scholarly journals INCREASE OF OPERATING RELIABILITY OF THE TRAVEL WHEEL USING THE USE OF THE ELASTIC INSERTS

2020 ◽  
Vol 5 ◽  
pp. 69-76
Author(s):  
Nataliia Fidrovska ◽  
Evgen Slepuzhnikov ◽  
Oleksiy Larin ◽  
Ivan Varchenko ◽  
Voloymyr Lipovyi ◽  
...  
Keyword(s):  
Rational Design ◽  
Theoretical Data ◽  
Operating Mode ◽  
Operational Reliability ◽  
Overhead Crane ◽  
Dynamic Factors ◽  
Repair Costs ◽  
Urgent Task ◽  
Dynamic Forces ◽  
Crane Wheel

The aim of research is to substantiate the rational design of the travel wheel based on the determination of the dynamic forces arising from the movement of the freight carriage and the crane bridge. The research methodology is based on analytical methods for studying dynamic forces in the mechanism of movement of the cargo carriage of an overhead crane. The obtained solution of the three-mass dynamic scheme of the movement of the freight carriage. To verify the theoretical data obtained, an experiment was carried out on an overhead crane with a lifting capacity of 5 , span of 22.5 m, lifting height of 8 m, operating mode of 7 K. The study of the vibration state was carried out on the crane beam in the middle of the span, on the axis of the driven wheel of the crane trolley with an elastic insert and on the axis of the drive wheel of the crane trolley of a conventional design. Crane wheels are the fastest wearing parts of a crane. A decrease in their durability leads to an increase in repair costs and crane downtime. Therefore, increasing the durability of crane travel wheels is an urgent task of modern crane construction. All designs of travel wheels are quite rigid and do not perceive shocks and distortions arising from the deviation of the rail track from the recommended values and lead to significant wear of the flanges and rails. The analysis of the obtained solutions showed that when using a travel wheel with an elastic insert, the dynamic factors during the movement of the freight carriage decrease. Dependences are obtained for determining the dynamic forces arising from the movement of the travel crane wheel, taking into account the rigidity of the elastic ring, which is installed in the travel wheel. The analysis of the regularities of the formation of vibration signs at different points of the overhead crane structure is carried out. The proposed design and calculation method for a travel wheel with an elastic insert improves its operational reliability

scholarly journals JUSTIFICATION OF THE STRUCTURE OF THE CRANE WHEEL WITH ELASTIC INSERT

2021 ◽  
pp. 35-43
Author(s):  
Nataliia Fidrovska ◽  
Evgen Slepuzhnikov ◽  
Roman Ponomarenko ◽  
Dmytro Kozodoi
Keyword(s):  
High Speed ◽  
Rational Design ◽  
Operational Reliability ◽  
Running Wheel ◽  
Dynamic Factors ◽  
Transmission Shaft ◽  
Medium Speed ◽  
Dynamic Forces ◽  
Crane Wheel ◽  
Running Wheels

The article considers the modernized design of the crane running wheel with anelastic insert.The purpose of the study is to substantiate the rational design of the running wheel onthe basis of determining the dynamic forces that occur when moving the truck and the crane bridge.Crane equipment is of great importance for the mechanization of lifting and transportoperations in various industries. Bridge cranes perform various lifting and transport operations.Installation and dismantling of equipment and machines. Also take part in the technologicalprocess of the metallurgical industry.The costs associated with the replacement and restoration of the running wheels are 15-17%of the cost of repairing the entire crane. At the same time more than 90% of crane wheels fail due towear of flanges.The main tasks for the diagnosis of crane wheels and rail tracks are usually solved duringscheduled maintenance by visual inspection of the wheel and rail and identify their wear. But thisdiagnostic tool does not quite satisfy the modern conditions of the cranes, namely, the compatiblecondition of the wheels and rails is not assessed, and it is impossible to carry out such controlconstantly during operation.Mechanisms for moving bridge cranes have several designs. The mechanism for moving thetruck, as a rule, has one drive, which transmits motion to the two drive wheels. The mechanisms ofmovement of the crane can be with the central and separate drive. The mechanisms of movement with the central drive can be with a low-speed transmission shaft, with a high-speed transmissionshaft and with a medium-speed transmission shaft.With this design, the gearbox shafts are connected to the drive wheel shaft by means of aclutch and a transmission shaft. This impairs the operation of the entire mechanism, because thepresence of the transmission shaft increases the complexity of the manufacture of the crane and itsweight and requires a very precise installation.To overcome these shortcomings, a separate drive of the end beams of the bridge is used.If the load on one of the support beams of the bridge is less than on the other, the enginespeed on this support increases and the support begins to run forward relative to the more loadedsupport. But the first engine begins to receive increased load, which is transmitted through themetal structure of the bridge and unloads the engine of the second support, due to which the speedof the first engine decreases and the speed of the second engine increases until they are equalized.Thus, in the process of moving the crane with a separate drive is the redistribution of loadbetween the two engines. Although the scheme of the mechanism with separate drives requires twoengines, two brakes and two gearboxes, it is the cheapest, light weight and easy to manufacture.The design of running wheels of cranes and crane carts should exclude a possibility ofderailment of wheels. To do this, the running wheels have two side flanges - flanges, which serve toguide the running wheels on the rails.The dynamic forces that arise when moving the trucks of cranes are quite large and cannot beignored when designing cranes. Most of all, they are manifested by wear of wheels and rails duringthe occurrence of distortions on the cranes.Thus, improving the performance and operational reliability of crane running wheels is avery important task of modern crane construction.The research technique is based on analytical methods of research of dynamic efforts in themechanism of movement of the truck of the bridge crane. The decision of three mass dynamicschemes of movement of the cargo cart is received.The analysis of the received decisions showed that at application of a running wheel with anelastic insert, dynamic factors at movement of the truck decreases. Dependences for determinationof dynamic forces which arise at movement of a running crane wheel taking into account rigidity ofan elastic ring which is inserted into a running wheel are received. The design and a technique ofcalculation of a running crane wheel with the vulcanized ring are offered.

Cu-doped Co3O4 nanostructures as an efficient non-noble metal electrocatalyst for methanol oxidation in basic solution

2021 ◽  
Author(s):  
Shuang Zhao ◽  
Hui Yang ◽  
Yaru Liu ◽  
Yaodong Xing ◽  
Guangwen Cui ◽  
...  
Keyword(s):  
Methanol Oxidation ◽  
Noble Metal ◽  
Oxidation Reaction ◽  
Rational Design ◽  
Methanol Oxidation Reaction ◽  
Basic Solution ◽  
Urgent Task ◽  
The Cost ◽  
Co3o4 Nanostructures

Rational design of non-noble metal electrocatalysts is an urgent task to lower the cost of electrocatalysts for methanol oxidation reaction (MOR). Herein, mesoporous Cu-Co3O4 electrocatalysts have been prepared by using...

scholarly journals INVESTIGATION OF THE DYNAMICS OF AN OVERHEAD CRANE LIFTING PROCESS IN A VERTICAL PLANE

Transport ◽  
2005 ◽  
Vol 20 (5) ◽  
pp. 176-180 ◽  
Author(s):  
Marijonas Bogdevičius ◽  
Aleksandr Vika
Keyword(s):  
Dynamic Behaviour ◽  
Equations Of Motion ◽  
Asynchronous Motor ◽  
Linear Equations ◽  
Vertical Plane ◽  
Overhead Crane ◽  
Dynamic Forces ◽  
Planet Gear ◽  
Linear Equations Of Motion ◽  
Non Linear Equations

The paper analyses the dynamic behaviour of supporting structure of an overhead crane during the operation of a hoisting mechanism. The crane is expected to operate with a hook and to carry 50 kN of weight. The electric hoist consists of an asynchronous motor with a magnetic brake, a two‐level planet gear, a load drum and an upper block. Non‐linear equations of motion of a crane hoisting mechanism are derived. Real dynamic forces and their influence on the hoisting crane behaviour are obtained. Numerical results of the crane are derived considering two hoisting regimes during the operation of the hoisting.

Do Arm Postures Vary With the Speed of Reaching?

1999 ◽  
Vol 81 (5) ◽  
pp. 2582-2586 ◽  
Author(s):  
Kiisa C. Nishikawa ◽  
Sara T. Murray ◽  
Martha Flanders
Keyword(s):  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Optimal Solution ◽  
Reaching Movements ◽  
Total Force ◽  
Joint Torques ◽  
Dynamic Factors ◽  
Human Arm ◽  
Wide Range ◽  
Dynamic Forces

Do arm postures vary with the speed of reaching? For reaching movements in one plane, the hand has been observed to follow a similar path regardless of speed. Recent work on the control of more complex reaching movements raises the question of whether a similar “speed invariance” also holds for the additional degrees of freedom. Therefore we examined human arm movements involving initial and final hand locations distributed throughout the three-dimensional (3D) workspace of the arm. Despite this added complexity, arm kinematics (summarized by the spatial orientation of the “plane of the arm” and the 3D curvature of the hand path) changed very little for movements performed over a wide range of speeds. If the total force (dynamic + quasistatic) had been optimized by the control system (e.g., as in a minimization of the change in joint torques or the change in muscular forces), the optimal solution would change with speed; slow movements would reflect the minimal antigravity torques, whereas fast movements would be more strongly influenced by dynamic factors. The speed-invariant postures observed in this study are instead consistent with a hypothesized optimization of only the dynamic forces.

Cervical Spondylotic Myelopathy: Treatment with Posterior Decompression and Luque Rectangle Bone Fusion

Neurosurgery ◽  
1991 ◽  
Vol 28 (5) ◽  
pp. 680-684 ◽  
Author(s):  
Paul Kurt Maurer ◽  
Richard G. Ellenbogen ◽  
James Ecklund ◽  
Gary R. Simonds ◽  
Bruce van Dam ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Canal ◽  
Cervical Spondylotic Myelopathy ◽  
Substantial Evidence ◽  
Posterior Decompression ◽  
Neurological Improvement ◽  
Bone Fusion ◽  
Dynamic Factors ◽  
Dynamic Forces ◽  
Repetitive Trauma

Abstract Cervical spondylotic myelopathy appears to result from a combination of factors. The two major components are 1) compressive forces resulting from narrowing of the spinal canal, and 2) dynamic forces owing to mobility of the cervical spine. There is substantial evidence to suggest that the repetitive trauma to the spinal cord that is sustained with movement in a spondylotic canal may be a major cause of progressive myelopathy. Utilization of extensive anterior procedures that remove the diseased ventral features as well as eliminate the dynamic forces owing to the accompanying fusion have grown in popularity. Cervical laminectomy enlarges the spinal canal, but does not reduce the dynamic forces affecting the spinal cord, and may actually increase cervical mobility, leading to a perpetuation of the myelopathy. The authors propose the combination of posterior decompression and Luque rectangle bone fusion to deal with both the compressive and the dynamic factors that lead to cervical spondylotic myelopathy. Ten patients who had advanced myelopathy underwent the combined procedures. Nine of the 10 experienced significant neurological improvement, and the 10th has had no progression. The combination of posterior decompression and Luque rectangle bone fusion may offer a simple, safe, and effective alternative treatment for cervical spondylotic myelopathy.

Finite Element Analysis of Top Flanged Joint System of High Power Level Wind Turbine

2012 ◽  
Vol 591-593 ◽  
pp. 728-732
Author(s):  
Rong Zhang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Wind Turbine ◽  
Rational Design ◽  
Large Scale ◽  
Power Level ◽  
Operating Mode ◽  
Element Model ◽  
Element Analysis ◽  
Joint System

This paper uses non-linear finite element method to structurally analyze top flanged joint system of a MW wind turbine, sets up a finite element model of top flanged joint system by applying finite element analysis software MSC.Marc/Mentat, makes an analysis on the stress distribution of key components of top flanged joint system under ultimate operating mode based on applying appropriate boundary condition and loads, and carries out security examination on top flange and joint bolt. Result shows that key components of the top flanged joint system can satisfy design requirements, and it has a guiding role for rational design and performance improvement of large scale wind turbine flange, which can be used in structural analysis of other flanged joint systems, and has certain practical value in the aspect of engineering.

scholarly journals Study of Reliability for Main Components and Devices of Die-Cutting Presses for Packaging

2020 ◽  
Vol 19 (4) ◽  
pp. 320-328
Author(s):  
N. S. Kohnenko ◽  
I. I. Karpunin ◽  
V. V. Kuz'mich
Keyword(s):  
Failure Probability ◽  
High Performance ◽  
Residual Life ◽  
Operational Reliability ◽  
Operating Conditions ◽  
Single Type ◽  
Successful Operation ◽  
Urgent Task ◽  
Probabilistic Values ◽  
Main Components

A large variety of machine operating conditions leads to a difference in the wear rate even for their units being of the same type. Operational time terms of single-type units and machines are not the same, and therefore, numerical expressions of operational reliability will be probabilistic values. Incomplete restoration of original properties of a unit, a negligent repair, a poor maintenance usually lead to the fact that any of several parts independently one from another can determine reliability  of  a  machine  (a unit).  This is especially important  to  consider  when  manufacturing packaging in order to avoid rejects. The operational reliability of modern machines consisting of hundreds, and sometimes thousands of parts, wear processes of which are in a complex relationship,  depends on a number of factors. A study on reliability of main components and equipment devices is an urgent task. Successful operation of printing equipment is possible only if there is a clear organization of preventive work, ensuring preparation of printing machines for printing and post-printing processing. High-performance equipment, such as die-cutting presses, should be regularly inspected, adjusted and maintained in such a way as to obtain standard results at the output. The paper has studied reliability of main components and devices of die-cutting presses based on calculation of failure probability. Calculations have been carried out by analogy with the calculation of the probability of events in the fault tree. Failure diagrams of devices and units of die-cutting presses have been built in the paper. Based on the analysis of the failure probability for main components and devices, graphs of residual life for equipment operation on its life cycle have been constructed in the paper.

scholarly journals Dead time influence on operating modes of transistor resonant inverter with pulse frequency modulation (PFM)

2019 ◽  
Vol 10 (4) ◽  
pp. 1815
Author(s):  
Mihail Hristov Antchev ◽  
Hristo Mihailov Antchev
Keyword(s):  
Dead Time ◽  
Theoretical Data ◽  
Operating Mode ◽  
Pulse Frequency ◽  
Switching Frequency ◽  
Pulse Frequency Modulation ◽  
Zero Voltage Switching ◽  
Operating Modes ◽  
Resonant Inverter ◽  
The Impact

<p>This study explores the impact of dead-time on the transistor resonant inverter operating modes depending on the ratio of the transistor switching frequency and the resonant frequency of the series-resonance circuit in the diagonal of the transistor bridge. On the basis of theoretical data and experimental results, a dead-time limitation relation has been offered - besides for a minimum value but for a maximum value. This provides extension of the operating mode range in zero voltage switching (ZVS).</p>

scholarly journals RESEARCH OF TECHNICAL CHARACTERISTICS OF NEW TYPES OF COUPLINGS

2020 ◽  
pp. 113-121
Author(s):  
Oleksii Tokarchuk ◽  
Yurii Polievoda
Keyword(s):  
Elastic Element ◽  
Rational Design ◽  
Experimental Studies ◽  
Bending Moment ◽  
Operational Reliability ◽  
Modern Technology ◽  
Operating Conditions ◽  
The Moment ◽  
Working Bodies ◽  
Moment Of Resistance

Dynamic loads that occur during the operation of existing couplings cause significant shock loads, which leads to rapid wear of the surfaces of the couplings and shortens the service life. Modern technology faces the task of improving the operational reliability of the working bodies and drives of machines. One way to solve this problem is to develop and use high-precision and low-dynamic safety couplings. In this regard, the question of developing new designs of safety couplings that reduce impact loads and increase the reliability and durability of machinery is relevant. The synthesis of structural and kinematic schemes of ball, cam and planetary safety couplings, the method of their calculation in combination with the nature of the change in the moment of resistance on the working body of the equipment. The article conducts a set of theoretical and experimental studies to determine their rational design, kinematic and dynamic parameters that will satisfy the operating conditions of machines and mechanisms. A force analysis of the elastic element (ring spring) was performed. The scheme of loading of an elastic element by two forces and other settlement schemes are constructed, namely: equivalent system; force diagrams for determining the load torque; force schemes for determining the unit moment; schemes of total bending moment; force schemes to determine the total unit moment. During static experimental studies of the developed ball safety couplings, the nature of their operation was established, the maximum torque at the two stages of operation of the couplings was determined and a comparative analysis between the results of theoretical and experimental studies was performed. The positive results of experimental researches of the developed coupling and theoretical positions which can be applied to a substantiation and a choice of rational parameters of the developed designs of couplings and their engineering designing were confirmed.

scholarly journals COMPOSITE MATERIALS BASED ON CEMENT BINDERS MODIFIED WITH SiO2 NANOADDITIVES

2017 ◽  
Vol 16 (6) ◽  
pp. 459-465
Author(s):  
B. M. Khroustalev ◽  
S. N. Leonovich ◽  
V. V. Potapov ◽  
E. N. Grushevskaya
Keyword(s):  
Corrosion Resistance ◽  
Materials Science ◽  
Ionic Composition ◽  
Construction Materials ◽  
Operational Reliability ◽  
Strength Development ◽  
Ultrasonic Processing ◽  
Structure And Properties ◽  
Urgent Task ◽  
High Level

Development of nanotechnologies allows to solve a number of problems of construction materials science: increase in strength, durability, abrasion and corrosion resistance that determines operational reliability of building constructions. Generally it is achieved due to nanoparticles that modify the structure and properties of the existing materials or products and are entered into their volume or on a surface layer. It’s theoretically and experimentally proved that the modified water has the bigger activity owing to the change of the ionic composition influencing the рН size and other parameters. As nanoparticles have a high level of surface energy, they show the increased tendency to agglomeration, meanwhile the size of agglomerates can reach several micrometers. In this regard an urgent task is to equally distribute and disaggregate the nanoparticles in the volume of tempering water. The experiments on studying of influence of the nanoparticles of silica distributed in volume of liquid by means of ultrasonic processing on characteristics of cement and sand solution and heavy concrete have been conducted. Nanoadditive influence on density, speed of strength development, final strength under compression of materials on the basis of cement depending on nanoadditive mass percent has been established.

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