scholarly journals Nonsmooth Vibration Characteristic of Gear Pair System with Periodic Stiffness and Backlash

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Minjia He ◽  
Shuo Li ◽  
Zhenjun Lin ◽  
Jinjin Wang ◽  
Shuang Liu ◽  
...  
Keyword(s):  
Bifurcation Diagram ◽  
Power Transmission ◽  
Vibration Characteristics ◽  
Practical Significance ◽  
Mechanical Equipment ◽  
Gear Pair ◽  
Periodic Response ◽  
Discontinuity Mapping ◽  
Set Up ◽  
Sliding Dynamics

As the most widely used power transmission device in mechanical equipment, the vibration characteristics of gears have a very important influence on the working performance. It is of great theoretical and practical significance to study the vibration characteristics of gear system. In this paper, a gear transmission system model is set up in a forcefully nonlinear form; the continuity mapping and discontinuity mapping are utilized to analyze the nonsmooth vibration. Then, the sliding dynamics of separation boundaries is studied by using the perturbation method and the differential inclusion theory. In addition, the periodic response of gear pair system is illustrated and Floquet’s theory is presented to confirm the stability and bifurcation of periodic response. Concurrently, the maximal Lyapunov exponent is obtained to accurately determine the chaotic state in gear pair system, which is consistent with the bifurcation diagram and Poincare section. Finally, a reasonable explanation is given for the jump phenomenon in bifurcation diagram.

scholarly journals Synthesis of the Sparse Uniform-Amplitude Concentric Ring Transmitting Array for Optimal Microwave Power Transmission

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Hua-Wei Zhou ◽  
Xue-Xia Yang ◽  
Sajjad Rahim
Keyword(s):  
Microwave Power ◽  
Large Scale ◽  
Power Transmission ◽  
Synthesis Method ◽  
Pso Algorithm ◽  
Practical Significance ◽  
Concentric Ring ◽  
Swarm Optimization ◽  
Key Factor ◽  
Feed Network

Beam capture efficiency (BCE) is one key factor of the overall efficiency for a microwave power transmission (MPT) system, while sparsification of a large-scale transmitting array has a practical significance. If all elements of the transmitting array are excited uniformly, the fabrication, maintenance, and feed network design would be greatly simplified. This paper describes the synthesis method of the sparse uniform-amplitude transmitting array with concentric ring layout using particle swarm optimization (PSO) algorithm while keeping a higher BCE. Based on this method, uniform exciting strategy, reduced number of elements, and a higher BCE are achieved simultaneously for optimal MPT. The numerical results of the sparse uniform-amplitude concentric ring arrays (SUACRAs) optimized by the proposed method are compared with those of the random-located uniform-amplitude array (RLUAA) and the stepped-amplitude array (SAA), both being reported in the literatures for the maximum BCE. Compared to the RLUAA, the SUACRA saves 32% elements with a 1.1% higher BCE. While compared to the SAA, the SUACRA saves 29.1% elements with a bit higher BCE. The proposed SUACRAs have higher BCEs, simple array arrangement and feed network, and could be used as the transmitting array for a large-scale MPT system.

Application of Cascade-Correlation Algorithm in Vibration Characteristics of Hydro Turbine

2010 ◽  
Vol 108-111 ◽  
pp. 1070-1074
Author(s):  
Li Ying Wang ◽  
Wei Guo Zhao ◽  
Jian Min Hou
Keyword(s):  
Bp Neural Network ◽  
Learning Algorithm ◽  
Optimal Operation ◽  
Vibration Characteristics ◽  
Bp Algorithm ◽  
Practical Significance ◽  
Hydro Turbine ◽  
Correlation Algorithm ◽  
Cascade Correlation ◽  
Better Than

The cascade correlation algorithm that is CC algorithms, CC network structure and CC network weights learning algorithm are introduced, based on the operation data of Wanjiazhai hydropower station, considering the pressure fluctuation, the network model of vibration characteristics is established based on CC algorithm, and the applications of CC and BP algorithm in vibration characteristics of turbine are compared. The results show that the CC algorithm is better than BP neural network, the results can be used in the optimal operation of hydropower, and it has a practical significance.

Characterization of Nonlinear Rattling Behavior of a Gear Pair Through a Validated Torsional Model

2021 ◽  
Author(s):  
Ata Donmez ◽  
Ahmet Kahraman
Keyword(s):  
Piecewise Linear ◽  
Nonlinear Behavior ◽  
Severity Index ◽  
System Response ◽  
Gear Pair ◽  
Computationally Efficient ◽  
Linear Solution ◽  
Set Up ◽  
The Impact ◽  
Gear Rattle

Abstract Dynamic response of a gear pair subjected to input and output torque or velocity fluctuations is examined analytically. Such motions are commonly observed in various powertrain systems and identified as gear rattle or hammering motions with severe noise and durability consequences. A reduced-order torsional model is proposed along with a computationally efficient piecewise-linear solution methodology to characterize the system response including its sensitivity to excitation parameters. Validity of the proposed model is established through comparisons of its predictions to measurements from a gear rattle experimental set-up. A wide array of nonlinear behavior is demonstrated through presentation of periodic and chaotic responses in the forms of phase plots, Poincaré maps, and bifurcation diagrams. The severity of the resultant impacts on the noise outcome is also assessed through a rattle severity index defined by using the impact velocities.

scholarly journals Bearing Health Monitoring Based on the Orthogonal Empirical Mode Decomposition

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
C. Delprete ◽  
E. Brusa ◽  
C. Rosso ◽  
F. Bruzzone
Keyword(s):  
Empirical Mode Decomposition ◽  
Power Transmission ◽  
Vibration Signal ◽  
Power Transmission Line ◽  
Industrial Equipment ◽  
Test Rig ◽  
Service Monitoring ◽  
Mode Decomposition ◽  
Crucial Component ◽  
Set Up

Bearing is a crucial component of industrial equipment, since any fault occurring in this system usually affects the functionality of the whole machine. To manage this problem, some currently available technologies enable the remote prognosis and diagnosis of bearings, before that faults compromise the system function and safety, respectively. A system for the in-service monitoring of bearing, to detect any inner fault or damage of components and material, allows preventing undesired machine stops. Moreover, it even helps in performing an out-monitoring action, aimed at revealing any anomalous behaviour of the system hosting bearings, through their dynamic response. The in-monitoring can be based on the vibration signal measurement and exploited to detect the presence of defects in material. In this paper, the orthogonal empirical mode decomposition is analysed and tested to investigate how it could be effectively exploited in a lean in-service monitoring operation and remote diagnosis. The proposed approach is validated on a test rig, where an elementary power transmission line was set up. The activity highlights some main properties and practical issues of the technological implementation, as well as the precision of the Orthogonal Empirical Mode Decomposition, as a compact approach for an effective detection of bearing faults in operation.

Gregory of Nyssa's Dialogue with Macrina

2005 ◽  
Vol 62 (2) ◽  
pp. 210-222
Author(s):  
John L. Drury
Keyword(s):  
The Body ◽  
Christian Theology ◽  
Practical Significance ◽  
False Dichotomy ◽  
Common Objection ◽  
The Common ◽  
Set Up ◽  
Immortality Of The Soul

Through an analysis of Gregory of Nyssa's treatise On the Soul and the Resurrection, this article argues for the compatibility of the doctrines of the immortality of the soul and the resurrection of the body. Nyssa's view is explicitly contrasted to contemporary tendencies to set up a false dichotomy between the two doctrines. After answering the common objection that immortality is an intruder to Christian theology, a typology of four views on the relation between immortality and resurrection is set out. The article concludes with reflections on the theological and practical significance of Gregory's view.

A MOBILE PLANT PROTOTYPE FOR THE RESTORATION OF POLLUTED BEACHES BY WASHING OILY SAND

1987 ◽  
Vol 1987 (1) ◽  
pp. 61-65
Author(s):  
Christian Bocard ◽  
Jean-Jacques Quinquis ◽  
Christian Such
Keyword(s):  
European Economic Community ◽  
Fuel Oil ◽  
Wash Water ◽  
Mechanical Equipment ◽  
Heavy Fuel Oil ◽  
Cleaning Agents ◽  
Pilot Trials ◽  
Mobile Plant ◽  
Recreational Beaches ◽  
Set Up

ABSTRACT A research program was undertaken in 1980 with the support of the European Economic Community and the French Ministry of the Environment to develop a technique for treating beaches polluted by an oil spill, after the bulk of the oil has been removed from the surface of the sand by mechanical equipment. Final cleanup is often necessary, especially in the case of recreational beaches, when the oil remaining in the upper layer of sand—frequently in the range of 2 to 3 percent—in unacceptable. There is some controversy regarding the use of dispersants for this purpose. The basic principle of the technique is to wash oil-contaminated sand in transportable equipment which is operated either close to the polluted beach or at a centralized location, the washed sand then being returned to the beach or used for other purposes. The selected equipment and three different cleaning agents were tested in pilot trials carried out on sand polluted with heavy fuel oil. A plant prototype was set up and tested in 1985. It is composed mainly of a horizontally rotating wash drum associated with a screen, a hydrocyclone to separate the sand from the wash-water phase and a vibrating screen for sand dewatering. These three pieces of equipment are mounted on the bed of a semi-trailer along with two transfer pumps. Oil and sand fines are separated from the water, before recycling, in several ground tanks in which a flocculating agent may be added. The operating parameters of the process are discussed on the basis of trials carried out at a throughput of 18 metric tons of sand per hour, giving a washed sand with an average oil content of 0.2 percent in the case of moderate weathering.

The Research of Humanized Design of Mechanical Equipment

2012 ◽  
Vol 201-202 ◽  
pp. 890-893
Author(s):  
Jian Wei Pan
Keyword(s):  
Product Design ◽  
Rational Functions ◽  
Design Concept ◽  
Practical Significance ◽  
Mechanical Equipment ◽  
Human Needs ◽  
Equipment Safety ◽  
Basic Functions ◽  
Machine Communication ◽  
Equipment Operator

The requirements of modern industrial mechanical equipment not only stay in the realization of its basic functions, but pay more attention to issues of the humanized design involved in product design. During the design process of mechanical equipment, the pursuit of rational functions, the full consideration to human needs, the formation of efficient human-machine communication, and the improving of the product quality are the significances of the humanized design. Therefore, the studying of the humanized design of mechanical equipment not only has its theoretical significance, but also has very important practical significance. The application of humanized design concept in mechanical product design is analyzed and researched in this paper. It is necessarily demonstrated humanization design concept applied to mechanical equipment product design from mechanical equipment safety, easy operation, form, color, mechanical equipment operator mental model five aspects.

scholarly journals A Multiobjective Optimization Analysis of Spur Gear Pair: The Profile Shift Factor Effect on Structure Design and Efficiency

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Samya Belarhzal ◽  
Kaoutar Daoudi ◽  
El Mostapha Boudi ◽  
Aziz Bachir ◽  
Samira Elmoumen
Keyword(s):  
Multiobjective Optimization ◽  
Power Transmission ◽  
Spur Gear ◽  
Shift Factor ◽  
Structure Design ◽  
Operating Conditions ◽  
Gear Pair ◽  
Contact Ratio ◽  
Face Width ◽  
Volume Equation

Spur gears are an indispensable element of power transmission, most of the time used in small environments with severe operating conditions such as high temperature, vibrations, and humidity. For this reason, manufacturers and transmission designers are required to look for better gear designs and higher efficiency. In this paper, a multiobjective optimization was conducted, using genetic algorithms (GAs) for corrected spur gear pair with an objective to reduce the structure volume and transmission power loss and reveal the influence of the profile shift factor on the optimal structure fitness. The optimization variables included are the pinion and wheel profile shift factors in addition to the module, face width, and the number of pinion teeth mostly used in standard gear optimization. The profile shift factor influences the shape of the gear teeth, the contact ratio, and the load sharing. It affects then the optimal results meaningfully. The gear pair volume, center distance, and efficiency presented the objective functions while contact stress, bending stress, face with coefficient, and tooth tip interferences served as constraints. Furthermore, a volume equation was developed, in which a bottom clearance formula is included for more accurate results. "Multiobjective optimization" is conducted at medium and high speeds, and the results show that the structure design is compact compared to standard gears with reasonable efficiency for medium contact ratio.

scholarly journals Evaluation of Food Fineness by the Bionic Tongue Distributed Mechanical Testing Device

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4250
Author(s):  
Jingjing Liu ◽  
Ying Cui ◽  
Yizhou Chen ◽  
Wei Wang ◽  
Yuanyuan Tang ◽  
...  
Keyword(s):  
Mechanical Testing ◽  
Evaluation Model ◽  
Areal Density ◽  
Practical Significance ◽  
Testing Device ◽  
Tongue Movements ◽  
Tongue Surface ◽  
Mechanical Information ◽  
Set Up

In this study, to obtain a texture perception that is closer to the human sense, we designed eight bionic tongue indenters based on the law of the physiology of mandibular movements and tongue movements features, set up a bionic tongue distributed mechanical testing device, performed in vitro simulations to obtain the distributed mechanical information over the tongue surface, and preliminarily constructed a food fineness perception evaluation model. By capturing a large number of tongue movements during chewing, we analyzed and simulated four representative tongue movement states including the tiled state, sunken state, raised state, and overturned state of the tongue. By analyzing curvature parameters and the Gauss curvature of the tongue surface, we selected the regional circle of interest. With that, eight bionic tongue indenters with different curvatures over the tongue surface were designed. Together with an arrayed film pressure sensor, we set up a bionic tongue distributed mechanical testing device, which was used to do contact pressure experiments on three kinds of cookies—WZ Cookie, ZL Cookie and JSL Cookie—with different fineness texture characteristics. Based on the distributed mechanical information perceived by the surface of the bionic tongue indenter, we established a food fineness perception evaluation model by defining three indicators, including gradient, stress change rate and areal density. The correlation between the sensory assessment and model result was analyzed. The results showed that the average values of correlation coefficients among the three kinds of food with the eight bionic tongue indenters reached 0.887, 0.865, and 0.870, respectively, that is, a significant correlation was achieved. The results illustrate that the food fineness perception evaluation model is effective, and the bionic tongue distributed mechanical testing device has a good practical significance for obtaining food texture mouthfeel information.

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