Vol 9, No 3-4 (2015)
- Year: 2015
- Articles: 13
- URL: https://journals.eco-vector.com/2074-0530/issue/view/3722
Articles
Optimal structural design of compressor stage
Abstract
Optimal structural design of compressor stage of aviation engine is considered. Structural optimization takes into account the blade shape and disk design. Minimization of mismatching between the blade shape in operating position and predefined aerodynamic blade shape and natural frequency detuning problem are discussed. Disk and joint weight minimization under certain constraints is investigated. Optimization criteria, constraints, parameterization and design models, design parameters are discussed. All results were obtained using finite element analysis program connected with the sequential quadratic programming (SQP) optimization procedure.
Izvestiya MGTU MAMI. 2015;9(3-4):5-15
5-15
Definition of optimum parameters of workpieces and superplastic forming and isothermal stamping operations for the manufacturing of thin-walled details of gas-turbine engines
Abstract
The technique of mathematical simulation of isothermal stamping and superplastic molding for determination of optimum parameters of work pieces and manufacturing operations is presented. Application of the technique for thinwalled case and hollow vane manufacturing are shown.
Izvestiya MGTU MAMI. 2015;9(3-4):16-25
16-25
Analysis of Geared Turbofan Engine Transmission on Operational and Breakdown Overloads
Abstract
Investigation of double-circuit geared turbofan engine (GTF) transmission dynamics for flight cycle loads was carried out. Flight cycle loads taking into account overloads at evolutions. Comparative analysis for response of engine models without load reduction device and with load reduction device fracture on fan blade fracture is performed. As basic GTF assembly the assembly presented in most of opensources is taken. For investigation the beam and solid models were developed. Both models contain of fan rotor, gear and low pressure rotor. Special finite element are used in beam model for simulation of stiffness characteristics of complex geometry rotor elements. Stiffness characteristics of beam model are verified with assistance of solid model.
Izvestiya MGTU MAMI. 2015;9(3-4):26-37
26-37
Application of the method of wave dynamic compliances to multi-disk rotors calculation
Abstract
A problem of calculation of multi-disk rotors resonance oscillations based on the method of wave dynamic compliances is considered. The approach allows selecting, from big variety of rotor natural modes, the ones, most important for practice, which can be induced by pulsations or hoop non-uniformity of a flow. A clear pattern of dynamic interaction of wheels for the set excitation may be received. The method application to resonance oscillations design of a real two-disk rotor is displayed.
Izvestiya MGTU MAMI. 2015;9(3-4):38-45
38-45
Gas-turbine engine secondary air system analysis
Abstract
Secondary air system model based on graph theory and one dimentional hydraulic models is discussed. Channel inclination to major axis of integration is taking into account. New hydraulic channel model for smooth transition between “horizontal” and “vertical” flow passages is proposed. Commercial software for 2D and 3D flow modeling were used for one dimentional models verification.
Izvestiya MGTU MAMI. 2015;9(3-4):46-54
46-54
Non-contacting finger seal dynamic model
Abstract
Dynamic response of the finger seal compliant elements to rotor motion is investigated. It is shown that radial adjustment of the fingers with respect to rotor surface displacements requires convergent (in rotor rotation direction) operating clearance under the pads. Due to arising gasdynamic lifting force appropriate seal gasdynamic balancing and non-contacting operating mode can be achieved. The results are numerically obtained on the basis of the aeroelastic dynamics analysis.
Izvestiya MGTU MAMI. 2015;9(3-4):55-65
55-65
Model of oil flow in long journal bearing in field of centrifugal forces
Abstract
Mathematical model of long journal bearing with incompressible oil flow in field of centrifugal inertia forces acting in lubrication layer of planet wheel journal bearing is developed. Modification of Reynolds equation based on Navier-Stokes equations is received, taking into account centrifugal forces’ impact on fluid film in oil gap of journal bearing. Model was verified by commercial software, which uses full Navier-Stokes equations. Results of verification shows considerable contribution of centrifugal inertia forces on total pressure distribution in journal bearing, carrying force and attitude angle.
Izvestiya MGTU MAMI. 2015;9(3-4):66-77
66-77
Application of the analytical functions theory for exact calculations of gear teeth stress
Abstract
Unlike a method of finite elements the method of complex analytical functions (МCAF) considered in article allows to divide computing procedures on two parts. The first part does not contain the description of the form of boundary elements and is calculated analytically. The second part includes the description of borders of area and is calculated numerically. In machine elements the first part has the greatest influence on accuracy of stress calculation, because МCAF method allows to carry out exact calculations. Results of calculations in the form of the graphs convenient for calculations of gears are presented.
Izvestiya MGTU MAMI. 2015;9(3-4):78-83
78-83
Dynamic analysis of gear pair
Abstract
The results of using the finite element method to calculate the dynamic stresses in gears are presented. The numerical simulation of meshing gears of different types is obtained a detailed breakdown of contact and bending stresses, rigidity of the mesh stiffness function depending for engagement phase, static and dynamic transmission errors. The behavior of the transmission having defects, namely, incipient cracks at the tooth root is analyzed. The results can be used to develop diagnostic signs transmissions to ensure responsible operation of technical articles.
Izvestiya MGTU MAMI. 2015;9(3-4):84-93
84-93
Dynamic model of GTE bevel drive
Abstract
A dynamic model of coupled torsional-bending oscillations of bevel drive is developed. By method of principal coordinates bending oscillations of bevel gear rim represented as superposition of natural forms. A frequency response of system by torque dynamic component, axial displacement and equivalent stress in gear rim are calculated. A correlation between different parameters of system’s oscillations is calculated. Resonance frequencies obtained by frequency response are compared with natural frequencies of isolated torsional and bending systems. Influence of gear profile modification on frequency response by dynamic transmission error and dynamic stresses in gear rim is studied.
Izvestiya MGTU MAMI. 2015;9(3-4):94-105
94-105
Determining of parameters of nonisothermal cyclic curve model
Abstract
It was proposed methodology of determining parameters of model of nonisothermal cyclic stress-strain curve. Algorithm of pattern recognition was implemented. It was based on minimization of function of mismatch between experimental results and calculation of three-parameter model curve which depends on Bauchinger’s effect, elastic unloading modulus and scale of transformation of nonlinear part of stress-strain curve. Odkvist’s parameter was used for measure of plastic deformation. Simulation of cyclic stress strain curve was carried out. Results of simulation were compared with experimental data.
Izvestiya MGTU MAMI. 2015;9(3-4):106-113
106-113
Supplementary stress method convergence rate acceleration
Abstract
Efficiency of supplementary stress method convergence rate acceleration by Aitken δ 2-method is shown using BEM for beam elastoplastic torsion problem solution as example. Aitken method with two iteration before relaxation and Aitken method with relaxation in each iteration step convergence rates were studied numerically.
Izvestiya MGTU MAMI. 2015;9(3-4):114-122
114-122
Analysis of variants of Cholesky method for solution of big sparse systems of linear algebraic equations
Abstract
Algorithms of solution of big sparse systems of linear algebraic equations based on Cholesky technique is released in program complex of analysis of stress-strain condition under cyclic elastoplastic loading by finite element method. Comparison of memory and computational resource efficiency of algorithms is carried out.
Izvestiya MGTU MAMI. 2015;9(3-4):114-132
114-132