This article presents the results of a set of innovative research to analyse a new structural material – steel like austempered ductile cast iron with mechanical properties similar to heat-treated steel, and with technological and exploitation characteristic close to high-strength cast iron with nodular graphite. Specific examples of its high efficiency for the manufacture of critical, mass and heavy-loaded components of modern machinery and equipment are presented. New structural material MoNiCa was tested on tension and was compared to commercial grades of austempered ductile cast irons and heat treated steels. Unconventional behaviour of examined material was observed: with tensile strength increase to almost 1600 MPa the metal became less brittle. Hardness test revealed another distinctive feature of new material that there is no linear relation between strength and hardness increase, different hardness values ~ 40 HRC or ~ 55 HRC can be achieved with the same tensile strength 1000 – 1200 MPa. Microscopic analysis demonstrated of sophisticated structure formed owing to different regimes of austempering treatment. Specific properties emerged from successful ratio of three elements Mo, Ni, and Cu (carbon equivalent), and properly chosen heat treatment modes. DOI: http://dx.doi.org/10.5755/j01.ms.25.3.23079

The paper presents results of experimental measurements of the parameters of rowing process when rowing in a river, on the pool-type training facility and on “Concept II” rowing machine. The comparison of results of measurements showed the significant difference of rowing force generated by rowing in the machine and in the boat, thus the novel training facility is proposed having the hydrodynamic loading unit equipped with proportional flow control valve controlled by computer evaluating parameters of rowing, which is able to ensure loading on the oars more adequate to the real rowing conditions.

The rowing force simulation and control system is to be developed to generate the loading on the oar during the rowing stroke most adequate to the one acting during waterborne rowing. The paper presents the methodology of defining the law of change of loading on the oar by changing the cross-sectional area of flow channel of hydraulic loading unit at indoor rowing training facility. An example of the rowing force variation during one cycle obtained by using such a system is provided.

This research presents the results of tribo-fatigue behavior of austempered ductile cast iron MoNiCa and gives a comparison with standard grades of steel and cast iron. Due to the possibility to combine the castability of cast iron and toughness of steel in one material, new structural material MoNiCa attracted attention of industry and science because of economic benefits and high performance at the different application areas. After successful former experiments the main directions of further development of research for solving relevant practical wear and fatigue problems in rail-wheel system were framed. The complex experimental studies have demonstrated that MoNiCa is consistent with heat treated steels including the rail steels: required tensile strength of rail steel ranges from 1180 MPa to 1280 MPa when rolling surface hardness have to be from 38 HRC to 44 HRC whereas new structural material showed higher tensile strength up to 1400 MPa and slightly higher hardness up to 50 HRC. Herewith the workability of frictional couple cast iron MoNiCa/steel 20MnCr5G exceeds work performance of steel/steel system by 14 %.

Training equipment used by professional sportsmen has a great impact on their sport performance. Most universal exercisers may help only to improve the general physical condition due to the specific kinematics and peculiar resistance generated by their loading units. Training of effective techniques and learning of psychomotor skills are possible only when exercisers conform to the movements and resistance typical for particular sports kinematically and dynamically. Methodology of developing a magnetorheological resistive exercise device for generating the desired law of passive resistance force and its application in a lever-type rowing machine are described in the paper. The structural parameters of a controllable hydraulic cylinder type device were found by means of the computational fluid dynamics simulation performed by ANSYS CFX software. Parameters describing the magnetorheological fluid as non-Newtonian were determined by combining numerical and experimental research of the resistance force generated by the original magnetorheological damper. A structural scheme of the device control system was developed and the variation of the strength of magnetic field that affects the magnetorheological fluid circulating in the device was determined, ensuring a variation of the resistance force on the oar handle adequate for the resistance that occurs during a real boat rowing stroke.