Department for Reliability and Dynamic Strength

Head of Department:
Doc. Sci. (Eng.), Professor

Avramov Konstantin Vitalievich

E-mail: kavramov@ipmach.kharkov.ua

Department for Reliability and Dynamic Strength

The department was set up in 1972 under the leadership of Prof. Bozhko Aleksandr Yevgenyevich, and it is staffed with highly qualified specialists. The results of basic and applied research are presented in 17 monographs, 730+ papers and 255 inventions. The developments have been implemented in power machine, engine and ship building, and in the aerospace industry.

Main research topics

  • Assessing and forecasting the reliability and life of power machinery operating in vibration and shock conditions
  • Vibration technologies
  • Vibration protection
  • Vibration tests
  • Vibration diagnostics
  • Monitoring systems and optimal control of vibration systems
  • Analysis and synthesis of the strength properties of elements and systems of mechanical engineering constructions under nonstationary and vibration loads with account of technological and service factors
  • The features of vibration of complex mechanical systems, including systems with mistuned guide vanes and other systems of elements in steam, gas and hydraulic turbines
  • Experimental and theoretical research in high-speed strain of materials and construction elements under short-time loads
  • The scientific fundamentals of the manufacturing processes of impulse treatment of materials and construction elements (shaping, separation, joining, and repair and rehabilitation work)
  • Diagnostics of the bearing capacity and assessing the strength reliability of products and systems

Basis research

  • Controlling mechanical vibrations in dynamic testing, reducing residual stress in cast and welded constructions, and active vibration protection of machines and instruments. Developing the theory of reproducing stochastic vibrations in vibration reliability tests of machines and instruments. Developing the theory of optimal control of vibration systems. Developing the theory of electrodynamic excitation of mechanical vibrations. Advancements in theoretical mechanics when defining the dynamic and energy links in vibration systems
  • Dynamic strength and accelerated dynamic testing of parts and assemblies of power machinery. Developing methods for accelerated dynamic tests, integrated criteria of assessing and predicting the fatigue life of power machinery. Developing methods for investigating the link between reliability and the fatigue strength of products. Developing the principles of building 2 and 3-coordinate vibration beds around mechanical, electromechanical and hydrostatic coupling units
  • Vibration diagnostics and defectoscopy of power machinery parts and equipment. Developing methods for vibration diagnostics and monitoring the technical condition of compressor units at gas pumping stations, and of automotive and marine engines. Developing methods for detecting surface cracks in metal parts and constructions of power equipment
  • Effective usage of electromagnetic energy for exciting mechanical vibrations for vibration-shock testing of power machinery and production processes. Developing methods for electromagnetic excitation of vibrations and shocks for vibration testing of objects and production processes. Working out the principles of building multi-coordinate electromagnetic vibration beds. Developing methods for active vibration protection of objects based on electromagnetic vibration exciters
  • The physical basics of reducing residual stress (vibration ageing) during vibration loading of cast and welded constructions and elements of power machinery. Developing highly effective methods of vibration reduction of residual stress in parts and constructions of power machinery. Developing methods of overall loading of machine parts to reduce residual stress and stabilising their geometric and strength parameters. Developing the theory of systems for searching for and maintaining resonance vibration treatment conditions, and assessing the dynamic performance of power installation components, and of measuring and monitoring the process of reducing residual stress
  • Analysis and synthesis of the strength properties of elements and systems of mechanical engineering constructions with account of design, technological and service factors
  • Experimental and theoretical research in the thermal elastoplastic processes of high-speed strain in materials and constructions
  • Developing methods and means for assessing the strength reliability and residual life of structural elements in modern engineering areas with account of the features of the material mesostructure
  • Analysing the impact of hardening treatment on the characteristics of contact interaction of a cutter with the machined material

Applied research

  • Developing means for vibration diagnostics and monitoring the technical condition of power equipment, compressor units at gas pumping stations, and of automotive and marine engines. Developing methods and systems for monitoring and identifying the causes of excess vibration in gas pumping stations. Developing techniques and devices for vibration diagnostics of defects in anti-friction bearings in rotor machines
  • Developing technical means for accelerated dynamic tests, assessment and prediction of the fatigue life of power machinery
  • Developing systems for vibration loading of reconditioned parts of power machinery to relieve residual stress and stabilize their geometric and strength parameters. Developing systems for searching for and maintaining vibration treatment resonance conditions, and assessing the dynamic performance of power installation components. Developing instrumentation for measuring and monitoring the process of residual stress reduction
  • Development and technical implementation of 2 and 3-coordinate vibration beds built around mechanical, electromechanical and hydrostatic coupling units
  • Developing technical means for monitoring unbalances and balancing of rotors in rotor machines. Developing systems for protecting power machinery from vibration overloads
  • Developing methods and technical means for defectoscopy of products made of electrically conducting and dielectric materials
  • Developing systems for electromagnetic excitation of vibrations and shocks for vibration testing of objects and production processes. Developing a 2-coordinate electromagnetic vibration bed and a control system for exciting spatial vibrations of a casting mold for making non-ferrous metal and alloy castings
  • Analysing the dynamics and statics of guide vanes in turbomachines with account of design, technological and service factors, including mistuning and damages
  • Analysing the vibrations and the statics of runners and assemblies in the stator-scroll chamber of hydraulic machines
  • The scientific fundamentals of the manufacturing processes of impulse treatment of materials and construction elements (shaping, separation, joining, and repair and rehabilitation work)
  • The scientific fundamentals of hardening materials, applying coatings and creating the structure of complex materials (bimetals and composites)
  • Diagnostics of the bearing capacity and assessing the strength reliability of products and systems

COMPLETED DEVELOPMENTS

Monitoring and emergency protection system for gas pumping units

Crack indicator IT-22

Method and technical means for accelerated reliability tests of fans

Procedure for assessing the residual life of bearing assemblies in reducing gear of escalators type LT-3, LT-4 and ET-3

Investigating the cyclic strength of box retainers in railway passenger cars

Computerised resonance system for accelerated vibration testing of parts and assemblies in machines

Complex of programs for analysing the vibration-stressed condition of steam turbine rotor blades

Collection of methods for calculation and analysis of vibrations of complex systems with identical and similar elements

Design and experimental evaluation of the strength reliability and life of elements of constructions at all stages of their life cycle

Software package for CAD of composite materials with specified strength properties

Analysing the oscillations and static strength of blading and other components of turbo machines

DEVICE CONTROL QUALITY OF SOLDER CONNECTIONS "LINER - STATOR WINDING" SYNCHRONOUS GENERATORS

    It is intended to determine the level of quality of soldering controlled compounds is based on the experimentally established the connection between the device and the testimony of quality of soldering these compounds.
    The principle of operation of the device is based on the method of eddy currents. Parameter control is the voltage measurement of transformer winding eddy current transducer core asymmetric П-shaped type, the value of which depends on the state-controlled solder joint.


Technical characteristics:

    Control of quality of soldering copper interconnect thickness, mm up to 20
    The range of values of controlled of quality of soldering, % from 0 to 100
    The ability to hot-swap (changing sizes controlled connects) eddy current probes
    Display results in digital form with the ability to set and store information (1000 memory locations)
    Data transfer to PC via USB port
    Sound and light alarm "rejection" level
    Autonomous power (batteries)
    Overall dimensions of the device, mm 190×90×40
    Mass device kg, not more than 0,5

    For synchronous generator unit provides quality control of solder joints "sleeve - stator winding", an important parameter that affects reliability. Degree of quality of soldering compounds in percentage is displayed on the digital display. Smart algorithm of the device allows you to customize its settings according to the control objectives.
    Companies producing electrical products.
    The device has been tested at the state enterprise plant “Electrotyazhmash”.

Contact Information:     Polishchuk Oleg Fedorovich         Tel: +38(057) 349-47-14     Fax: +38(0572) 94-46-35     Е-mail: polishchuk@ipmach.kharkov.ua

Methods of on-line diagnostics of surfaces condition of manufactured articles

    Microprocessor-based device – diahardprofilometer ensures simultaneous complete control, efficient determination and selection of optimal parameters of initial roughness, microhardness and form deviation or work surfaces arrangement during their making, operation or repair, promotes developing the new energy-saving computer technologies of optimal treatment of these surfaces.
    The proposed technology replaces replica or visual methods of in-process measurements of surfaces irregularities of different details, allows to get the total evaluator of surfaces condition of manufactured articles with the help of one device - diahardprofilometer With the help of this device it is possible to define and set energy saving industrial regimes and also their sequence, which subject to current status of processing equipment, tooling can provide quality of treated surfaces under the condition of minimal allowance of work material and their productive time.
    This technology can be applied at enterprises where grinding or other surface treatment is carried out, also in measuring laboratories, certification centers and etc.
    Developed devices can be applied both in Ukraine and abroad, particularly, in European countries, USA, Canada, CIS, China, India and others.
    The first industrial consignment has been produced and applied at state enterprise “Electrotiajmash”

MINIDIAPROFILOMETER “PROFILE-03”

    The device is intended for measuring the micro and macro geometric parameters of the roughness of any plane or cylindrical hard-to-access surfaces of different parts. The inspection is a direct in-process one and can be applied in any production process using grinding or any other kinds of machining methods. The compact, stand-alone device can be used for measuring not only the micro geometric parameters of a part’s surface, but to check its diameters at the same time. The instrument replaces the visual and replica methods of in-process inspection.
    The minidiaprofilometer includes the following:
        • A miniature mechanical unit of the clock type with a magnetic induction speed regulator based on a permanent magnet
        • A mechanical unit with photo and piezodetectors, and resistive sensors
        • A portable electronic digital indicator unit
        • Certified roughness gages for calibrating and adjusting the device
        • A coaxial cable.

    Specifications


        Range of measurement of parameter Ra, µm          0.02 to 10
        Reduced measurement error, %,          max 5 to 10
        Feeler travel during measurement, mm          6
        Base measuring line sections, mm          0.25; 0.8 and 2.5
        Supply voltage, V
                - Storage battery option           15
                - Mains supply option           220, 50 Hz
         Overall size, mm
                - Mechanical unit (along measurement line), d          3.5
                - Electronic unit          70x140x170
        Warranty term, years          3

    The instrument’s mechanical unit is protected by documents of title.  Application of the instrument provides the following advantages:
        1. Effective usage of production space; extending the service life of abrasive and cutting tools by reducing machining time; more accurate finishing of surfaces being machined with respect to roughness and diameters specified in drawings.
        2. Detect and eliminate on spot any maladjustment of grinding machines and other machine tools.
        3. Reduce the number of reject parts.
        4. Increase the service life of different mating parts by complete inspection of micro and macro geometric parameters.
        5. Do away with the practice of using roughness and internal gauges at the workplace.
        6. Simplify certification of manufactured products.

    The instrument can be used not only in production, but also in metrological laboratories and certification centres. The tentative cost of the device is 7,000 USD.

BASIC RESEARCH

The Department has done the following:

Developed the principles of building resonance vibration testing systems based on electrodynamic vibration beds with forced control.

Offered methods for structural analysis of reliability of power machinery with account of its loading and the dynamic strength of its elements, and obtained expressions for defining the reliability indices of parts and systems operating under cyclic mechanical load conditions.

Developed the principles of building vibration condition monitoring and emergency protection systems.

Developed the applied theory and principles for selecting the power of electromagnetic vibration exciters.

Developed the principles of setting up and conducting vibration reduction of residual stress.

APPLIED RESEARCH

The Department:

Has developed systems for electromagnetic excitation of mechanical vibrations in melts for casting processes.

Offers methods and means for defectoscopy of products made of electrically conducting and dielectric materials.