scholarly journals Diagnostics of the Excessive Wear of the Machine on a Model of Developmental, Progressive Interactions Between Diagnostic Signals and Rotation Speed Signals

2021 ◽  
Vol 51 (4) ◽  
pp. 107-141
Author(s):  
Paweł Lindstedt ◽  
Edward Rokicki ◽  
Maciej Deliś ◽  
Kamila Dobosz ◽  
Andrzej Czarnecki
Keyword(s):  
Wear Rate ◽  
Rotation Speed ◽  
Current Intensity ◽  
Static Characteristics ◽  
Inference Process ◽  
Operating Process

Abstract In the machine operating process, there are certain interactions between its operational use and wear. The current wear is increased by the current intensity of operational use, and usable potential is reduced by the current wear rate. In the diagnostic inference process, static characteristics and trajectories of state from the experiment are compared with different matrices determined for various assumed configurations of changes. As a result, the approximated diagnosis is created. This method is not universal. It applies only to the continuous progressive state, more or less increased wear rate of the machine.

Experimental study on the effect of load and rotation speed on dry sliding of silicon nitride

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Zhishuang Wang ◽  
Songhua Li ◽  
Jian Sun ◽  
Junhai Wang ◽  
Yonghua Wang ◽  
...  
Keyword(s):  
Experimental Study ◽  
Silicon Nitride ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Wear Mechanism ◽  
Rotation Speed ◽  
Friction Pair ◽  
Test Method ◽  
Dry Sliding ◽  
Content Type

Purpose The purpose of this study is to investigate the effects of load and rotation speed on dry sliding of silicon nitride, including a series of tribological behaviors (friction coefficient, wear rate, temperature rise, etc.) and wear mechanism. Through the analysis of the above characteristics, the influence law of load and speed on them and the internal relationship between them are determined, and then the best comprehensive performance parameters of silicon nitride full-ceramic spherical plain bearings in dry sliding are predicted, which can provide guidance for the operation condition of silicon nitride full-ceramic spherical plain bearings in dry sliding. Design/methodology/approach The experimental study of different loads and rotation speeds under dry friction conditions was carried out by the using ball-disk sliding test method. Findings With the increase of load, the friction coefficient of silicon nitride friction pair and the wear rate of silicon nitride ball decrease continuously. With the increase of rotation speed, the friction coefficient of silicon nitride friction pair first increases and then decreases, and the wear of silicon nitride ball first increases and then decreases. With the increase of load and rotation speed, the wear mechanism eventually changes to adhesive wear. Originality/value Because of the low timeliness and inefficiency of bearing experiments, this work adopts a simple ball-disk model to comprehensively explore the influence rules of different conditions, which provides a theoretical basis for the subsequent practical application of silicon nitride full-ceramic spherical plain bearings.

Wear Behaviors of TiCN Cermet under Different Concentrations of Abrasive Slurries from Carborundum, Corundum and Silica Sands

2010 ◽  
Vol 177 ◽  
pp. 121-124 ◽  
Author(s):  
Xiao Yong Ren ◽  
Zhi Jian Peng ◽  
Zhi Yuan Wang ◽  
Hui Yong Rong ◽  
Zhi Qiang Fu ◽  
...  
Keyword(s):  
Particle Size ◽  
Wear Rate ◽  
Rotation Speed ◽  
Test System ◽  
System Model ◽  
Wear Loss ◽  
Binder Removal ◽  
Water Based ◽  
Sliding Distance ◽  
Extensive Plastic Deformation

Through a modified ASTM B611 wet sand rubber rimmed wheel test system (model: MLS-225), the wear resistance of commercially bought TiCN cermets FD22 was studied with water-based slurries of abrasive sands. The applied abrasives were angular sands of carborundum, corundum, and silica with particle size of about 350 μm. During experiments, the rotation speed of the rubber wheel was fixed at 498 rpm, and the load was 225 N. The results show that with increasing concentration of abrasive sands in the slurry, the wear loss of the cermet samples increased. Under the same conditions, when carborundum was used as abrasive, the cermet samples presented the heaviest wear loss and the highest wear rate, but when silica was used as abrasive, the cermet samples presented the slightest wear loss and the lowest wear rate. Under the abrasive concentrations of 5-20 wt% in slurry, the wear rate remained almost unchanged as the sliding distance increased. However, when the concentration was higher than 20 wt%, as the sliding distance increased, the wear rate increased at first and gradually decreased with the sliding distance over 30 km. Through the observations of 3D white-light interfering surface profiler, it was found that the wear mechanisms of TiCN cermet samples involved in extensive plastic deformation, grooves, binder removal and fracture.

scholarly journals Investigation of the Effect of Rotation Speed on Vibration Responses of Transmission System

2019 ◽  
Vol 256 ◽  
pp. 02019 ◽  
Author(s):  
Xiaogang Liu ◽  
Zhaoyu Wu ◽  
Jie Lu ◽  
Jinli Xu
Keyword(s):  
Torsional Vibration ◽  
Rotation Speed ◽  
Excitation Frequency ◽  
Transmission System ◽  
Element Analysis ◽  
Shaft System ◽  
Maximum Value ◽  
Operating Process ◽  
Vibration Model ◽  
Vibration Responses

In the operating process, it is found the vibration of main reducer reaches a maximum value when certain types of vehicles are running at a speed around 4000 RPM. However, how the rotation speed of engine affects the vibration responses to automobile transmission system has not been investigated theoretically in details. To investigate this problem, the transmission system of automobile is simplified to a drive-final shaft system in this research, and a coupled vibration model of drive-final shaft system is developed. This model is used to simulate the vibration response to transmission system at different rotation speeds. Simulation results show that the torsional vibration responses reach the maximum when the rotation speeds are 3800 RPM and 4200 RPM and the vibration responses of pinion reach the maximum value when the rotation speeds are 4000 RPM and 4200 RPM. Moreover, finite element analysis is conducted to investigate the reason for this phenomenon. It is found that the torsional vibration responses reach the maximum value when the excitation frequency of engine is close to the resonance frequency of drive shafts. This research provides an effective method to analyse the vibration characteristics of automobile transmission system.

A New Structural Stiffness Model for Bump-Type Foil Bearings: Application to Generation II Gas Lubricated Foil Thrust Bearing

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Abdelrasoul M. Gad ◽  
Shigehiko Kaneko
Keyword(s):  
Thrust Bearing ◽  
Rotation Speed ◽  
Analytical Models ◽  
Structural Stiffness ◽  
Static Characteristics ◽  
Thrust Bearings ◽  
Foil Bearings ◽  
Compliant Structure ◽  
Stiffness Model ◽  
Foil Thrust Bearing

A new structural stiffness model for the compliant structure in foil gas bearings is introduced in the first part of this work. The model investigates the possibility that the flat segment between bumps, in bump foil strip, may deflect laterally and separate from the rigid bearing surface, and it also considers the interaction between bumps in the bump foil strip, the friction between the bump foil, and the surrounding structure. The validity of the analytical solution was verified through direct comparison with previous numerical and analytical models. In the second part of this work, the introduced bump foil model is used to investigate the static characteristics of generation II gas foil thrust bearing. The numerical simulations of the coupled fluid-structure interactions revealed that the foil thrust bearings share many features with their rigid bearing counterpart and the results showed clearly that the load carrying capacity of foil thrust bearings increases nonlinearly with the rotation speed and is expected to reach an asymptote as the rotation speed exceeds a certain value. The effects of ramp height and interface friction (i.e., friction at bump foil/rigid bearing interface and bump foil/top foil interface) on the static characteristics of generation II foil thrust bearings are investigated.

TECHNOLOGY AND EQUIPMENT FOR PROCESSING OF LARGE-SIZED VERMICULITE MICAS OF THE KOVDOR DEPOSIT

2020 ◽  
Vol 17 (2) ◽  
pp. 100-109
Author(s):  
A.I. Nizhegorodov ◽  
Keyword(s):  
Large Scale ◽  
Rotation Speed ◽  
Raw Materials ◽  
Technological Equipment ◽  
Firing Time ◽  
Processing Industry ◽  
Operating Process ◽  
Large Particles ◽  
Kovdor Deposit

The development of technology and equipment for the processing of large-sized vermiculite mica obtained from mining waste from the Kovdorsky deposit allows the large-scale vermiculite to be returned to processing industry. This article reviews the aspects of the technology for processing of large-sized mica with dimensions of 20 mm or more. The aim of the research is to study the grinding technology of large-sized vermiculite raw materials by the chopping overall particles, to develop the technological equipment and to study of its operating processes. The object of the research is the operating process of the chopping unit for grinding the large-sized vermiculite raw materials and its design. The methods are based on study of simulated movement of chopped large-sized particles and the determination of the main characteristics of the chipping unit operating process. It was found that the firing of large particles without grinding in chopping units requires a significant increase in firing time, which reduces the productivity of electric furnaces. The time of dropping particles out in the slot of the receiving drums of the chopping unit is determined, based on which the rotation speed of the receiving drums and its operational efficiency are calculated.

Cerebellopontine Angle Surgery Assisted by Continuous Mapping of the Facial Nerve Via the Ultrasonic Aspirator

2020 ◽  
Author(s):  
Marco Cenzato ◽  
Roberto Stefini ◽  
Francesco Zenga ◽  
Maurizio Piparo ◽  
Alberto Debernardi ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Facial Nerve ◽  
Cerebellopontine Angle ◽  
Continuous Mapping ◽  
Cost Effective ◽  
Current Intensity ◽  
Vestibular Schwannomas ◽  
Constant Current ◽  
Surgical Workflow ◽  
Ultrasonic Aspirator

Abstract Background Cerebellopontine angle (CPA) surgery carries the risk of lesioning the facial nerve. The goal of preserving the integrity of the facial nerve is usually pursued with intermittent electrical stimulation using a handheld probe that is alternated with the resection. We report our experience with continuous electrical stimulation delivered via the ultrasonic aspirator (UA) used for the resection of a series of vestibular schwannomas. Methods A total of 17 patients with vestibular schwannomas, operated on between 2010 and 2018, were included in this study. A constant-current stimulator was coupled to the UA used for the resection, delivering square-wave pulses throughout the resection. The muscle responses from upper and lower face muscles triggered by the electrical stimulation were displayed continuously on multichannel neurophysiologic equipment. The careful titration of the electrical stimulation delivered through the UA while tapering the current intensity with the progression of the resection was used as the main strategy. Results All operations were performed successfully, and facial nerve conduction was maintained in all patients except one, in whom a permanent lesion of the facial nerve followed a miscommunication to the neurosurgeon. Conclusion The coupling of the electrical stimulation to the UA provided the neurosurgeon with an efficient and cost-effective tool and allowed a safe resection. Positive responses were obtained from the facial muscles with low current intensity (lowest intensity: 0.1 mA). The availability of a resection tool paired with a stimulator allowed the surgeon to improve the surgical workflow because fewer interruptions were necessary to stimulate the facial nerve via a handheld probe.

An appraisal of characteristic mechanical properties and microstructure of friction stir welding for Aluminium 6061 alloy – Silicon Carbide (SiCp) metal matrix composite

2019 ◽  
Vol 13 (4) ◽  
pp. 5804-5817
Author(s):  
Ibrahim Sabry
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Metal Matrix Composite ◽  
Matrix Composite ◽  
Metal Matrix ◽  
Welded Joint ◽  
Rotation Speed ◽  
Fusion Welding ◽  
Friction Stir ◽  
Al 6061

It is expected that the demand for Metal Matrix Composite (MMCs) will increase in these applications in the aerospace and automotive industries sectors, strengthened AMC has different advantages over monolithic aluminium alloy as it has characteristics between matrix metal and reinforcement particles.  However, adequate joining technique, which is important for structural materials, has not been established for (MMCs) yet. Conventional fusion welding is difficult because of the irregular redistribution or reinforcement particles.  Also, the reaction between reinforcement particles and aluminium matrix as weld defects such as porosity in the fusion zone make fusion welding more difficult. The aim of this work was to show friction stir welding (FSW) feasibility for entering Al 6061/5 to Al 6061/18 wt. % SiCp composites has been produced by using stir casting technique. SiCp is added as reinforcement in to Aluminium alloy (Al 6061) for preparing metal matrix composite. This method is less expensive and very effective. Different rotational speeds,1000 and 1800 rpm and traverse speed 10 mm \ min was examined. Specimen composite plates having thick 10 mm were FS welded successfully. A high-speed steel (HSS) cylindrical instrument with conical pin form was used for FSW. The outcome revealed that the ultimate tensile strength of the welded joint (Al 6061/18 wt. %) was 195 MPa at rotation speed 1800 rpm, the outcome revealed that the ultimate tensile strength of the welded joint (Al 6061/18 wt.%) was 165 MPa at rotation speed 1000 rpm, that was very near to the composite matrix as-cast strength. The research of microstructure showed the reason for increased joint strength and microhardness. The microstructural study showed the reason (4 %) for higher joint strength and microhardness.  due to Significant   of SiCp close to the boundary of the dynamically recrystallized and thermo mechanically affected zone (TMAZ) was observed through rotation speed 1800 rpm. The friction stir welded ultimate tensile strength Decreases as the volume fraction increases of SiCp (18 wt.%).

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