Bearing Element Research Articles

Evaluation of Tangent Bearing Element Axial Load Response

Augered cast-in-place (ACIP) piles, also known as continuous flight auger (CFA) or augered pressure-grouted (AGP) piles, are a well-established method for installation of deep foundation elements. A current equipment constraint of ACIP piles is the largest practical diameter that can be constructed. To overcome this limitation, some ACIP contractors have begun offering deep foundations which in this paper will be referred to as Tangent Bearing Elements (TBEs). A TBE consists of two or more ACIP piles spaced at one diameter center-to-center. The individual pile elements form a bundle which acts as a single foundation element in axial loading. This results in an efficient foundation installation method which produces equivalent-sized elements faster than traditional large-diameter bored piles. Because of their non-traditional geometry however, design engineers may be hesitant to utilize TBEs. This paper examines the results of several bi-directional static load test programs conducted on TBEs.

Pipe pile with internal diaphragm as effective bearing element of deep-water structures

One of the ways to reduce piling expenses is decreasing volume of piling works. It can be provided by shortening either the piles length or the number of pipes. These results may be achieved if each short-cut pile is improved and bears the same loading as a pile of normal length or if each pile of normal length is improved and bears larger axial force in comparison with its initially designed capacity. Presented study clarified possibilities to regulate the pipe pile’s bearing capacity using an internal rigid diaphragm (closure) placed inside the pile’s shaft. It increases the bearing capacity of the tubular pile due to additional soil reaction under the closure. Pressing the pipe pile’s model into sand box was assumed as the most gentle and precise method to study considered driving process. Besides results of such approach may be good adapted to predict pipe behavior in case of Press-in method of the pile installation. Some conclusions were made clarifying the diaphragm’s positive contribution to pile bearing capacity, the effect of the closure’s location along the pipe shaft, and the influence of the diaphragm’s design (flat, conical, and cylindrical closures). Numerical analysis of the gained experimental data gave the possibility to apply approximating functions with good correlation indexes

A data-driven exploration of multi pad bidirectional adjustable bearings and deep learning model-based optimization

The evolution of journal bearings, from fixed profiles to adaptive configurations, signifies a captivating progression in journal bearing technology. A notable innovation in adaptive bearings is Multi-pad Bidirectional Adjustable Bearing (MBAB), which can control film thickness in radial and circumferential directions. This paper introduces a novel data-driven approach, utilizing machine learning to model and optimize the static performance of MBABs with asymmetric bearing element adjustments. The study uses a parameter-independent Jaya algorithm coupled with machine learning models to identify optimal combinations of adjustments. Results highlight the significance of negative radial adjustments and asymmetric profiles for optimal performance. This research contributes to Industry 4.0 by bridging the physical-digital gap, offering a data-driven solution to enhance the performance of these advanced bearings.

Виброактивность электромеханических устройств вследствие наличия технологических погрешностей

This article discusses a theoretical justification for the presence of vibration in operating modes of electromechanical devices due to technological errors occurring during the machining of parts and assembly of products. The reason for the presence of a dense spectrum of vibration caused by technological errors in the structural elements of ball bearings (outer and inner rings, balls, and cage) is also denoted. The analytical dependence of the vibration amplitude on the magnitude of technological errors is shown. It follows from the results of the analysis that for the most effective minimization of the vibration activity of an electromechanical device, it is necessary to use broadband damping, which is liquid–viscous in most cases. In addition to the above, it is advisable to apply damping in the cascade version. When solving the system of vibration equations for an electromechanical device, replacing ball bearings with sliding bearings eliminates the first four terms, which characterize a wide and dense vibration spectrum of the ball bearings in the operating mode of the electromechanical device.

Bearing Fault Classification Using Multi-Class Machine Learning (ML) Techniques

Bearing elements are widely used in rotating machines and their failure results in a considerable amount of downtime of the machines. The aim of this work is to classify defects in a bearing. Three types of classification have been done: (i) Binary classification: classification as non-defective or defective bearing, (ii) 3-class classification such as non-defective, defective with inner ring defect and defective with roller defect and finally (iii) 7-class classification corresponding to no defect condition, three ring defect conditions pertaining to indentations of three different sizes on the inner ring and three roller defect conditions corresponding to indentations of three different sizes on the roller. The open-access data generated using a rolling bearing test rig from the Politecnico Di Torino, Italy, has been used for this work. The data had been obtained using 2 accelerometers on two bearing housings for multiple load and speed combinations. For classification, in the present work, classical ML algorithms such as logistic regression (LR), K-Nearest Neighbour (K-NN) classification algorithm, random forest (RF), support vector classifier (SVC) and kernel support vector machine (KSVM) have been used. All these techniques gave very promising results, the classification accuracy varying from 0.7969 to 0.9996 for all speed-load conditions. Such classification work across multiple operational conditions, with multiple fault conditions and multiple signatures with faulty components, has not been reported.

Technology of calibrated wire production for bearing rolling elements manufacturing

The article considers technological schemes of cold‑formed wire production for bearing rolling elements production. Several technological schemes of wire production are considered. The paper presents a step‑by‑step development of drawing technology of alloyed (chromium) bearing steel grade. Problems arising at drawing of bearing steels are described. The reason of formation of “flaking” on the surface of rod is revealed. Ways of solving the problem of unsatisfactory drawing of wire from bearing steel grades are stated.Relevance and novelty of technical and technological solutions of the present work are caused by the absence of production of calibrated wire for manufacturing of rolling elements of bearings on the territory of the Republic of Belarus. The development of this type of production will allow to increase the production of high‑tech products with a deep degree of processing (calibrated wire) for the growth of profitability and efficiency indicators. Creation of production of calibrated wire for manufacturing of rolling elements of bearings will allow to reach new consumers of metal products with increase of added value of finished products.

Modelling and Simulation of Aerodynamic Cylindrical Bearings Using ANSYS Hydrodynamic Bearing Element Types

Modern power engine concepts and environmental restrictions demand oil-free lubrication of rotors, for example, by gas bearings. However, the stiffness and damping properties ruling the rotor’s dynamics are poorly documented for aerodynamic bearings and simple calculation methods are lacking. Based on the similarity between aerodynamic and hydrodynamic journal bearings, it is investigated to what extent the hydrodynamic bearing element types of the commercial FE program ANSYS are also suitable for air bearings. Within these elements, the compressibility of the gas is neglected. After verification of the ANSYS hydrodynamic element types with literature data for cylindrical hydrodynamic bearings, the stiffness and damping coefficients of a cylindrical aerodynamic bearing are calculated by using the ANSYS hydrodynamic element types. In the examined speed range, the results agree well with literature data that consider gas compressibility. Therefore, the FE elements designed for hydrodynamical journal bearings may also be used for simulating cylindrical aerodynamic bearings. The presented calculation approach provides a compact and easy-to-use method for rotordynamic simulations with cylindrical aerodynamic bearings in a single development environment.

Material Characterization of Elastomeric Bearing Elements in Wave Energy Converters

According to the European Council, 75% of the greenhouse emissions are caused by energy production and use. In order to decarbonize the energy sector, more research is focused towards the renewable energy sources. Among the many available resources, wave energy is one of the key resources to consider. As part of the research, KTH is developing a winch based point absorber wave energy converter. The winch consists of a chain link with elastomer bearings wound around a drum. The winding and unwinding motion of chain converts wave motion into electricity. A typical winch based wave energy converter undergoes around 80 million cycles in its lifetime. This calls for a durable system design requiring minimal service and maintenance. With an elastomer bearing, the winding and unwinding of the chain over the drum is realized as deformation of the elastomer thereby eliminating sliding. While the use of elastomer enables an efficient design, it also makes it more challenging due to its highly non-linear and viscoelastic behavior. A constitutive model is necessary to determine material characteristics of an elastomer for different loading conditions. In this work, a systematic design process is outlined and an attempt is made to determine a suitable hyperelastic material model for the elastomer. The study is focused on two materials – silicone and polyurethane. The test samples are compressed and followed by shear in deformation. For material model determination, the test data is curve fit and later verified using finite element method. The material is assumed incompressible.

Seismic Performance of SFRC Shear Walls with Window Opening and the Substitution Effect for Steel Bars

Shear walls are important vertical and lateral bearing element in structures. While shear walls with openings are fragile due to stress concentration and the quasi-brittle behavior of concrete in tension. Therefore, additional strengthening rebars are required for the shear walls with openings. However, it aggravates the problem of dense reinforcement which increases the steel cage manufacturing and concrete compaction problem and still lacks countermeasures against concrete damage and cracking. To reduce the rebar demand and improve the damage tolerance of squat reinforced concrete (RC) shear walls with openings, an optimized steel-fiber-reinforced concrete (SFRC) was adopted to understand the seismic performance by cyclical loading test. The tested specimens included a plain RC shear wall without strengthening bar around the opening (for comparison), an SFRC shear wall, and an SFRC shear wall with a reduced distributed steel bar. This paper mainly studies the effect of using SFRC to improve the seismic performance of the open shear wall and to replace the reinforcement around the opening and the shear reinforcement. The hysteresis curves, skeleton curves, stiffness degradation, bearing capacity degradation and energy dissipation of the specimens were analyzed. The results show that the failure can be delayed and relieved, the deformation capacity and energy dissipation can considerably improve, and rebars can be partially replaced by using SFRC.

Study of Tribological Properties of Bulk Nanostructured Aluminum and Copper Samples Applicable in Automotive Bearing Application

Using lightweight systems and friction reduction approaches are two main contributors towards modern and efficient powertrains in the automotive industry. New materials and processes are required to achieve the demanding and ever-increasing performance requirement of automotive systems. Nanostructure induced by severe plastic deformation methods involves bimodal microstructures and hence, shows exceptional mechanical characteristics which can be exploited for automotive application. Through this study, samples were prepared using pure copper, aluminum alloy (series 7000) and were processed to attain bulk nanostructured samples using a Single Step High Pressure Torsion technique with appropriate dimensions applicable as the rolling elements of automotive bearings. The induced nanostructures resulted micro hardness and frictional characteristics of the bulk samples were assessed using transmission electron (TEM) and atomic force (AFM) microscopies as well as microhardness evaluations. The results revealed that a fully refined nanostructured samples were achieved with 90% increase in the hardness at the outer diameter of the sample. The AFM measurements indicated that the friction coefficient of nanostructured copper and aluminum samples were ~ 25 and ~ 45% less than that of both the unprocessed samples, respectively. Characteristics of treated samples suggest that these processes can be potentially used in demanding conditions of rolling element bearings with reduced weight and frictional losses.

Test Study of the Bridge Cable Corrosion Protection Mechanism Based on Impressed Current Cathodic Protection

The cable system is an important bearing element of a bridge with stay cables or slings and a matter of major concern in the safety of the bridge structure. Bridge cables are vulnerable to corrosion induced by leakage and soaking during their service life. To solve this problem, and based on the idea of proactive control by means of the impressed current cathodic protection (ICCP) of bridge cables, this study designs and develops an ICCP system device for bridge cable protection. In this study, an accelerated corrosion test was conducted to test the ICCP system of steel wires inside the cables and the cables under acid rain conditions. The corrosion protection behavior of ICCP was analyzed to reveal the corrosion protection mechanism of bridge cable ICCP. The results show that in the cable ICCP system, the impressed current generated by a more negative voltage may improve the efficiency of corrosion protection, but an excessively negative voltage may cause hydrogen embrittlement of the cable steel wire due to overprotection. The rational range of −1.13 V to −1.15 V was set as the result of the overall consideration. Within this range, the cable is subject to the joint protection of ICCP and sacrificial anode cathodic protection (SACP). Corrosive products can delay the development of cable corrosion to a certain degree; the SACP protection efficiency of the galvanized coat reduces gradually with corrosion development; and cable ICCP protection efficiency increases gradually. The ICCP for cable corrosion protection is transformed from joint protection using both a sacrificial anode and impressed current into protection, mainly using an impressed current.

Deformation parameters of high-strength steel fiber concrete under long-term load application

This article contain an experimental study of the rheological characteristics of high-strength steel fiber concrete (SFRC) that is used for the manufacture of permanent formwork. Permanent SFRC formwork is used in the construction of reinforced concrete structures of new generation nuclear power plants (NPP), where due to improved physical and mechanical characteristics it is used as a load bearing element. As a result, a structure with combined reinforcement is obtained, requiring improvement of existing calculation methods, including continuously acting load. The use of existing models of concrete behavior under conditions of continuous loading using SFRC is limited and requires experimental refinement. Studies in the field of nonlinear creep, where, according to a number of studies, the use of steel fibers is most effective are of a particular interest. The high labor intensity and duration of creep tests limited the research to two compositions of SFRC recommended for the manufacture of formwork and fine-grained matrix. Based on the established rheological characteristics at loading levels 0.3, 0.8, 0.85 and 0.9, analytical dependences that allow predicting the values of creep strain at different loading levels are obtained. The presented dependences are recommended for the calculation of reinforced concrete structures with non-removable formwork made of SFRC under a long-term load.

A generalized method for numerical modeling of seismically resilient friction dampers using flat slider bearing element

There has been a growing interest in recent years by both researchers and industry in developing friction dampers that have enhanced seismic performance by using inclined friction interfaces (i.e., not colinear with the plane of loading) in combination with a re-centering mechanism such as steel disc springs and/or SMA materials. These friction and friction-hybrid dampers provide both energy dissipation and self-centering characteristics. Compared to conventional flat-slider friction dampers (where friction interface is colinear with the plane of loading), numerical modeling of these types of friction devices is not straightforward and requires unique material models or complex element configurations to predict earthquake building responses. This technical note provides a generalized numerical model implemented in the OpenSees structural analyses framework that could be broadly applied to the numerical modeling of seismically resilient type friction dampers. The modeling scheme presented in this study utilizes readily available elements (i.e., flat-slider bearing element), eliminating the need and complexity of creating new material models. Given the increased interest found in the literature in the development of friction dampers with re-centering characteristics, this technical note could be useful for both researchers and engineers. Illustrative examples using two distinctly different seismically resilient friction dampers are presented for validation of the proposed modeling scheme. The first comparison is made with a cross-laminated timber rocking wall detailed with a newly proposed Uplift Friction Damper (UFD). Comparisons are made with both quasi-static cyclic tests and a continuum finite element numerical model in the ABAQUS software program. The second validation example compares results with a quasi-static uniaxial cyclic test of a Friction Spring Damper (FSD) device. Predictions of the proposed generalized numerical model are in good agreement with the results of both validation examples.

Further Investigations and Parametric Analysis of Microstructural Alterations under Rolling Contact Fatigue.

Bearing elements under rolling contact fatigue (RCF) exhibit microstructural features, known as white etching bands (WEBs) and dark etching regions (DERs). The formation mechanism of these microstructural features has been questionable and therefore warranted this study to gain further understanding. Current research describes mechanistic investigations of standard AISI 52100 bearing steel balls subjected to RCF testing under tempering conditions. Subsurface analyses of RCF-tested samples at tempering conditions have indicated that the microstructural alterations are progressed with subsurface yielding and primarily dominated by thermal tempering. Furthermore, bearing balls are subjected to static load tests in order to evaluate the effect of lattice deformation. It is suggested from the comparative analyses that a complete rolling sequence with non-proportional stress history is essential for the initiation and progression of WEBs, supported by the combination of carbon flux, assisted by dislocation and thermally activated carbon diffusion. These novel findings will lead to developing a contemporary and new-fangled prognostic model applied to microstructural alterations.

A novel approach to investigate the mechanical properties of the material for bridge health monitoring using convolutional neural network

In the bridge structure, the main bearing element is the spans, which are directly subject to random and continuous loads, environmental influences, ageing, etc. These factors are easy to lead to material deterioration. Therefore, this study proposes a novel approach to investigate the mechanical properties of the material. The span of the bridge is the selected structure for investigation. This study focuses on the general evaluation of mechanical factors consistent with reality, so the following main factors are to be carried out. First, the viscoelastic model of material will be applied to set up and solve the governing differential equation of the beams with material characteristics involving the elastic modulus (E) and the viscous coefficient (C). The viscoelastic model is different from the traditional elastic model due to its non-linearity, reflecting the actual state of the structure. Second, the random vibration signal-based Loss Factor function (LF) calculation using the Power Spectral Density (PSD) to detect changes in structures. LF is a feature representing changes in material properties, including elasticity and viscosity, and is suitable for many types of bridge structures. Also, the paper uses Cubic Interpolation (CI) to generate a surface representing the LF distribution. This interpolation results in surfaces with respect to the LF values distributed by frequencies and spectral amplitudes. Finally, the LF distribution-based material investigation using Convolutional Neural Network (CNN) is proposed with high performance and accuracy. This study applies the proposed method to several bridges in Ho Chi Minh City, Vietnam. It demonstrates that LF is highly suitable for bridge health monitoring.

Experimental Investigation of the Performance of SBR and RSS Materials as a Sliding Bearing Element

Conventional bearing systems and materials, which are important components of machine elements, have often failed to fulfil requirements, especially in places where sealing is required. In such cases, sliding bearings with PTFE- and NBR-based polymer and elastomer materials operating in water or oil are preferred. In this study, the performance of two alternative rubber-based materials, synthetic styrene butadiene rubber (SBR) and natural rubber smoked sheet (RSS), as a sliding bearing was experimentally investigated in terms of frictional resistance using pin-on-disc and pin-on-cylinder devices. In the study, very low friction forces emerged at low sliding speeds compared to PTFE and NR operating in water. The friction force values and friction coefficients obtained are presented in diagrams and tables.

Investigation of an Inline Inspection Method for the Examination of Cylinder-like Specular Surfaces Using Deflectometry

An optical measuring method is presented, with which it is possible to measure and evaluate reflective cylindrical surfaces using a combination of deflectometry and subsequent reconstruction of the surface. The system is set up and tested on rolling elements of cylindrical roller bearings. However, it is not limited to this use case and can be applied to other cylindrical specular surfaces. The system distinguishes itself from existing test methods through the combination of high-resolution three-dimensional defect measurement with a very short recording time, and offers the possibility of introducing tolerance limits in the production of cylindrical specular surfaces. With this method, it is possible to record a defect with the dimensions of 1.3mm by 1.8mm within 5 s and to reconstruct the absolute depth. The resolution of the system is below 10 μm in both X- and Y-direction, and is therefore sufficiently accurate to detect typical surface defects such as scratches, dents, or deformations. To validate the measured values of the system, the results of an artificially generated 10.35 μm deep defect location were compared with those of a highly accurate mechanical stylus measurement.

Analysis of Technological Heredity in the Production of Rolling Bearing Rings Made of AISI 52100 Steel Based on Waviness Measurements.

The production of rolling bearings is a complicated process that requires the use of many operations. The manufactured elements of rolling bearings should be of high quality while minimizing production costs. Despite many research studies related to the analysis of technological processes, there is still a lack of research and tools allowing us to satisfactorily assess the relationships between individual operations of the rolling bearing ring process of production and the quality. To perform such an assessment, one can use the concept of technological heredity phenomenon analysis. As the surface waviness of the bearing race is of key importance, the present paper aims at evaluating how the individual technological operations of the rolling bearing ring production process affect the formation of their surface waviness. The surface waviness of the bearing race was measured in both directions (two sections), i.e., along the circumference using the Talyrond 365 measurement system and across the circumference of the race using Talysurf PGI. The production of 6308-2z rolling bearings made of AISI (American Iron and Steel Institute) 52100 bearing steel was analyzed. The occurrence of the phenomenon of technological heredity in the production of rolling bearings was observed. The research results indicate that the turning operation reduces the surface waviness of the bearing rings obtained after forging, while the heat treatment causes a slight increase in surface waviness. On the other hand, grinding operation significantly reduces the waviness, with this reduction being greater for the outer ring. Furthermore, the research has shown that the waviness of the surface is an inheritance factor caused by individual operations of the rolling bearing rings manufacturing process.

Experimental study of drawing steel square boxes according to the circle-square scheme in radial and conical matrices

Modern economic conditions impose certain requirements on the functioning of all sectors of the national economy to reduce material consumption and save resources, including mechanical engineering, and one of its largest areas is stamping production, which involves the active development of advanced technologies, the creation of high-performance and flexible equipment and the use of new materials and blanks. One of the most common shaping operations of sheet stamping is the drawing operation, which is widely used in the production of parts in mechanical engineering (lids, tanks, crankcases), electrical engineering (housings of electrical panels, panels for mounting electrical equipment), automotive industry (lids, housings, pallets), instrumentation, watchmaking industry, as well as in medicine (manufacturing of sterilizers, autoclaves), light and food industry (parts of refrigerators, washing machines, gas stoves, etc.), rocket and space technology (parts of aircraft, bottoms of tanks of spherical and torus shapes, structure elements of plain bearings for helicopters and aircraft), etc.

INFLUENCE OF POSITION ERRORS ON THE STABILITY OF A LOADBEARING VERTICAL ROD OF GREAT FLEXIBILITY

Many building structures are considered as rod systems. Bearing elements of rod systems are under load and experience large stresses and deformations. When external loads increase, these stresses and strains also increase. There may come a point where some elements lack strength, stiffness or stability. Such cases may arise due to uneven settlement and roll of the structure in conjunction with errors in the manufacture and installation of structures, insufficient development of projects, etc. One of the main measures for the timely prevention of emergency situations is the properly organized monitoring of the stress-strain state of the elements. In this paper, we consider a model of stressed structure, which combines elements in the form of flexible deformable rods and elements acting on them, represented by force vectors. As an example, we consider a structure of two vertical rectilinear rods pointing along one plumb line and connected in a node. The lower rod is pinched in the base and is a load bearing element. The upper rod is an external load for the lower one and is represented by the equivalent force vector. In theory, the lines of action of forces lie on one vertical line, so there are no other forces and moments besides axial longitudinal forces; the forces are applied at one point with given coordinates. When constructing the rod system, each rod must be set to a given design position. There will be position errors of the elements during the installation phase of the structure. Position errors are generally represented by errors in the specified angles of inclination of the rods and errors in the position of the ends of the rods in the assembly. In a stressed structure, these errors are equivalent to the errors of the force vectors. A modified system of force vectors arises. In such a system, due to position errors, a horizontal force arises which has the main influence on the stability of the supporting flexible rod when the external load increases.