Shaft Support Research Articles

Investigation of friction noise in linear bushing by frequency domain analysis and theoretical model

Linear bushings, unlike existing bearings, are a system that enables linear movement of the axis. This has the advantage of allowing efficient motion due to low friction as it operates through the rotation of the ball, but has the problem of generating noise due to friction between the shaft and bushing. The purpose of this study is to identify the causes of friction noise by checking the frequencies contained in the bushing noise. To this end, a theoretical model is established by referring to conventional LM(Linear Motion) guide research that has similar behavior to bushings, and the reliability of the model is verified through experiments. To simulate actual driving situations, an experimental setup consisting of a fixed support shaft, motor, etc. is created and the noise of original and defective bushings is measured. Through this, commonly included frequencies are detected, and analyze how the frequencies change depending on faults.

Dynamic analysis of a propulsion shaft system considering the flexible coupling and motor isolations

This paper presents a dynamic model for the propulsion shaft system of an unmanned underwater vehicle. The model considers the effects of the flexible coupling and motor isolators. The motor bearings, shaft support bearings, thrust bearing and propeller are considered. A multi-degree of freedom isolation model for the motor stator is established. The coupling effects of shaft, motor bearings, shaft support bearings and motor excitation are considered. A finite element mode analysis and forced vibration experiment is conducted to provide the verification. The influences of the shaft speed, flexible coupling stiffness, motor isolation stiffness and installation position on the system vibrations are studied by using the numerical model. This study could provide some guidance for the dynamic analysis and vibration optimization of the propulsion shaft systems of UUVs.

Mechanical and Thermal Analysis of a Rocker Arm Shaft Support Based on Finite Element Method

Abstract The Finite Element Method (FEM) is a powerful numerical technique for solving complex physical problems involving differential equations and partial derivatives. This study presents the mechanical and thermal analysis of a rocker arm shaft support using FEM. Employing the ADINA (Automatic Dynamic Incremental Nonlinear Analysis) software, the behavior of the shaft support has been modelled, leveraging ADINA’s extensive material libraries, diverse loading conditions, and customizable behavioral properties. The analysis focuses on determining deformations, stresses, and displacements, particularly in the median plane section at the point of maximum stress. Both treated and untreated material conditions are evaluated to assess stress transmission in the transition zone between surface-hardened and base materials. A 2D analysis is conducted, given the geometry of the rocker arm spindle support, to ensure fidelity to real structural behavior while optimizing computational efficiency. The validated model provides insights into design constraints for new materials, supporting industrial applications.

Machine Learning Approach for LPRE Bearings Remaining Useful Life Estimation Based on Hidden Markov Models and Fatigue Modelling

Ball bearings are one of the most critical components of rotating machines. They ensure shaft support and friction reduction, thus their malfunctioning directly affects the machine’s performance. As a consequence, it is necessary to monitor the health conditions of such a component to avoid major degradations which could permanently damage the entire machine. In this context, HMS (Health Monitoring Systems) and PHM (Prognosis and Health Monitoring) methodologies propose a wide range of algorithms for bearing diagnosis and prognosis. The present article proposes an end-to-end PHM approach for ball bearing RUL (Remaining Useful Life) estimation. The proposed methodology is composed of three main steps: HI (Health Indicator) construction, bearing diagnosis and RUL estimation. The HI is obtained by processing non-stationary vibration data with the MODWPT (Maximum Overlap Discrete Wavelet Packet Transform). After that, a degradation profile is defined and coupled with crack initiation and crack propagation fatigue models. Lastly, a MB-HMM (Hidden Markov Model) is trained to capture the bearing degradation dynamics. This latter model is used to estimate the current degradation state as well as the RUL. The obtained results show good RUL prediction capabilities. In particular, the fatigue models allowed a reduction of the ML (Machine Learning) model size, improving the algorithms training phase.

Analysis of the stability of a novel assembled working shaft support structure during pipe jacking construction: Experiments and numerical simulations

Pipe jacking construction is a commonly employed trenchless technique for laying underground pipes in urban areas. However, the conventional support structure for pipe jacking shafts poses challenges, including difficulty in reserving pipe jacking holes, susceptibility to tilting, low bearing capacity, and the potential for failure during construction. Taking the 5# pipe jacking shaft of the pipe jacking construction for diverting the Yellow River through the river at Niukouyu in Zhengzhou City as the research background, investigates the soil settle deformation around the working shaft and the mechanical response law of the supporting structure during the short-distance, long-distance and second long-distance pipe jacking construction by combining the practical engineering field test and finite element numerical simulation, and carries out a sensitivity analysis on the main design parameters affecting the stability of the supporting structure through orthogonal test. The findings reveal that during the second pipe jacking construction, stress and deformation of the supporting structure are higher than those observed in the first pipe jacking. Notably, support piles and waist beams at the entrance of the pipe jacking experience greater force, and the back and side walls undergo increased force and deformation in the later stages of pipe jacking, and support pile spacing is the main control factor affecting the mechanical performance of the novel support structure. The study concludes that monitoring and protection measures should be reinforced, particularly in areas prone to failure and damage during construction. The insights gained from this research can serve as a reference for designing, optimizing, and safely monitoring novel assembled pipe jacking shaft support structures.

Vertical Axis Wind Turbine

The key components of a vertical-axis wind turbine (VAWT) are located at the base of the turbine, with the primary rotor shaft aligned transversely to the wind. Because of this arrangement, maintenance and repairs are made easier because the generator and gearbox are located close to the ground. The parts of a vertical axis wind turbine include the blade, shaft, bearing, frame, and blade support. In short, the rotor rotates because of the dynamic pressure exerted by the wind on the blades. Concurrently, the opposing side of the blades encounters aerodynamic hindrance, occasionally referred to as "drag." We experience something similar when we run or cycle: airflow is constantly working against us. Key Words: Turbine, Dynamic pressure, Rotar resistance, Shaft.

Multibody dynamic study and optimization for a flexible support shaft system in unmanned underwater vehicle

This paper presented a multibody dynamic model for the shaft system in an unmanned underwater vehicle (UUV), the model considers the flexible coupling, ball bearing and flexible support. The stiffness characteristics of flexible coupling are calculated by using the finite-element analysis. The effects of load condition, bearing location and support stiffness on shaft vibrations are investigated. Then, an optimization for the bearing locations and support stiffness is conducted. This study provides some guidance for the design and vibration optimization of the shaft system in UUVs.

Role of BicDR in bristle shaft construction and support of BicD functions.

Cell polarization requires asymmetric localization of numerous mRNAs, proteins and organelles. The movement of cargo towards the minus end of microtubules mostly depends on cytoplasmic dynein motors. In the dynein-dynactin-Bicaudal-D transport machinery, Bicaudal-D (BicD) links the cargo to the motor. Here, we focus on the role of Drosophila BicD-related (BicDR, CG32137) in the development of the long bristles. Together with BicD, it contributes to the organization and stability of the actin cytoskeleton in the not-yet-chitinized bristle shaft. BicD and BicDR also support the stable expression and distribution of Rab6 and Spn-F in the bristle shaft, including the distal tip localization of Spn-F, pointing to the role of microtubule-dependent vesicle trafficking for bristle construction. BicDR supports the function of BicD, and we discuss the hypothesis whereby BicDR might transport cargo more locally, with BicD transporting cargo over long distances, such as to the distal tip. We also identified embryonic proteins that interact with BicDR and appear to be BicDR cargo. For one of them, EF1γ (also known as eEF1γ), we show that the encoding gene EF1γ interacts with BicD and BicDR in the construction of the bristles.

Proper Orthogonal Decomposition-Based Surrogate Modeling Approximation for Aeroengines Nonlinear Unbalance Responses

Abstract Finite element (FE) models to simulate aeroengines rotordynamics become more and more complex thanks to the improvement of computational resources. Numerical simulations for industrial scale applications are nevertheless expensive in terms of computational effort because of their size and the presence of nonlinearities. In many-query frameworks (sensitivity or reliability analysis, model calibration, etc.), parametric studies have to be performed and the FE models are generally simplified or strongly reduced with a consequent loss of accuracy. Recent machine learning methods can be employed to build faster-to-evaluate surrogates of the original model. Nevertheless, this type of offline approach can be very demanding in terms of number of full order evaluations to reach a sufficient accuracy. The challenge is therefore to control the burden associated with the evaluation of the design of experiments (DoE) and the surrogate model training phase. This work presents a surrogate modeling technique to quickly and accurately reproduce the nonlinear unbalance responses of industrial scale rotor-dynamical models submitted to rotor–stator contact. About 20DOFs of the industrial FEM are considered in this work and a proper orthogonal decomposition (POD)-based approximation (surrogate modeling technique known as POD-SM or nonintrusive POD in the literature) of their frequency dependent unbalance response are presented. In order to analyze the modeling uncertainties of a specific shaft's support of a modern aeroengine, its dynamical parameters (stiffness, damping, nonlinear contact parameters) are studied within a specific variation range, defining the design space covered by this study.

Research on Structural Parameter Optimization and Springback Compensation Methods of a Steel Bar Hoop Bending Machine

After being processed into a certain shape by a stirrup bending machine, steel bars are used as the skeleton of reinforced concrete in construction. The accuracy of their bending directly affects the bearing capacity of reinforced concrete. In order to improve the accuracy of the springback angle of steel bars after bending, this paper focuses on optimizing the structural parameters of the steel bar bending machine and controlling the springback angle of steel bars. The influence of the support shaft diameter, bending crankshaft diameter, and bending crankshaft radius on the springback angle of steel bars is analyzed using ANSYS explicit dynamic simulation and experimental analysis. By combining orthogonal experimental methods, the bending structural parameters were optimized, including a support shaft diameter of 20 mm, a crankshaft bending diameter of 40 mm, and a crankshaft bending radius of 80 mm. This can effectively reduce the springback angle of the steel bars and improve the accuracy of the bending angle after bending. In addition, in order to improve the control accuracy of the steel bar springback angle, a cubic spline interpolation method was proposed, and the collected steel bar springback angle data were fitted using Matlab. At the same time, comparisons were made between the least squares method, polynomial interpolation method, and cubic spline interpolation method. The results show that the compensation formula obtained by using the cubic spline interpolation method can effectively improve the control accuracy of the steel bar bending springback angle.

A 3-D finite element modeling method for time-varying rotor-support system based on rotating-fixed coordinates

The asymmetry of rotor systems is sometimes evident, such as keyed shafts, crack rotors, two-pole generator rotors and especially shaft-disk-blade systems. Meanwhile, the coupling vibration problem between rotor and support structure is becoming more and more prominent due to the light weight of aero-engines. The design and analysis method for the dynamic characteristics of time-varying rotor-support system with detailed structure is needed. Therefore, a modeling method is proposed by using 3-D finite element for time-varying rotor-support system based on rotating-fixed coordinates. The rotor is modeled in rotating coordinate system and the support structure is modeled in fixed coordinate system respectively. The force, energy and displacement between rotor and support structure are transmitted by bearing mechanical parameters. Thus, the time-varying characteristics of the system are expressed explicitly by bearing mechanical parameters, and the dynamic equation of time-varying rotor-support system can be obtained. Then, Floquet theory and Hill infinite determinant method are used to analyze quasi-mode frequency characteristics and stability of time-varying rotor-support system. The results of a typical asymmetric rotor-support system got by the proposed method were compared with existed methods, and more coupling vibration characteristics such as the coupling vibration of rotor axial motion and support plate bending, the coupling vibration of shaft bending and support plate torsion were obtained.

Concerning the justification of the working characteristics and construction parameters of the bearing assembly of the upper support of the pellet furnace shafts

Problem. Metallurgical industry requires raw material for further steel production. One of the technological chain element is grid furnace, equipped with shafts, which hold the grid with raw product during heating. Insufficient cooling of the shafts provides the durability decrease and interruption of the technological process during the shafts’ failure. The article presents the results of research into the working conditions of the upper support shafts of the metallurgical furnace.
 Goal. The goal of the paper is to find the absolute thermal expansion of the shaft by means of thermal transient methods and identify the required bearing clearances to extend durability and reliability of the technological element. Results. Using the method of finite elements, the calculation of the thermal mode of operation of the part was carried out and the absolute values of thermal expansion under the condition of forced cooling were determined. Originality. Finite element analysis has been used to examine the necessity of bearing clearances correction as well as working regimes of steel construction. Practical value. To determine the cooling modes, experimental tests of the cooling system were carried out. Based on the results of working out the temperature modes of operation, attention is focused on the sufficiency of thermal clearances in bearing units and the operating modes of rolling bearings. In order to substantiate the working characteristics of the bearing assemblies, experimental studies of the effectiveness of the lubrication system and consistent grease were conducted.

Evaluation of Tractor Quality Based on Vibration Characteristics

Problem. The overall development time for agricultural tractors is 7-10 years, with testing accounting for approximately 63-80% of the total time. Within testing, reliability testing under operating conditions comprises 58-73% of the workload. However, even after extensive testing, serially produced tractors often fail to meet the specified lifespan and reliability requirements. Final refinements are only made to tractors after a certain accumulation of operational faults, resulting in hidden defects remaining in the serial production of tractors, as testing primarily addresses major structural and manufacturing defects. Goal. The aim of this study is to evaluate the design and manufacturing quality of tractors based on their vibration characteristics. These characteristics can identify structural and technological defects that decrease the reliability and lifespan of tractors. Methodology. Analytical research methods were employed to improve the quality of traction electric motors for electric transportation. Experimental research methods and the determination of electric motor technical conditions based on their vibrodiagnostic parameters were utilized. Statistical methods were employed to process experimental studies. Results. Vibration measurement results indicated that tractors belonging to vibration class E are not recommended for serial production. These tractors have an estimated lifespan of 6-8 thousand engine hours and incur high maintenance costs compared to tractors of vibration class D. Tractors with vibration levels of class E are not recommended for serial production due to the excessive vibration load on components. Originality. The T-150K tractor family requires significant redesign of its structure, manufacturing processes for components, and bearing unit assembly. This is achieved through constructive measures, such as ensuring bearing preload in shaft supports, using class 4 precision bearings with a noise index of QE1, and providing a floating fit with a clearance of no more than 15 μm between the bearing and the housing. Introducing intermediate bushings into the design of gearbox output shaft bearings improves the accuracy of machining bearing seating surfaces and the assembly of bearing units. Practical value. The developed vibration evaluation methods for T-150K tractors enable the assessment of their design and manufacturing quality. The research data obtained during the design stage allows for more reliable predictions of tractor quality.

Friction assessment of ultralow viscosity lubricant formulations based on a validated elastohydrodynamic simulation

High-performance engines are highly optimized machines; therefore, any identification of potential improvement requires a detailed study to assess different performance scenarios, working fluids and engine configurations. Simulation tools are among the best ways to study all possible options. In this framework, a validated elastohydrodynamic (EHD) simulation model of the connecting rod journal bearing is used to assess the performance of different lubricant formulations in mixed lubrication scenarios. To simulate a realistic scenario, a finite element analysis (FEA) is performed, where the assembly of connecting rod and shaft supports are modelled with finite element models (FEM) to account for elastic deformations on journal bearings. Furthermore, a set of oil properties is measured and collected to import into GT-Suite commercial software. This set enables us to consider the dependence of variables such as viscosity, density, specific heat transfer, and coefficient of friction on the shear rate, pressure, temperature, and air solution. Moreover, a friction assessment methodology is presented to choose the best lubricating oil for severe working conditions. This test method accounts for several factors: tribology, rheology, wear, and lubrication regime. The results are presented for three ultralow viscosity lubricants and the reference oil from validation. This assessment gives a complete comparison of lubricants performance, where lubrication regime and tribological losses are key factors to select the best candidate.

Features of structural assessment of long life mine shafts

The issues of restoration and reconstruction of mine shafts become of increasingly higher concern these days. Timely accomplishment and complex safety are the first-order conditions of the successful project implementation. The existing regulatory documents in this sphere are inexhaustive. In this respect, and integrated approach is proposed, including geophysical investigation of shaft siding areas, experimental estimation of load-bearing capacity of support systems, experimental computations using 3D finite element method, as well as the analysis and prediction of structural reliability. The authors exemplify implementation of the complex approach. The GRP measurements and seismic research in some shafts revealed long intervals of fractured rocks and damaged rock/lining interface zones, as well as local voids in the space behind the lining. These data were used to adjust mathematical models with the identification of local zones in the fractured shaft side rock mass with low deformation characteristics, and some series of calculations were performed. In the test area of a mine shaft, the calculations and the in-situ measurements of stresses and deformations agreed sufficiently. The authors highlight that the research-based data array enables better reasoned decision-making on design, construction and technology at integrated safety and enhanced efficiency of operations. Moreover, understanding of the actual condition of the shaft lining and adjacent rock mass can help avoid causeless repair which decreases load-bearing capacity of shaft support down to extreme values in the short run, and continually ends with incidents and large accidents in actual practice.

Failure analysis of auxiliary support bearing/shaft tribopair in seawater hydraulic axial piston pump

The auxiliary support structure is used to prevent the cylinder block from tilting in seawater hydraulic axial piston pump (SHAPP). The failure modes of auxiliary support bearing and shaft under different material combinations were compared. Experimental results show that improper design of radius fitting clearance in auxiliary support bearing/shaft tribopair will seriously affect the normal operation of SHAPP and even lead to its damage. Based on the inertia force, nonlinear water film force and dynamic load balance of the rotating cylinder block, the mathematical model of the nonlinear shaft centerline orbit of the auxiliary support bearing was established. The nonlinear shaft centerline orbit of auxiliary support bearing in the cylinder block bore during SHAPP operation is analyzed accurately. Simultaneously, the water film pressure field under different radius fitting clearance is simulated and the range of the optimal value is determined. The running-in experiment of SHAPP is carried out under the optimum clearance of the auxiliary support bearing/shaft tribopair. The results show that the SHAPP can run normally and the performance is obviously improved without the wear on the friction pair surfaces. Therefore, the proposed method has provided the guidance reference for the design of auxiliary support bearing in SHAPP.

ELASTIC EMBEDMENT SUPPORT: A NOVEL APPROACH TO THE PRELIMINARY DESIGN OF SHAFTS

This study discusses the introduction of elastic embedment support in the preliminary design of shafts. The preliminary design of shafts idealizes the supports by considering them mobile articulated support, fixed articulated support, or embedded support. In several cases, these idealizations deviate from reality. While articulated supports produce internal forces, tensions, deflections, and gradients greater than real, embedded supports lead to internal forces, stresses, deflections, and deformation angles lower than real. These deviations in typical shaft design schemes have been corrected with safety factors. This study presents a novel elastic embedment support using a dimensionless stiffness coefficient to improve the preliminary shaft design and obtain more adequate results, with shaft dimensions more suitable for the acting loads. These results were assessed with the conventional analysis schemes for three bearing types for shaft lengths between 200 to 1000 mm. Contrasted to the conventional model articulating both shaft supports, the bending moment is significantly lower when considering the elastic embedment. The maximum bending moment from the conventional model is 65% higher than that obtained with the elastic embedment for single-row ball bearings, 58% higher for tapered roller bearings, and 40% higher for double-row ball bearings. Furthermore, the bending moment increases its significance with the shaft length. Thus, considering the bearing stiffness for the three rolling bearing types results in shaft support bending moments of 10 to 21% of the maximum bending moment obtained from the conventional model. These differences significantly impact the fatigue life estimation of the shaft because the deflection obtained from the conventional model is higher than that for the elastic embedded support, which impacts the fatigue life estimation of the shaft. Therefore, it is concluded that using the elastic embedment support in the preliminary shaft design, reduces the uncertainty in the results, leading to lower security coefficients. Keywords: Preliminary Shaft Design, Embedded Support, Articulated Support DOI： https://doi.org/10.35741/issn.0258-2724.58.1.47

Analysis of the amplitude of vertical oscillations of the main shaft on a sewing machine

The article provides a mathematical model of the vertical oscillations of the main shaft on the elastic supports of the sewing machine, taking into account inertial forces, as well as the rigidity characteristics of the rubber shaft supports. The regularities of the main shaft designs are experimentally determined for various modes of grinding materials. An effective design scheme of bearing supports with rubber shock absorbers of the main shaft of a sewing machine has been developed and recommended.

Удосконалення технології розбирання металоконструкцій механізованого шахтного кріплення

During operation, the hinge connections of mine supports practically stop rotating. This is due to the fact that, as a result of the aggressive mine water and strong dustiness, the diametrical clearance of 1-2 mm between the axis and the bushing is tightly filled with oxides and coal dust, especially in the connections of the base. This circumstance leads to the fact that the axes (pins) in the hinges lose their mobility and require significant effort for their dismantling. To repair the mechanized mine support, it is necessary to dismantle the hinge connections, which are formed by axes and holes in levers (traverses), base ears, and overlaps. Currently, the dismantling of hinge connections of mine supports is carried out using manual impact tools. This operation is extremely labor-intensive, physically heavy, and belongs to hazardous work. The goal of the study is to improve the working conditions of the operator during the dismantling process of axes in hinge connections of mine supports by using a mechanized specialized hydraulic press. To achieve the set goal, the following tasks must be solved: to determine the maximum permissible disassembly force of the axes, taking into account the strength of the load-bearing structure elements; to develop a concept of a mechanized hydraulic press, including the composition of the installation, the general technical description, the principle of operation, the kinematic scheme, and the tool. Studies have been carried out on the deformation modeling of mine support elements under load using the SOLIDWORKS Simulation calculation module to determine the maximum permissible disassembly force of the axes. It has been shown that the disassembly load of the shaft support axis with a force of more than 1000 kN leads to the loss of the structural strength reserve, which is unacceptable. An effective technology for dismantling the axes of a mechanized mine support has been proposed. A concept of an original specialized hydraulic press "Kit-100" for dismantling axes has been developed, which allows replacing the physically heavy and dangerous work of the operator with a lighter, mechanized process.

Dynotest Design Analysis for Electrical Converted Vehicles

The study comprises dynotest design and analysis to measure torque and horsepower. Basically, a dynotest carried out by apply certain load to the axle of a combustion motor through the braking mechanism of its crankshaft. Due to the high price of a Dynotest unit in the market, it is relatively difficult for a developing institution to own it on their site. The study target to design a simple and good accurate Dynotest within a reasonable price. The study used a common standard method for design analysis which rely on function and structural approach. Functionally, Dynotest is designed to be used to an ouput of an electical motor. Loading on motor shaft was done by disc brake braking mechanism. Structurally, Dynotest was designed to use rollers. As a main component, its mounting construction is connected to a motor to generate electrical power. Power transmitted from the motor to Dynotest through a center joint shaft, torque measured by load cell while the rotation of shaft itself counted by a digital tachometer. Test result show that electricity was produced from the simple construction and Dynotest functioned well in measuring it. Measurement data of roller support shaft performance showed a motor torque performance curve which are similar with the typical of similar Dynotest. Construction Test done by applying Solid Work software analysis to some components partially on rollers and on the construction assembly as a whole unit