Designs of machine units are various. The structure of power transfers includes such units and details as a crankshaft, cogwheels, planetary mechanisms, boxes of transfers and others. With growth of speeds vibrating processes become more active. Forecasting of behaviour of such objects is connected with use of various settlement models, methods, the software. New opportunities give modern finite element software package as ANSYS, use of three-dimensional models. It enables more adequately to consider the mathematical and detailed geometrical information. In work approaches of construction of simple equivalent models of all machine unit as uniform dynamic system are discussed.As an example typical elements of power transfer a shaft and system a shaft-cogwheel are con-sidered. Calculations of a spectrum of frequencies are executed at use as traditional discrete, continuous and finite element models of software package ANSYS. Comparison of results has shown, that takes place both satisfactory accuracy for engineering calculations and some deviations.

Keywords:
spectrum of frequencies, transmissions, cogwheels, finite element models

Grishchenko V.N., Tomin O.S., Lomov S.G. Dynamical finite – element models of shafts transmissions machines in ANSYS. NTU «KhPI» Bulletin: Series «Dynamics and Strength of Machines». 2014. No. 58. Pp. 21-30. DOI: test

Experimental research of stress-strain state at the area of local volumetric surface defects of the pipeline systems is an important goal because results of the measurements are necessary for increasing of effectiveness of existing repair technologies using fiber reinforcement polymer composite materials. In this work the description of experiment carried out by the author is presented with statement of results. The experiment was devoted to strain gauging of a steel cylindrical shell with volumetric surface defect. The gas vessel of carbon steel was used in the capacity of a cylindrical shell. The tested vessel was pressurized by a plunger pump. The goal of the experiment is investigation of strain distribution at the area of the defect. With obtained results about strain distribution stress concentration factors in some dangerous places of the defect zone is also calculated.

Keywords:
cylinder shell, volumetric surface defect, strain gauging

Beschetnikov D.A. Experimental study of the strain state at the area of a surface defect in a steel cylindrical shell subjected to internal pressure . NTU «KhPI» Bulletin: Series «Dynamics and Strength of Machines». 2014. No. 58. Pp. 3-7.

The aim of this work of this develop is the experimental determination of the parameters of pressure fluid flow, natural frequencies and accelerations decrement individual marks pipeline forced vibrations caused by pulsations of the working fluid. Experiments were carried out using a vibration measuring complex designed by the authors. The theoretical results have been obtained on the basis of finite-element approach of using a core and shell models. The results obtained show the adequacy of the core and shell models when the natural frequencies and solving the problem of forced vibrations of pipelines. The resulting dynamic characteristics of the systems can be used to predict the reliability and guaranteed service life of pipelines.

Keywords:
pipeline, pulsating fluid pressure, decrement of vibrations, natural frequencies, stress, acceleration, finite element method

Vodka O.O., Tykhyj D.K., Trubayev O.I., Ul’yanov Yu.M. Investigation of pipeline dynamic characteristics under laboratory conditions . NTU «KhPI» Bulletin: Series «Dynamics and Strength of Machines». 2014. No. 58. Pp. 8-20.

An ensuring the safety of goods and passengers transportation is one of the priority areas of automotive engineering. This point is particularly important for the transportation of dangerous goods. Here, providing high level of movement smoothness during the transportation is a point of great impor-tance due to the possibility of negative influence of vibrations on such categories of goods. This is can lead to emergency situations. In the paper a design of specialized vehicle with two levels of suspension is presented and analyzed. The specialized vehicle has additional level of cushioning with nonlinear characteristic, which has quasi-zero stiffness. Such, suspension is able to realize a vibro-isolating state of the transporting dangerous goods. The paper deals with an experimental investigations of the vibrations during the transportations of the goods which are mounted on specialized vehicle. As experiments the road tests have been done. Experiments were carried out on the base of a measurement system “Ultra-V-I», which has been devel-oped at the Department of the Dynamics and Strength of Machines of the National Technical University “Kharkiv Polytechnic Institute” (Kharkiv, Ukraine). The measuring system consists of: a detector of vibration accelerations, an analogue-to-digital converter (ADC) and a portable computer. “Ultra-V-I” has a valid certificate of state metrological certification and allows to make a measurement of vibration acceleration at the point of investigated object.The paper considered the moving of specialized vehicle through a single roughness at different velocities. Thus, the cart moving on the road with asphalt concrete pavement at some fixed time moved a obstacle. The experiment was conducted at the speed of movement of 5, 10 and 20 km / h. The re-search has carried out separately for the vehicle without nonlinear vibration compensators and with them. Comparative analysis has shown that quasi-zero stiffness cushioning reduces the level of goods vibrations, so magnifying the movement smoothing.

Keywords:
specialized vehicles, ride smoothness, vibration, dangerous goods

Kalinovsky A.Ya., Larin O.O., Vodka O.O., Bashtavoj V.M., Kajdalov R.О. Experimental study of vertical vibrations of specialized vehicle with non linear suspension moving through a single roughness . NTU «KhPI» Bulletin: Series «Dynamics and Strength of Machines». 2014. No. 58. Pp. 31-38.

Considered the estimation and prediction of vibration condition of the working condition of the foundations for the entire period of operation. The bases are considered only as supporting structures steam turbines. A range of theoretical and experimental studies. Studies conducted on the basis of previously developed мethodics. Object of research is the foundation of the steam turbine unit employed domestic power. Calculated study based on the finite element method. For experimental studies used diagnostic system. This diagnostic system specifically designed for dynamic measurements of vibration in a wide frequency range. Based on these data, the following: assessment of working conditions in the individual periods of operation, assessment of the current condition and forecasting the final state of the turbine foundation. Powered condition curve design. The resulting residual shared resource and the foundation of the steam turbine. Make recommendations for the future operation of the foundation. The results used in practice for a steam turbine unit of national power.

Keywords:
performance, vibration condition, vibration, foundation, steam turbine

Krasnikov S.V. Model of capacity for work of steam turbine foundation . NTU «KhPI» Bulletin: Series «Dynamics and Strength of Machines». 2014. No. 58. Pp. 39-43.

The paper presents the results of modeling of semi-trailers random vibrations of driving on dif-ferent type of roads. Damage to the tank capable appears during operation due to the accumulation and development of fatigue or corrosion, which leads to cracks and depressurization boiler tank. Therefore, development of methods for modeling settlement tank designs to assess their durability and reliability prediction as the design stage and in operation to ensure safety is important. For solving problem ran-dom vibrations of vehicle with the influence of the lag effect the mathematical model was made. Par-ticularly was considered the mathematical model random impacts vector with lag time effect on axis of vehicle. Finite-element model of the boiler semitrailer tanker was developed. The problem of natural vibrations was solved using the FEM, obtained natural frequencies and shapes. The natural frequencies has dense spectrum which are composed from groups of close to the frequencies. These groups are measure up to forms which responsible for local vibrations neighboring breakwaters. The next step was obtained probabilistic behaviors of the system, such as spectral density and standard deviation of dis-placements and stresses, the influence of the lag effect of external forces using the methods of statistical dynamics. After analysis of spectral density of displacement and stress was determined that in account of time lag spectral density has a lot of bursts, in contrast simultaneous load, which reflect phase shift in load. In paper has been determined that the distribution of the standard deviation at the same time load-ing and time lag effect is different. The largest amplitude in the first case the edges of the tank and the second in the middle. When analyzing the standard deviation stresses determined that there are danger-ous zone near the supports and hatches.

Keywords:
Sami-trailer, random vibrations, boiler tank, vehicle, random response, PSD, FEM

Larin O.O., Grinchenko K.E. Vibrations of a biaxial tanker with account time lag effects of random excitation . NTU «KhPI» Bulletin: Series «Dynamics and Strength of Machines». 2014. No. 58. Pp. 44-60.

This paper deal with developing software, which is an additional to SolidWorks, allows to tem-plating and to automating performing different types of analysis. Realized the possibility of remote and cloud analysis. The relevance of cloud calculations lies in the fact that they significantly save computer resources and eliminates the need to install additional software (CAD / CAE systems).The article pro-vides a basic description of the developed product and the technology of its developing and rationale for the selection of these technologies. Describes the basic steps needed to do for each of three types of analysis. The possibility of two types of analysis (local and cloud) of developed product are shown in test calculations to determine the Eigen frequencies and forms of turbogenerator rotor TGV-200M, the purpose of which is to determine the resonant frequency. Based on the testing shows the advantages of cloud calculations.

Keywords:
cloud computer system, SolidWorks, analysis

Leleka S.V., Vodka O.O. The cloud computer system for automation of engineering calculations using CAD SolidWorks . NTU «KhPI» Bulletin: Series «Dynamics and Strength of Machines». 2014. No. 58. Pp. 60-68.

In this paper a numerical-analytical study on a stress-strain state of a steel pipeline section with a repair fiberglass viscoelastic layer is described. The layer is considered long enough that allows to solve the problem in a flat axisymmetric statement. A mathematical model of viscoelastic behavior of a fiber-glass is proposed, moreover this model allows to simulate an order of anisotropy of viscoelastic proper-ties that exceeds an order of anisotropy of elastic ones. To mirror viscoelastic behavior of the construc-tion more correctly an orthotropical viscoelasticity is used in the mathematical model. As a result of transformation of the original system of equations of elasticity theory it becomes necessary to solve the inhomogeneous integral equation. In order to solve it quadrature formulas are used. With help of them an iteration process in time was built where an inhomogeneous differential equation with viscoelastic prehistory in right side was solved. For determining values of integration constants of differential equa-tions boundary conditions are rearranged using quadrature formulas. For the case of definite values of physical and geometrical parameters of the construction the right rectangle formula was chosen. To evaluate an error of the mathematical model a discrepancy between the analytical results form previous research and the results according to the given model for the simplified isotropic set of viscoelastic parameters was estimated. It is shown that for 500 iterations the discrepancy is less than 0.1% that al-lows to use this values for further calculations. Calculation results for the case of orthotropic viscolas-ticity are presented as displacement and stress distributions versus time curves. Also a comparison be-tween this results and the stress strain state of the construction in case of isotropic viscoelasticity was made. It is shown that even for a slight deviation of viscoelastic model from isotropic to orthotropic a change of the main parameters of the stress strain state is approximately 20% considering their time varying parts. Based on this fact a conclusion about a necessity of using the analytical model of orthtropic viscoelasticity in calculation or, at least, evaluation of the stress strain state of constructions with viscoelastic parts was made. Also built numerical-analytical model allows to disseminate the re-sults on cases of more complex geometrical and physical conditions without changing in a main idea of the method.

Keywords:
repair layer, orthotropic viscoelasticity, integral equation, quadrature formula

Lvov G.I., Martynenko V.G. Numerical-analytical study of orthotropic viscoelasticity of fiberglass illustrated by repair layer of main pipeline. NTU «KhPI» Bulletin: Series «Dynamics and Strength of Machines». 2014. No. 58. Pp. 68-77.

A literature review and an assessment of a current state of issues related to the rotor dynamics considering a use of various types of bearings in rotary engines are performed. The causes of different types of vibrations in rotary machines and variants of their manifestations, depending on features of the system, methods for identifying these vibrations and approaches for the dynamic analysis are reviewed. The main attention is paid to one of the new types of bearings – namely, a magnetic bearing. For this kind of supports of rotors survey studies on a classification of their existing types and investigation of the peculiarities of their application in various rotary machines are made. An analysis of sources of an origin and methods of a mathematical description of various dynamic phenomena possible in systems with magnetic bearings is performed. The particular attention is paid to the non-linear dynamics. The main current research topics in the field of simulation of a dynamic behavior of rotor systems with magnetic bearings are identified and systematized.

Keywords:
rotor dynamics, magnetic bearings, nonlinear dynamics

Martynenko G.Yu. History, actual problems, methods and phenomena analysis tools of rotor dynamics taking into account traditional and magnetic bearings . NTU «KhPI» Bulletin: Series «Dynamics and Strength of Machines». 2014. No. 58. Pp. 77-131.

The technique for calculating the natural vibration frequencies of hydro turbine lid in vacuum, in contact with water and taking into account the pre-stressed state of the structure is presented. Functionality of the proposed approach was checked on the test case, and the accuracy of the results, obtained on its basis was confirmed. The results obtained due to the proposed approach differ from the experimental data by 0.5-11%. The difference between the results obtained based on the proposed approach and calculated by the formula is 0.9-15%.Based on the methodology, analysis of the influence of factors on the first natural vibration fre-quency of the hydro turbine lid structure in a vacuum and taking into account the effect of water and the pre-stressed state of the structure was performed.It was found that in this structure of the hydro turbine lid: hydroelastic vibration frequency decreases with an increase in the water volume depth; vibration frequency decreases with an increase in mass loads M; vibration frequency decreases with an increase in water pressure; consideration of the pre-stressed state has no significant effect.

Keywords:
vibrations, pre-stressed state, intrinsic pressure, hydro turbine lid

Misiura S.Y. Influence of structural parameters and operational factors on the vibration frequencies of hydroturbine lids. NTU «KhPI» Bulletin: Series «Dynamics and Strength of Machines». 2014. No. 58. Pp. 132-140.

Present paper is devoted to an experimental determination of the Bauschinger effect and material damage which occur at elastic-plastic deformation. The series of cyclic tension-compression tests of flat samples made from aluminum alloy D16 were conducted. Given a phenomenon of buckling at compres-sion stage the flat samples were cut according to both ATSM standard and preliminarily conduction of the buckling analysis. Based on the experimental data a mathematical model of plasticity is developed in the way of improvement of the nonlinear kinematic hardening model by introducing of an additional function of previously accumulated plastic strain. For better correlation with experimental results the Mises plasticity criterion written in the form of the Baltov and Sawczuk’s model was modified by intro-ducing of a function which is intended to describe decrease of the yield stress during plastic deforma-tion. In order to model a reduction of the young’s module at unloading stage of the cyclic tension-compression test a material damage parameter was introduced according to the effective stress concep-tion. Numerical simulation of the cyclic tension-compression testing which accompanied experimental investigation has shown good coincidence with experiment results.

Keywords:
the Bauschinger effect, material damage, tension-compression test, nonlinear kinematic hardening

Okorokov V.O. Experimental Determination of the Bauschinger Effect and Material Damage . NTU «KhPI» Bulletin: Series «Dynamics and Strength of Machines». 2014. No. 58. Pp. 141-153.

On the basis of the embedding method the solution of the nonstationary heat conduction problem in a three-dimensional formulation for laminated cylindrical shells of complex shape in the plane by heating the interlayer film heat source is received. The presented approach can be applied to canonical or noncanonical form of the shells. The five-layer cylindrical shell is considered. In the studied shell the heat source is located between fourth and fifth layers. On the outer surfaces and the side surface of the shell occurs convective heat transfer. The initial temperature of the shell and the ambient temperature are the same. A comparison with the results of the multilayer cylindrical shell thermographic study, which confirms the reliability of the results on the basis of the suggested approach, is performed. Com-parison in different times is given. The proposed approach can be applied in the design of laminated glazing of aircraft and other vehicles.

Keywords:
thermal conductivity, multilayer shell, complex shape, heat source, thermographic study

Shupikov A.N., Sviet Ye.V. Nonstationary problem of heat conduction in a three-dimensional formulation for laminated cylindrical shells of complex shape: Theory and Experiment. NTU «KhPI» Bulletin: Series «Dynamics and Strength of Machines». 2014. No. 58. Pp. 154-161.

Represented by scheme of a simulation model of the hydraulic tilting the cab truck. A simulation model is implemented in the system modeling of dynamic and event-driven processes Simulink system engineering and scientific calculations Matlab. Structural scheme of the simulation model reflects the sequence of energy transfer from the operator to the actuator for a given law input operator. A simula-tion model was developed in the form in blocks with functional relationships modeling workflows pump manually operated, fluid motion in the pipeline and workflows in the Executive cylinder and the movement of the cab around its point tilting. Represented by structural scheme models of the input signal, and the movements of the cab around its point tilting. The model input signal developed taking into account the experimental studies on natural samples, and the model the cab movements developed using Lagrange equation of the second kind, which takes into account a mass of moving parts, reduced to the cylinder rod. Modeling of dynamic processes the tilting mechanism cab performed for the motion of the cab to the zone of unstable equilibrium when the frequency of exposure lever to be 1 Hz and the subsequent movement of the cab until the stop under the action of gravity. The simulation results are presented as a graph with the help of which we can estimate the pres-sure in the working chamber of the pump cylinder and the cab tilting angle around the breaking point. The analysis of the dependence of the fluid pressure in the working chamber of a hand pump and hy-draulic cylinder cavity executive of cab tilt angle for harmonic input signal. The influence of the mass of the cab and tilt base tipping on the value of the manipulated variable. Also executed, the analysis of the energy parameters of the hydraulic cylinder under the influence of reduced load. Given the pros-pects for future research.

Keywords:
simulation model, dynamics, truck, cab tilt mechanism, pump, hydraulic cylinder

Shuklinov S.M., Zalohin M.Yu. Imitations study of dynamic processes the mechanism tilting cab truck . NTU «KhPI» Bulletin: Series «Dynamics and Strength of Machines». 2014. No. 58. Pp. 161-168.

In this paper a composite material with similar cross-ply fibers is considered. Assuming orthotropic structure, theory of elasticity is used for investigating the stress concentration. The effective characteristics of this composite are studied numerically by using ANSYS software. In this research a volume element of fibers in square array in the coordinate x, y, z and the generalized stress state is con-sidered. In order to investigate the numerical finite element modeling, the modeling of a quarter unit cell is considered. For determining the elasticity coefficients, stress analysis is performed for considered volume with noting to boundary conditions. Effective elasticity and mechanical properties of composite which polymer epoxy is considered as its matrix, are determined theoretically and also by the proposed method in this paper with finite element method. Numerical experiments modeled four cases of uniaxial tension in the directions x, z and shear in the planes xy, yz. Finally, the variations of mechanical proper-ties with respect to fiber-volume fraction are studied. Numerical results are compared with approximate estimates method proposed.

Keywords:
composite, cross-ply fibers, effective elastic constants, orthotropic

Darya zadeh S., Lvov G.I., Kiahosseini S.R. A new numerical method for determination of effective elastic constants in a composite with cross-ply fibers . NTU «KhPI» Bulletin: Series «Dynamics and Strength of Machines». 2014. No. 58. Pp. 169-180.