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The detailed evaluation of the accumulated geological-geophysical data, particularly on the inner structure of the saltbearing series in the margins of the Caspian Depression, the mechanism of salt-tectogenesis manifestation, its reflection in the structure of the salt table and association with the structural inhomogeneities of the subsalt bed is presented. The authors attempt to acquire additional indirect criteria for predicting the structure of the subsalt bed by means of analyzing the structure of the salt-bearing series and the character of salt-tectogenesis manifestation. The problem solution is based on the complex analysis of the data from drilling and seismic prospecting.

Mass unbalance is a major concern in modern day rotating machinery. For single and double disc rotor bearing systems, model based techniques have been used to identify the unbalance. The aim of this research is to predict the unbalance in a similar way for a paper machine’s tube roll using its virtual model. In this case study, the rotor is a large diameter continuous tube with thin walls and without any mounted disc. To identify the unbalance magnitude and phase, modal expansion and equivalent load minimization by least squares is used. The distributed equivalent load is sorted using two different methods. The first method considers only the isolated maximum load. In the second method, the load at all the nodes are taken into account. This first method is tested on a single disc rotor bearing system from literature and the unbalance parameters were predicted with good accuracy. However, for the paper machine’s tube roll, due to its continuous structure, the equivalent load is distributed more evenly across the rotor. Therefore the second method is able to predict the unbalance parameters with better accuracy.

Grease, as used for lubrication of rolling bearings, is a two-phase organogel that slowly releases oil from its gelator matrix. Because the rate of release determines the operation time of the bearing, we study this release process by measuring the amount of extracted oil as a function of time, while we use absorbing paper to speed up the process. The oil concentration in the resulting stain is determined by measuring the attenuation of light transmitted through the paper, using a modified Lambert–Beer law. For grease, the timescale for paper imbibition is typically 2 orders of magnitude larger than for a bare drop of the same base oil. This difference results from the high affinity, i.e. wetting energy per unit volume, of the oil for the grease matrix. To quantify this affinity, we developed a Washburn-like model describing the oil flow from the porous grease into the paper pores. The stain radius versus time curves for greases at various levels of oil content collapse onto a single master curve, which allows us to extract a characteristic spreading time and the corresponding oil–matrix affinity. Lowering the oil content results in a small increase of the oil–matrix affinity yet also in a significant change in the spreading timescale. Even an affinity increase of a few per mill doubles the timescale.

The purpose of this resarch was investigated the air-oil temperature field distribution under air-oil lubrication and oil lublubrication, meanwhile also study the air-oil lubrication effect under different air velocity inlet the bearing cavities of the high-speed paper machine dryer section. Base on the CFD theory, the temperature field of CARB bearing outer ring and the velocity field of the bearing cavities were simulated by the FLUENT software.Result show that air-oil lubricatin can reach the same cooling effect is contras with oil lubrication in the same heat production by roller; the best air-velocity value of air-oil lubrication system is obtain for the change of temperature and pressure in bearing cavities. It is confirm that the air-oil lubrication is viable in the high-speed paper machine dryer section.

The Runout of a shaft is defined as the deviation of the measured surface from an ideal circle rotating around its rotational axis. The total runout can be split into two main components: the mechanical and the electrical runout. The electrical runout depends on the metallurgical state of the shaft which can only be altered to a certain degree after the forging and heat treatment processes are finished. Especially large shafts for electric motors are prone for high electrical runout, because material imperfections are moved to the center of the shaft by the forging process. As there is an unfavorable ratio between bearing diameter and the largest diameter of the shaft, these imperfections will be in the area of the new shaft surface after machining. Statistics have proven that material inhomogeneity generating an electrical runout occurs in almost all kinds of steel. This paper will provide some information about how to eliminate uncertain material properties causing the electrical runout. One measure will be presented in detail including test results.

The spherical roller bearings, used to support the drier rolls in paper machines, experience premature failure in which external heating and water contamination of the lubricant have been implicated. An apparatus was designed, built and commissioned to simulate the conditions acting on these bearings. A pilot study was performed to examine the effect of the external heating on lubricant film thickness and ultimately on bearing failure. The amount of surface damage sustained by the test bearings increased as the estimated lambda parameter decreased. Furthermore, oil deposit formation was similar to that reported in the literature for drier roll bearings, thereby supporting the validity of the experimental simulation.

This article presents a novel data-driven method of abnormal pattern identification for real-time monitoring of faults that are evolving within a rotating machine. The concept is built upon partitioning of Hilbert spectrum that are generated on intrinsic mode functions (Hilbert-Huang spectrum) of a measured vibration signal. The partitioning is further used for feature (pattern) extraction based on symbolic dynamic filtering ( SDF ). The statistical patterns are generated and used for identifying any possible damage in the rotating machinery. The proposed method is not only capable of detecting small anomalies (i.e. deviations from the nominal condition) in the vibration pattern, but also quantifies the extent of anomalies within an observed signal, thereby generating early warnings on damage initiation. The proposed realtime fault monitoring algorithm has been validated on vibration data recorded on a bearing test-bed, where system behavior gradually changes because of the accruing damage in bearing components.

Laminated object manufacturing (LOM) is one of the commercialized rapid prototyping (RP) processes, where a focused laser is usually used to cut the cross-section contours of a 3 D part and the grid hatchings of the part-exterior region on a sheet paper stack-wise. Using a laser beam as a cutter can be costly, and the thermal burning of a sheet paper along a laser scanning path can also cause an environment-polluting smoke. This paper presents a paper laminating RP system using a knife as the paper cutter instead of a laser beam. The knife holder is mounted through a radial bearing on the X-Y positioning mechanism in such a way that the knife tip is eccentric to the bearing axis by a small distance (so-called offset). Therefore, the knife tip, which engages into the sheet paper during cutting, tends to follow the path of the XY-driven bearing axis by the error that depends on the path tangential and the eccentricity of the knife tip. A tractrix model is applied to describe the kinetic motion of the knife tip and a method is formulated to compensate for the tracing error of the eccentric knife tip by modifying the original cross-section contours of the part for each layer based on the tractrix equation. A study has also been performed regarding the effect of the knife tip geometry on the cutting notch of the sheet paper and on the roughness of the finished part.

Conventional bricks are the most elementary building materials for houses construction. However, the rapid growth in today's construction industry has obliged the civil engineers in searching for a new building technique that may result in even greater economy, more efficient and durable as an alternative for the conventional brick. Moreover, the high demands for having a speedy and less labour and cost building systems is one of the factor that cause the changes of the masonry conventional systems. These changes have led to improved constructability, performance, and cost as well. Several interlocking bricks has been developed and implemented in building constructions and a number of researches had studied the manufacturing of interlocking brick and its structural behaviour as load bearing and non-load bearing element. This technical paper aims to review the development of interlocking brick and its structural behaviour. In conclusion, the concept of interlocking system has been widely used as a replacement of the conventional system where it has been utilized either as load bearing or non-load bearing masonry system.

Ceramics are used in hip implants and have been found to produce lower wear rates. This paper discusses the advantages and disadvantages of ceramics compared to other implant materials. Different types of ceramics that are being used are reviewed in terms of the wear characteristics, debris released, and their size together with other biological factors. In general, the wear rates in ceramics were lower than that of metal-on-metal and metal-on-polyethylene combinations. Results from several clinical studies are summarized in this paper providing full details from the published literature in this overview.

Many current vibration-based maintenance (VBM) policies for rolling element bearings do not use as much as possible of their useful lives. Evidence and indications to prolong the bearings' mean effective lives by using more accurate diagnosis and prognosis are confirmed when faulty bearing installation, faulty machinery design, harsh environmental condition and when a bearing is replaced as soon as its vibration level exceeds the normal. Analysis of data from roller bearings at two paper mills suggests that longer bearing lives can be safely achieved by increasing the accuracy of the vibration data. This paper relates bearing failure modes to the observed vibration spectra and their development patterns over the bearings' lives. A systematic approach, which describes the objectives and performance of studies in two Swedish paper mills, is presented. Explanations of the mechanisms behind some frequent modes of early failure and ways to avoid them are suggested. It is shown theoretically, and partly confirmed by the analysis of (unfortunately incomplete) data from two paper mills over many years, that accurate prediction of remaining bearing life requires: (a) enough vibration measurements, (b) numerate records of operating conditions, (c) better discrimination between frequencies in the spectrum and (d) correlation of (b) and (c). This is because life prediction depends on precise knowledge of primary, harmonic and side-band frequency amplitudes and their development over time. Further, the available data, which are collected from relevant plant activities, can be utilized to perform cyclic improvements in diagnosis, prognosis, experience and economy.

Imperfections in a rotor-bearing system may cause undesirable subcritical resonances occurring when the rotating speed of the rotor is a fraction of the natural frequency of the system. These resonances arise partly from rotor imperfections and partly from bearing imperfections. This study demonstrates that the subcritical twice-running-speed vibrations originating from bearing waviness may be investigated by combining a simplified rotor model with a detailed bearing model, using a finite element method. The rotor-bearing system under investigation is a roller test rig consisting of the tube roll of a paper machine supported by spherical roller bearings. The bearing waviness from the second to the fourth orders is emulated as accurately as possible in the finite element model. This is achieved by measuring the waviness of the real bearings and then incorporating the measurement results into a simulation model. The tube roll of the test rig is modeled as a symmetric tube, neglecting the effects of the uneven mass and stiffness distribution of the roll. The contact between the rotor and the bearings is described using nonlinear Hertzian contact theory. The subcritical responses of the system are studied by means of time integration, and the results are converted into the frequency domain using fast Fourier transformation. The results of the analysis are compared with the measurement results for the subcritical responses of the roll. The agreement between the simulation and experimental results of the studied system can be observed even though rotor imperfections are not considered.

Airshafts are commonly used in manufacturing processes for fitting to a reel that is used for winding rolls of material such as paper, card and plastic film. An airshaft is designed so that, on fitting into a reel, it can be readily expanded, thereby achieving a firm attachment: it may also be easily contracted prior to dismantling to facilitate removal. Their efficient design makes them ideal for quick and firm attachment onto a reel and then mounting onto bearing housings to enable the winding or unwinding of rolls of stock material with the minimum of equipment down time. The inherent shape and functionality of an airshaft means that failure by fatigue and fracture is a major concern. The airshaft, for example, has a cross-section which changes along its length and it is subjected to significant bending stresses, which alternate with rotation. The weight of the roll of material will also change appreciably during operation and, in addition, the inflated inner tube pressure further increases stress levels at critical locations. This paper analyses the service failure of a specific airshaft, from both fatigue crack initiation and crack propagation considerations, and discusses how the failure might have easily been avoided.

The number of metal-on-metal bearings used clinically continues to increase, particularly in young, active patients. The single greatest concern with the use of a metal-on-metal bearing continues to be the elevated levels of metal ions measurable in patients' blood and urine following implantation. There are multiple complex issues associated with the analysis of metal ions, including collection techniques, analysis, statistical methodologies, and reporting of results. To date, the literature on this topic has been characterized by significant variability in all of these factors. This paper seeks to establish a consensus among 3 investigators who have been working in this area and to offer guidelines on the complex methodology involved in the evaluation of metal concentration in patients following metal-on-metal hip arthroplasties.

High efficiency engines that operate at high temperatures (400-1500 °F) mandate new innovative lubrication schemes to achieve success. The most significant technical obstacle is the lubrication and wear at these high temperatures. Liquid lubricants and conventional bearing designs may not be adequate to meet existing goals. Recent understanding of the nature of third body or particulate solid dynamics suggests an alternative to conventional liquid lubrication and solid (coatings) lubrication systems. It is postulated that a layered shearing of compacted triboparticulates generates velocity, pressure, density, and temperature profiles akin to those in the liquid lubricant in a fluid film bearing. Thus triboparticulates can be either injected between the mating surfaces or generated by wear so as to generate the required flows and pressures to lubricate. This paper describes a procedure used to select suitable triboparticulates and experiments that are used to develop a fundamental understanding of their behavior. The results and importance of these experiments to attaining a constitutive equation that can be used to provide design guidelines will be discussed.

The effect of journal misalignment on the performance of a big-end connecting-rod is analysed in this paper. The misalignment considered varies in magnitude and direction during all the cycle up to contact between the shaft and the bearing. The numerical procedure incorporates misalignment velocities. The technique used for bearing characteristics evaluation (minimum film thickness, friction torque, axial flow) is an extension of the mobility method of BOOKER.

In this paper, the dynamic performance of the Ruston and Homsby VEB diesel engine connecting-rod bearing is analyzed. The effect of cavitation is considered by using a cavitation algorithm, which mimics JFO boundary conditions. The effect of mass inertia is accounted for by solving coupled nonlinear equations of motion using a fourth order Runge-Kulta method. The performance is predicted for a bearing with a circular profile and two noncircular profiles, viz, worn circular and elliptical. For the circular bearing the results are compared with various published results and the predictions for the non-circular bearings are compared to those with a circular profile.

The purpose of this paper is to reveal the relation between flexibility and clearance of oil film by a co-rotating bearing (bush is rotating together with shaft in the same direction and rotation rate), which can be used for sharing load equally in planetary transmission of vehicle. The authors have adopted a theoretical approach of infinite width bearing and explained the characteristics of oil film for co-rotating bearing. Using the numerical calculation to solve the non-linear equation, the authors have gotten the results on finite width co-rotating bearing. By experiments, the relations between flexibility and clearance of oil film for co-rotating bearing are presented by charts in different clearance, rotation rate and load. A good consistency of the results between experimental and numerical calculation result is gotten.

The purpose of this paper is to clarify a universal method to calculate the speed ratio and the power transmission efficiency of rolling contact continuously variable transmissions with planetary cones (differential type CVT). The authors present a new method in which the instantaneous center of rotation and the speed and torque efficiencies were effectively used. This method can be used to derive the equations for calculating the ratio and the efficiency of any types of CVT's and gear drives with complex mechanism. Using the equations obtained in the present investigation, numerical calculations were conducted in the case of a differential CVT with planetary cones. The calculated results agreed well with the experimental ones when the oil churning and bearing losses were taken into account.

Previous attempts to predict the film thickness in synovial joints have been hindered by inadequate modelling of the joint prior to analysis. It is well known that elastohydrodynamic action between the low elastic modulus (soft) layers of cartilage plays a major role in the effective lubrication of synovial joints, yet it is only recently that the finite thickness of the layers has been incorporated into the analysis. Furthermore, analysis of the lubrication of such layers has been restricted to nominal line contacts, whereas the hip joint presents an essentially point or circular contact problem. In this paper we present a point contact, elastohydrodynamic lubrication analysis for low elastic modulus layers of bearing material mounted on rigid substrates. The solutions indicate the magnitude of the ‘side-leakage’ correction factors which have to be introduced in any complete lubrication analysis of realistic models of synovial joints.

The generation of ultra-high molecular weight polyethylene (UHMWPE) wear particles from bearing surfaces in patients remains a major concern with long term implants. Both the volume and morphology of the wear debris are important factors in determining the response of the body to particles and subsequent effects on secure fixation. Uni-directional tri-pin on disc tests of UHMWPE sliding on a smooth stainless steel counterface have shown a low underlying wear rate with periodic transient increases in wear rate of the UHMWPE pins. Monitoring of the topography of the wear pins revealed the formation of ridges in the surface parallel to the direction of travel. The periodic increases in wear rate corresponded to the loss of UHMWPE from the tops of the ridges subjected to the largest deformations. Birefringent micrographs of sections of UHMWPE pins cut perpendicular to the surface showed residual sub-surface shear strains under these ridges. The sub-surface strains were much higher in the sections cut parallel to the direction of sliding than in those perpendicular to the sliding direction. Wear debris collected from the fluid consisted of two types, the first having a large aspect ratio and the second being more granular. Wear debris was also attached to the trailing edge of the pin in the form of an extruded ribbon of few microns thick. The observations indicated that a sub-surface failure mechanism operating on a macroscopic scale caused the incremental increases in the wear rate. The intermittent higher wear rates were associated with the removal of UHMWPE that had been subjected to the highest deformations. After the removal of the highly strained material the wear rate returned once more to the underlying lower wear rate assocaited with a particular level of counterface asperity interactions with the UHMWPE.

A mass-conserving simulation algorithm for cavitating hydrodynamic lubrication has been described elsewhere. The algorithm, which is particularly well adapted to finite element implementation, is outlined qualitatively and demonstrated quantitatively through real and ideal engine bearing applications studied previously by others. Present simulation results and previous data agree reasonably closely for these applications, providing a limited validation of the present algorithm and demonstrating the importance of mass conservation in engine bearing design analysis.

The modern concept of a car wheel bearing is a complete unit that is ready to use, greased and sealed for life. Thus today the lubricant and the seal form an integral part of the bearing. With ongoing improvement in bearing internal geometry and materials, the performance of the seal can even replace rolling contact fatigue as the limiting factor for bearing service life. At the same time, demands for reliability and long, service-free running periods are continuously increasing. Systematic efforts during recent years have resulted in improved seal designs and have provide deeper insight into their functioning and the tribology effects involved. Seals for grease lubricated bearings are defined as active hydrodynamic engineering elements, with a preferential outward pumping effect to prevent penetration of foreign matter into a bearing unit. Seal life is thus governed by the existence of preferential pumping effects. When these have vanished, the seal transforms from an active into a passive engineering element. Bearing life from then depends on environmental factors only. Several mechanisms were identified which influence these effects negatively and thus restrict seal life: of these ageing of the seal lip material and counterface abrasive wear are described. Limiting factors were found and incorporated in a seal life model.

Experimental investigations on connecting-rod bearings in operating engines required the use of a mechanical scissor linkage to support the wires carrying the electronic signals. In many applications, one end of the linkage is attached to the big-end bearing cap by a yoke, the other end being fixed to the engine frame. The mass and inertia of the linkage modify the load acting to the bearing and change the bearing characteristics. The effect of the mechanical linkage is estimated by carrying out both rigid and elastic bearing calculations with and without a contribution from the linkage to the connecting-rod load. The loads arising from the yoke and links on the connecting-rod were calculated as a function of crankangle for different crankshaft speeds. The calculations showed that the linkage and yoke increase the inertial part of the load diagramm by about 10% and modify the orbit of the bearing center at small eccentricity ratios.

Methods of calculating oil flow in connecting rod big end bearings are discussed and a numerical example typical of engine practice is presented. The commonly used oil feed arrangement for connecting rod bearings, consisting of a single hole emerging from the crank pin, results in small flows and the bearing oil film may be depleted. It is therefore necessary to consider a rigorous ‘oil film history’ model where the transportation and availability of oil in the bearing clearance is allowed for. Cycle-averaged oil flow results for over 150 bearing cases are summarized in design chart and equation form. The design charts are of two types, one relating the flow from the rigorous oil film history method with the oil flows based on rapid methods. The other type considers directly the many engine and bearing parameters involved thus making this technique suitable for general use. Also included are sensitivity charts showing the effect on oil flow of changes in particular parameters.

Empirically-derived correlations of dimensionless flow and load are presented as a direct means of predicting cycle-averaged feed pressure and hydrodynamic flows in ungrooved connectingrod bearings which are pressure-lubricated through a crankpin feed hole. The correlations allow quick estimation of flow sensitivity to small engine/bearing dimensional variations, as well as provide a simple relation that indicates when feed pressure flow can be a good indicator of actual flow.

The use of Fourier Transform Infra-Red (FT-IR) analysis for the indirect tribological control of thick manganese-iron phosphate coatings on steel substrates has been demonstrated. Using a time series of coated samples and test plain bearings prepared from an intensively used phosphating bath, a strong correlation was found between the lubricated sliding friction, the bearing endurance life and the peak shift and form of the IR spectra. The chemical structure of the phosphate layer as defined by IR analysis of the major functional groups will influence the physical properties of the layer and in turn its tribological behaviour.

Recent developments in chemical vapor deposition (CVD) technology have made it possible to produce thin diamond films on a variety of substrate materials. Diamond, having a very high hardness and low sliding friction coefficient, is a good candidate for tribological applications. Diamond films produced by a hot-filament CVD method often have irregular surfaces owing to the preferred growth mode of the crystals which form on the surface. This investigation using sapphire and bearing steel spherically tipped sliders demonstrated that the morphology of the diamond film surface produces friction coefficients up to ten times those observed in previous experiments which involved smooth diamond surfaces sliding against various solids in air.

The cushion bearing concept involved the potential application of elastomeric surface layers, with a compliance similar to cartilage, in total joint replacement implants. In the present study, experiments were performed on a cushion bearing to investigate the possibility of fluid film lubrication and to compare the measured friction coefficients with theoretical predictions. A pendulum simulator apparatus was modified extensively for the experiments. The measured friction coefficients had a rising characteristic with increasing Sommerfeld parameter which suggested fluid film lubrication and a comparison of predicted film thickness to surface roughness supported this contention. However, the measured friction coefficients did not show good qualitative agreement with theory

Soft metallic coatings play an important part in many forming processes. Two cases are investigated hereafter: * forging of anti-friction alloy coated plain bearing. Application of a mechanical model shows how it is possible to design the process so that a constant coating thickness in the final bearing wall is obtained. Computation of interfacial strain explains the improved adherence of the coating. * co-extrusion or co-drawing of coated bar or wire. A mechanical model explains coating losses during wire-drawing; in the case of brass coated steel cord, these losses lead to an evolution of surface composition.

In practical applications a rubber-like is often deposited on the internal surface of the housing to improve the bearing performance. In the present work, the influence of this layer on the bearing static and dynamic behaviour is examined by taking into account the housing deformation. A parametrical study is carried out to evalute the influence of different types of housings. It is found that the transmissibility is under-estimated in the case of rigid bearings and that a critical layer thickness exits for which the transmissibility is maximum.