scholarly journals Mathematical model of a ferromagnetic lubricant in the presence of a porous coating in the bearing structure

2021 ◽  
Vol 2061 (1) ◽  
pp. 012038
Author(s):  
A N Opatskikh ◽  
M V Novakovich
Keyword(s):  
Bearing Capacity ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Flow Equation ◽  
Porous Coating ◽  
Operating Characteristics ◽  
Support Ring ◽  
Liquid Lubricant ◽  
Incomplete Filling ◽  
The Coefficient Of Friction

Abstract Based on the flow equation of a ferromagnetic liquid lubricant for a “thin layer”, the continuity equation and Darcy’s equation describing the flow of a lubricant in a porous body, an exact self-similar solution of wedge-shaped sliding support with a porous coating of the surface of the support ring is found, taking into account the dependence of the viscosity of the ferromagnetic lubricant and the permeability of the porous coating with the incomplete filling of the working gap. Analytical dependencies for the velocity and pressure fields in the lubricating and porous layer are obtained. Also, the main operating characteristics are determined load-bearing capacity and friction force. The numerical analysis of the theoretical results showed that the bearing capacity of the bearings can be increased by 8-12% in the range of the studied load-speed modes. At the same time, the coefficient of friction is reduced by 14-16%. To verify and confirm the effectiveness of the obtained theoretical models, an experimental study of a modified wedge-shaped sliding support on TP-22C, MS-20 oil and their mixture with various additives was carried out. As a result of theoretical and experimental studies, tribotechnical characteristics were determined that allow us to judge the presence of a long-term friction mode.

scholarly journals Computational model of a micropolar lubricant with a non-standard support profile and a metal coating at incomplete filling of the working gap

2021 ◽  
Vol 2061 (1) ◽  
pp. 012037
Author(s):  
G D Vernigora ◽  
E V Kruchinina ◽  
M A Mukutadze
Keyword(s):  
Bearing Capacity ◽  
Rheological Properties ◽  
Friction Force ◽  
Friction Pair ◽  
Mechanical Energy ◽  
Metal Alloy ◽  
Metal Coating ◽  
Flow Mode ◽  
Operating Characteristics ◽  
Incomplete Filling

Abstract The authors propose an asymptotic and exact self-similar solution for zero (without considering the melt) and the first (considering the melt) approximation of a wedge-shaped sliding support with a profile adapted to friction and a fusible metal coating of the guide surface. The solution is based on the equation of a micropolar liquid flow for a “thin layer”, the continuity equation, as well as the equation describing the profile of the molten contour of a guide coated with a fusible metal alloy. The authors have taken into account the formula of the rate of mechanical energy dissipation as well as rheological properties of the lubricant and the melt, which have micropolar properties in the laminar flow mode at incomplete filling of the working gap. Analytical dependences have been obtained for the profile of the molten surface of the guide coated with a low-melting metal alloy, as well as for the velocity and pressure fields at zero and first approximation. In addition, the main operating characteristics of the friction pair under consideration have been determined: the bearing capacity and the friction force. The article contains estimation of the influence of the parameters conditioned by coating melt and adapted to the friction conditions of the support profile, and the parameter characterizing the rheological properties of the lubricant, as well as the length of the loaded area in terms of bearing capacity and friction force.

One-Dimensional Contact Pressure Distribution of Radial Tires in Motion

1995 ◽  
Vol 23 (2) ◽  
pp. 116-135 ◽  
Author(s):  
H. Shiobara ◽  
T. Akasaka ◽  
S. Kagami ◽  
S. Tsutsumi
Keyword(s):  
Pressure Distribution ◽  
Contact Pressure ◽  
Experimental Studies ◽  
Rolling Resistance ◽  
Leading Edge ◽  
Forward Direction ◽  
Contact Pressure Distribution ◽  
Support Ring ◽  
One Dimensional ◽  
Lowered Pressure

Abstract The contact pressure distribution and the rolling resistance of a running radial tire under load are fundamental properties of the tire construction, important to the steering performance of automobiles, as is well known. Many theoretical and experimental studies have been previously published on these tire properties. However, the relationships between tire performances in service and tire structural properties have not been clarified sufficiently due to analytical and experimental difficulties. In this paper, establishing a spring support ring model made of a composite belt ring and a Voigt type viscoelastic spring system of the sidewall and the tread rubber, we analyze the one-dimensional contact pressure distribution of a running tire at speeds of up to 60 km/h. The predicted distribution of the contact pressure under appropriate values of damping coefficients of rubber is shown to be in good agreement with experimental results. It is confirmed by this study that increasing velocity causes the pressure to rise at the leading edge of the contact patch, accompanied by the lowered pressure at the trailing edge, and further a slight movement of the contact area in the forward direction.

A Relativistic Newtonian Mechanics Predicts with Precision the Results of Recent Neutrino-Velocity Experiments

2014 ◽  
Vol 6 (1) ◽  
pp. 1032-1035 ◽  
Author(s):  
Ramzi Suleiman
Keyword(s):  
Null Hypothesis ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Newtonian Mechanics ◽  
Speed Of Light ◽  
Symmetry Principle ◽  
Proposed Model ◽  
Significant Difference ◽  
The One ◽  
Complete Collapse

The research on quasi-luminal neutrinos has sparked several experimental studies for testing the "speed of light limit" hypothesis. Until today, the overall evidence favors the "null" hypothesis, stating that there is no significant difference between the observed velocities of light and neutrinos. Despite numerous theoretical models proposed to explain the neutrinos behavior, no attempt has been undertaken to predict the experimentally produced results. This paper presents a simple novel extension of Newton's mechanics to the domain of relativistic velocities. For a typical neutrino-velocity experiment, the proposed model is utilized to derive a general expression for . Comparison of the model's prediction with results of six neutrino-velocity experiments, conducted by five collaborations, reveals that the model predicts all the reported results with striking accuracy. Because in the proposed model, the direction of the neutrino flight matters, the model's impressive success in accounting for all the tested data, indicates a complete collapse of the Lorentz symmetry principle in situation involving quasi-luminal particles, moving in two opposite directions. This conclusion is support by previous findings, showing that an identical Sagnac effect to the one documented for radial motion, occurs also in linear motion.

scholarly journals Experimental Evaluation of Airlift Performance for Vertical Pumping of Water in Underground Mines

2021 ◽  
Author(s):  
Parviz Enany ◽  
Oleksandr Shevchenko ◽  
Carsten Drebenstedt
Keyword(s):  
Water Flow ◽  
High Efficiency ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Injection System ◽  
Experimental Investigations ◽  
Flow Mode ◽  
New Device ◽  
Riser Pipe ◽  
Airlift Pump

AbstractThis paper presents experimental studies on the optimization of air–water flow in an airlift pump. Airlift pumps use compressed gas to verticall transport liquids and slurries. Due to the lack of theoretical equations for designing and predicting flow regimes, experimental investigations must be carried out to find the best condition to operate an airlift pump at high efficiency. We used a new air injection system and different submergence ratios to evaluate the output of a simple pump for vertical displacement of water in an underground mine. The tests were carried out in a new device with 5.64 m height and 10.2 cm circular riser pipe. Three air-jacket pipes, at different gas flows in the range of 0.002–0.09 m3/s were investigated with eight submergence ratios. It was found that with the same air flow rate, the most efficient flow of water was achieved when an air jacket with 3 mm diameter holes was used with a submergence ratio between 0.6 and 0.75. In addition, a comparison of practical results with two theoretical models proposed by other investigators showed that neither was able to accurately predict airlift performance in air–water flow mode.

Experimental Studies on Axially Loaded Concrete Columns Confined by Different Materials

2008 ◽  
Vol 400-402 ◽  
pp. 513-518 ◽  
Author(s):  
Yong Chang Guo ◽  
Pei Yan Huang ◽  
Yang Yang ◽  
Li Juan Li
Keyword(s):  
Bearing Capacity ◽  
Glass Fiber ◽  
Failure Modes ◽  
Experimental Studies ◽  
Concrete Columns ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Advantages And Disadvantages ◽  
Axially Loaded ◽  
Normal Strength

The improvement of the load carrying capacity of concrete columns under a triaxial compressive stress results from the strain restriction. Under a triaxial stress state, the capacity of the deformation of concrete is greatly decreased with the increase of the side compression. Therefore, confining the deformation in the lateral orientation is an effective way to improve the strength and ductility of concrete columns. This paper carried out an experimental investigation on axially loaded normal strength concrete columns confined by 10 different types of materials, including steel tube, glass fiber confined steel tube (GFRP), PVC tube, carbon fiber confined PVC tube (CFRP), glass fiber confined PVC tube (GFRP), CFRP, GFRP, polyethylene (PE), PE hybrid CFRP and PE hybrid GFRP. The deformation, macroscopical deformation characters, failure mechanism and failure modes are studied in this paper. The ultimate bearing capacity of these 10 types of confined concrete columns and the influences of the confining materials on the ultimate bearing capacity are obtained. The advantages and disadvantages of these 10 types of confining methods are compared.

scholarly journals Physico-technical approach to design of composites from mineral and polymer technogenic resources

2015 ◽  
Vol 1 ◽  
pp. 162 ◽  
Author(s):  
Gotfrīds Noviks
Keyword(s):  
Composite Materials ◽  
Experimental Studies ◽  
Process Efficiency ◽  
Operating Characteristics ◽  
Forming Process ◽  
Polymer Waste ◽  
Composite Forming ◽  
Different Types ◽  
Low Levels

<p class="R-AbstractKeywords"><span lang="EN-US">Artificial composite materials are currently being produced in large quantities, they are diverse and they are widely used in the economy. There have been extensive theoretical and experimental studies of different types of components, developed the calculation methods of composites production with predefined properties.</span></p><p class="R-AbstractKeywords"><span lang="EN-US">At the same time industry produces a lot of mineral and polymer waste, which are practically technogenic resources, but their use is currently at quite low levels. The paper examines the possibilities to use technogenic resources- mineral (such as ash and clay) and organic (polymers -PET containers) for producing qualitative composite materials. For this purpose theoretical analysis and calculations of the physical properties of components and process parameters that determine the operating characteristics of the composite material were carried out.</span></p><p class="R-AbstractKeywords"><span lang="EN-US">Composite-forming process efficiency determinative parameters were analysed: adhesion, the specific surface energy, specific free surface, adsorption capacity and the degree of dispersion of the particles.</span></p><p class="R-AbstractKeywords"><span lang="EN-US">The role of external factors in processing of composite were examined – temperature, concentration of components.</span></p><p class="R-AbstractKeywords"><span lang="EN-US">The characteristics of prepared samples of composites showed the possibility to use these waste for the development of qualitative products for different purposes.</span></p>

scholarly journals DETERMINATION OF DEFORMATION IN MESH COMPOSITE STRUCTURE UNDER THE ACTION OF COMPRESSIVE LOADS

2020 ◽  
Vol 17 (35) ◽  
pp. 599-608 ◽  
Author(s):  
Alexander A. OREKHOV ◽  
Yuri A. UTKIN ◽  
Polina F. PRONINA
Keyword(s):  
Composite Material ◽  
Carbon Fiber ◽  
Bearing Capacity ◽  
Polymer Composite ◽  
Experimental Studies ◽  
Polymer Composite Material ◽  
Lightweight Mesh ◽  
Carbon Filler ◽  
Selection Of

One of the significant innovative technologies is the creation of large-sized structures that work for a long time in space and meet stringent restrictions on overall mass characteristics. Among these structures, in the first place, is the section of bearing truss (BT). This article presents the results of experimental studies of sectors of load-bearing trusses of mesh design for compression. Recently, composite mesh cylindrical shells are used as spacecraft housings. The mesh shell is a supporting structure to which the instruments and mechanisms of the spacecraft are attached. The truss section is made of cross-linked polymer composite material with carbon fibers. The objective of the tests is to confirm the possibility of creating a lightweight mesh construction using a carbon fiber reinforced polymer composite material. To achieve this goal, the authors were assigned the following tasks: selection of carbon filler of polymer composite materials (PCM); selection of PCM binder; determination of the degree of carbon fiber reinforcement; choice of the number and orientation paths of spiral ribs, number of ring ribs and the sizes of individual ribs. As a result of the research, the calculated indicators for ensuring the bearing capacity and stiffness under the application of axial compressive load were obtained. At the same time, with the determination of bearing capacity, the deformation characteristics of the structure were twice determined in order to confirm their repeatability, as well as linear nature of the dependence of axial and radial deformations as a result of the applied load.

Theoretical and experimental investigation of non-asbestos friction lining material applied in automotive drum brake

2019 ◽  
Vol 234 (6) ◽  
pp. 972-985
Author(s):  
Dinesh Subhash Shinde ◽  
KN Mistry ◽  
Mukesh Bulsara
Keyword(s):  
Coefficient Of Friction ◽  
Test Procedure ◽  
Frictional Resistance ◽  
Theoretical Models ◽  
Surface Phenomenon ◽  
Vehicle Speed ◽  
Lining Material ◽  
The Coefficient Of Friction ◽  
Brake Lining ◽  
Friction Lining

Automotive brakes are the important machine element which provides an artificial frictional resistance to control the speed of an automobile. In the present work, theoretical models for the coefficient of friction between brake drum and friction liner are generated and simulated using MATLAB Simulink. A test set up designed and manufactured according to the brake lining quality test procedure (SAE J661) is used to investigate tribological properties of a non-asbestos friction lining material having 11 different constituents, which is manufactured from one of the brake liner manufacturer. An experiment is designed using response surface methodology (RSM) with vehicle speed, braking force, and sliding distance as the input parameters, whereas coefficient of friction and wear as an output. It is found that vehicle speed is the most significant parameter among the three. Fade and recovery behavior of the friction lining material is also studied and it is found that the developed friction lining material satisfies the criteria specified in SAE J661. Scanning electron microscope (SEM) and energy dispersive spectoscopy (EDS) have revealed the significant surface phenomenon.

A Review of Theoretical and Experimental Research on Various Autofrettage Processes

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Rajkumar Shufen ◽  
Uday S. Dixit
Keyword(s):  
Experimental Studies ◽  
Theoretical Models ◽  
Pressure Vessels ◽  
Future Research ◽  
Spherical Vessel ◽  
Considerable Research ◽  
Wide Range ◽  
Set Up ◽  
Compressive Residual Stresses ◽  
Spherical Pressure

Autofrettage is a metal forming technique widely incorporated for strengthening the thick-walled cylindrical and spherical pressure vessels. The technique is based on the principle of initially subjecting the cylindrical or spherical vessel to partial plastic deformation and then unloading it; as a result of which compressive residual stresses are set up. On the basis of the type of the forming load, autofrettage can be classified into hydraulic, swage, explosive, thermal, and rotational. Considerable research studies have been carried out on autofrettage with a variety of theoretical models and experimental methods. This paper presents an extensive review of various types of autofrettage processes. A wide range of theoretical models and experimental studies are described. Optimization of an autofrettage process is also discussed. Based on the review, some challenging issues and key areas for future research are identified.

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