 45 mV/μs, which are perceived as “false positives” of the sensor elements. A further increase in frequency and mechanical effort leads to the destruction of the base of the sensor element and the detachment of the sensor f ilm from the base. Reducing the frequency and mechanical forces create reaction pulses up to 12 mV/μs, which does not exceed the allowable values of “white noise” (about 25… 35% of the minimum value of the reaction pulse).

  • MATERIALS

    • A high-performance Ti-Zr BASED conversion coating on 5556 aluminum alloy

      pg(s) 128-129

      The process of deposition of titanium, zirconium-containing coatings at aluminum alloy 5556 is developed. In the process of performing the work, the basic patterns of coating formation were identified. The solution composition and process parameters were optimized, and the physicochemical properties were investigated. It is shown that passivation of aluminum alloy 5556 in a titanium,zirconium-containing solution increases its corrosion resistance to pitting corrosion. These coatings can replace chromate coatings because of good ability to resist corrosion.

    • Attenuation of ultrasonic shear waves in polymeric materials

      pg(s) 130-131

      Ultrasonic non-destructive method has been applied to investigate different types of optical polymeric materials. Attenuation coefficients and paths lengths of normal incidence shear waves in the materials have been determined by means of the pulse -echo multireflection technique. Comparison among acoustic properties of the examined polymers and the standard polymethyl methacrylate test sample at 5MHz frequency is carried out. Obtained results are used to qualify homogeneity and isotropy of studied materials.