Department of statistical dynamics and multidimensional mechanical systems dynamics

Acting head of department – PhD, senior researcher Tetiana F. Mokriy

Tetiana F. Mokriy

Field of research – random oscillations and motion stability of mechanical systems; identification and optimization of their parameters; vibration protection of structures; prediction of vibration load and strength of engineering structures, including vehicles and rocket and space technology products, at operational and excess loads; dynamics of land, air, sea types of launch of liquid-propellant launch vehicles for spacecraft and dynamics of launch of operational tactical missiles and multiple launch rockets; stationary and non-stationary oscillations of an inhomogeneous freight train; dynamic workload and stress-strain state of structural elements of the passenger train crews with a passive safety system under operational driving conditions and emergency collisions, stability and safety of high-speed rolling stock traffic.

Methods to study steady and unsteady random oscillations of complex mechanical systems have been developed, methods to identify and optimize their parameters have been proposed; mathematical simulations and methods have been developed to solve the problems of statistical dynamics of vehicles and transported goods. Using these methods, a number of tasks of important national economic importance, problems of vibration protection of machine structures and structures, including various vehicles, masts, TV towers in Tashkent, Almaty, Riga, and vibration loading of rocket and space technology products in ground, sea and air transportation, which allowed to accelerate their creation, reduce metal consumption, increase reliability and durability.

A large amount of applied research has been conducted, in particular, in the interests of transport engineering as one of the most metal-intensive and energy-intensive sectors of the national economy. So, by orders of the USSR Ministry of Transport and Logistics, a full cycle of in-depth dynamic calculations of a number of universal and specialized rail crews was created, as well as recommendations on the selection of the main parameters of the designed vehicles that are rational in terms of ensuring their strength and dynamic qualities, preservation and vibration protection of transported goods, traffic safety.

For example, the department participated in the creation of a platform car for the transportation of large freight containers, a long-wheelbase universal platform with an increased axle load, bunker-type cars for the unpacked transportation of flour and polymers, multi-axle conveyors with a carrying capacity of 700 tons, a carriage for carrying trucks, a rake truck , dumpcars, mixers, specialized chassis for freight cars, a unified carriage for the chassis of multi-axle conveyors, electric train cars, trolley buses, trams, series special rolling stock for transportation of objects of rocket and space technology, etc.

Participation in the creation of new vehicles for transport engineering was marked by government awards, a diploma of the State Committee for Science and Technology of the USSR, medals of the USSR and the Ukrainian Exhibition of National Economic Achievements.

Mathematical simulation and software have been developed for the automated control system for vibration testing of vehicles at the most powerful stand of the Yuzhnoye State Design Office in the CIS and Eastern Europe, which allows you to set deterministic and random disturbances in three planes and test any assembled railway car. In this case, the load conditions are determined on the basis of the collected and generalized in the ITM data on the real action from the side of the track.

One of the priority areas of the department’s activity is the development of methods and software for studying the dynamics of land, air and sea types of spacecraft launch, taking into account the features of non-linear interaction of the spacecraft with the launcher, the variability of the wind flow velocity along the length of the spacecraft, the possibility of non-synchronous start-up of the first stage engines and change in the structure of the system in the process of movement. The developed mathematical models and software were used by Yuzhnoye State Design Office to develop the technology for launching Zenit, Dnepr, and Cyclone-class launch vehicles and selecting the engine start cyclograms.

Methods and software have been developed for the study of the dynamic loading of spacecraft launch vehicles and were included as part of a series of works awarded the Prize of the NAS of Ukraine named after M.K. Yangel in 1998.

A mathematical model of the interaction of the launcher support elements with the soil under the action of a short-term dynamic load has been developed to analyze the dynamics of the launch of operational tactical missiles and multiple launch rockets, as well as to assess the residual deformations of the soil base.

Theoretical studies have been performed on the selection of parameters of elastically dissipative devices that provide a significant reduction in vibration loads acting on the spacecraft during air, road and rail transportation.

The department has conducted a study to determine the hydrodynamic characteristics of tanks, partially filled with liquid. A number of practically important experimental results were obtained.

A special place in the work of the department is devoted to solving the problem of creating high-speed rail transport in Ukraine. The department has some experience in conducting research on this topic. In 1994, the ITM, together with the Yuzhnoye State Design Office, Dnipro National University of Railway Transport, Luganskteplovoz, developed a draft state scientific and technical program “High-Speed Rail Transport of Ukraine”.

At present, one of the promising areas of the department’s work is the development of scientifically based solutions related to the safety of passengers and goods, as well as the creation of railway crews equipped with passive protection.

Mathematical simulations and corresponding software have been created for studying the spatial vibrations of railway crews, taking into account their design features, physical and geometric non-linearities of the system, the operation of couplers, the technical condition of the rail track, and the specifics of the transported cargo.

Methods have been developed that allow using computer simulation to study the dynamic processes that occur during the movement of individual cars and locomotives and trains on sections of a path of arbitrary shape both in operating conditions and in emergency situations associated with the possibility of individual cars coming off the rails, train collisions and collisions of trains with an obstacle.

Mathematical simulations and software have been developed to study the dynamics of high-speed passenger trains in excess collisions caused by an emergency collision of a train with an obstacle on a railway track, taking into account the description of the power characteristics of the intercar joints of the initial tightening of absorbing devices, the features of the SA-3 automatic couplings and clearance-free coupling devices, crew structures, as well as elements of the passive safety system.

Based on theoretical studies, a system for technical diagnostics of the state of running gears of a passenger train has been developed. The system allows you to carry out operational control of the technical condition of the running gear of cars and tracks directly in the process of movement, which helps to increase the safety of the transportation process.

Methods, discrete-mass and finite-element mathematical models have been developed for studying the dynamics, loading and stress-strain state of structural elements of tank cars, including those equipped with means to protect the bottoms from penetration in an emergency, during operational and excessive shock actions.

Technical proposals and practical recommendations on the creation of effective means of protecting the bottoms of the boilers of new-generation tank cars in emergency situations have been developed. A design of a safety end shield with honeycomb energy-absorbing elements fixed to the frame of a tank car has been proposed, a method to determine the rational parameters of a protective structure has been developed. The resulting technical solution is protected by patents and introduced into production.

The research results were used when creating, together with the Mariupol Heavy Machine Building Plant, a new frameless design of a four-axle tank car for Indian railways and a tank car model 15-9803 WUA for transportation of liquefied gas, the boiler bottoms are equipped with end safety shields of the proposed design.

A technique based on the synthesis of computer-aided geometric design and finite element modeling has been developed to study the stress-strain state of structural elements of locomotives and passenger cars equipped with passive protection under shock loads characteristic of operation and emergency collisions.

Mathematical models have been developed for the dynamic analysis of the elastic deformation of the frame elements of the cab of a high-speed passenger locomotive with a passive safety system for shock loads arising in emergency situations, taking into account nonlinearities, the dependence of the yield strength on the strain rate, and the variable contact interaction of structural elements with an obstacle and with each other.

The design of an energy absorption device for the passive safety system of a passenger locomotive in emergency collisions was developed and patented in Ukraine.

A full-scale crash test of the developed energy absorption device at the test site in G?rlitz (Germany) was performed.

Based on the results of the research, a modular cabin of a new generation high-speed passenger electric locomotive driver with elements of a passive safety system was developed, manufactured and put into production. An electric locomotive with a developed cabin and energy absorption devices was put into operation.

As a result of mathematical modeling of the dynamics of reference trains in emergency collisions, the scenarios of which correspond to the European standard EN 15227 for passive safety, the designs of energy absorption devices containing cellular elements and designed for installation in the ends of passenger locomotives and cars have been developed. The proposed devices can protect passengers and crew in emergency train collisions with obstacles.

A series of theoretical and experimental studies has been conducted that are closely related to solving the problem of updating the freight fleet of Ukraine’s railways in order to increase the dynamic qualities of crews, increase the resource of running gears, and reduce wear on rolling stock and track elements. Based on the results of these studies, a comprehensive upgrade of freight car trolleys was proposed for the railways of the CIS and the Baltic countries. In wheelchairs, poorly functioning standard side-bearings with constant-contact side-bearings were replaced; instead of steel wedges, wedges of ductile iron are installed; friction plates are replaced by steel wear-resistant; polymer gaskets are laid in the thrust bearing. At the same time, the best models of the upgrade elements of the company’s development A. Stakey (USA) were used. The wheel rim profile has also been changed to non-linear wear-resistant ITM-73 (the ITM development).

Using this upgrade, it was possible to achieve a more than twofold increase in the wheel resource in terms of flange wear, a more than tenfold decrease in wear in the wedge damping system, a 4-5-fold reduction in the wear of the center plate arrangement.

Since 2004, a comprehensive upgrade of trolleys, mainly gondola cars, the percentage of which in the freight car fleet is about 48%, has been conducated on Ukrainian railways. Now with upgraded carts on the Ukrainian railways, more than 24,000 wagons are operated (about 33% of the gondola car fleet).

The indicated modernization of the carts was proposed for implementation on the railways of Russia, the CIS countries and the Baltic states (with a gauge of 1520 mm). The research groups of open wagons on railways have been upgraded in a number of the CIS countries (Russia, Belarus, Kazakhstan).

Recommendations were developed and tests have been conducted on the upgrade projects for carts of other types of wagons, the carts of which should be upgraded.

Elements of the ITM’s proposed comprehensive upgrade of standard bogies were fully used in the creation of the first three models of Ukrainian freight wagon bogies: models 18-7020 and 18-7033 developed by Kryukovsky Car Building Plant, as well as models 18-4129 developed by KB Sofia-Invest LLC. The first of these bogies was put into mass production (more than 2000 have already been in operation), while others have successfully passed experimental tests.

To continue the work to improve the comprehensive upgrade of freight car carts, a new, more wear-resistant ITM-73-01 wheel profile was created. As operational tests of freight cars with comprehensively upgraded bogies have shown, the use of the ITM-73 profile first for unworn wheels, and then, when turning, the ITM-73-01 profile allows to increase the wheel life (compared to standard wheels) by more than four times.

By order of Ukrzaliznytsia, the use of the ITM-73-01 profile is mandatory when regrinding the wheels of complex upgraded freight car trucks.

Research is being conducted on the creation of a wear-resistant profile of wheel tires for traction rolling stock and freight cars with increased axial load.

One of the areas of work of the department is the study of the biomechanics of total hip arthroplasty. To assess the stress-strain state of the bone-implant system during its operation, finite-element calculation models have been developed both for a healthy hip joint and in the case of using an endoprosthesis with various types of acetabular component, which is installed by pressing or screwing into the acetabulum.

The main results are published in the books and articles:

  1. Ushkalov V. F. Statistical dynamics of rail vehicles / V. F. Ushkalov, L. M. Reznikov, S. F. Redko – Kiev : Naukova dumka, 1982. – 360 pp.
  2. Self-oscillations and Rail Vehicle Motion Stability (in Russian) / Yu.V. Demin, L.A. Dlugach, M.L. Korotenko, O.M. Markova. – Kiev : Naukova Dumka, 1984. – 160 pp.
  3. Redko S. F. Identification of mechanical systems. Determination of the dynamic characteristics and parameters / S. F. Redko, V. F. Ushkalov, V. P. Yakovlev – Kiev : Naukova dumka, 1985. – 216 pp.
  4. Mathematical modeling of rail vehicles / V. F. Ushkalov, L. M. Reznikov, V. S. Ikkol and others. – Kiev : Naukova dumka, 1989. – 240 pp.
  5. Korenev B. G. Dynamic Vibration Absorbers. Theory and Technical Applications / Korenev B. G., Reznikov L. M. – Chichester : J. Wiley and Sons, 1993. – 304 p.
  6. Demin Yu. V. Dynamics of engineering and transport structures at non-stationary effects / Yu. V. Demin, G. I. Bogomaz, N. Yu. Naumenko. – Kiev : Naukova dumka, 1995. – 189 pp.
  7. Bogomaz G. I. Liquid fluctuations in tanks / G. I. Bogomaz, S. A. Sirota. – Dnipro : ITM of the NASU and SSAU, 2002. – 305 pp.
  8. Bogomaz G. I. Dynamics of rail tank cars / G. I. Bogomaz. Kiev : Naukova dumka, 2004. – 223 pp.
  9. The dynamics of the start in liquid-propellant spacecraft launch vehicles / G. I. Bogomaz, N. Yu. Naumenko, M. B. Sobolevskaya, I. Yu. Hizha. – Kiev : Naukova dumka, 2005. – 248 pp.
  10. Rail vehicle dynamics and associated problems / A. Sladkowski, H. Scheffel, H. Kovtun, O. Markova, W. Kik, D. Moelle. – Gliwice : Silesian University of Technology, 2005. – 118 p.
  11. Stress loading of tank cars with transient trains / G. I. Bogomaz, N. Yu. Naumenko, A. N. Pshinko, S. V. Myamlin. – Kiev : Naukova dumka, 2010. – 215 pp.
  12. Ushkalov V. F. Freight-car truck retrofit as the upgrade option of freight rolling stock running parts / V. F. Ushkalov, A. D. Lashko, T. F. Mokriy // Vestnik of Joint Stock Company Railway Research Institute. – 2013. – # 5. – P. 8 – 15.
  13. Sobolevska M. Passive safety system of an electric locomotive for high-speed operation on the railways with 1520 mm gauge / M. Sobolevska, I. Telychko (Соболевская М.Б. Система пассивной безопасности пассажирского электровоза для скоростного движения по колее 1520 мм / М. Соболевская, И. Теличко) // Passive Safety of Rail Vehicles 2013 : Railway Research Network Proceedings of the 9th International Symposium “Passive Safety 2013 – Passive Safety of Rail Vehicles and Safe Interiors” in Berlin on 21 – 22 February 2013. – 43/2013. – Berlin : IFV Bahntechnik e.V. – 2013. – P. 63 – 80.
  14. Naumenko N. Ye., Markova O. M., Kovtun Ye. N., Malyi V. V. Measurement of strains of soil base under short-time loads // Тekhnicheskaya Мekhanika, 2015, # 2 , р. 71-78
  15. Markova O. Modelling train motion along arbitrary shaped track in transient regimes / O. Markova, H. Kovtun, V. Maliy // Rail and Rapid Transit. – 2015. – Vol. 229(1). – P. 97-105.

On a number of issues related to solving the problems of dynamics of engineering and transport structures, the department cooperates with the Yuzhnoye State Design Office, PJSC Krukovka Carriage Works, Azovmash Open Joint-stock Company, Design and Engineering Production Enterprise MDS LLC, Dnipropetrovsk National University Railway Transport named after Academician V. Lazaryan, Institute of Mathematics, the National Academy of Sciences of Ukraine (Kiev), All-Russian Research and Design Institute of Rolling Stock “(Kolomna), Saint-Petersburg State University of Railway Engineering, JSC” All-Russian Scientific Research Institute of Railway Transport “(Moscow), Technological University (Delft, Netherlands), European Institute for Railway Research (Utrecht, Netherlands), Berlin Technical University (Germany), Metropolitan University (Manchester, UK), the Royal Institute of Technology (Sweden), University of Rome La Sapienza (Italy), Dnipropetrovsk State University of Medical Academy, actively cooperating on improving rolling stock designs with American companies, “A. Staki “and” Amsted Rail “, the German company” EST Eisenbahn-Systemtechnik GmbH “, as well as with other organizations of the CIS countries and abroad.

OFFICE ADDRESS:Institute of Technical Mechanics , 15 Leshko-Popelya St.,
49005, Dnipro, Ukraine,
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The “Technical Mechanics” Journal

Frequency: 4 times a year

Languages: Ukrainian, English

Editor-in-Chief: Oleg V. Pylypenko, Academician of the National Academy of Sciences of Ukraine