scholarly journals Operating behavior and performance of oil-lubricated plastic gears

2021 ◽  
Author(s):  
C. M. Illenberger ◽  
T. Tobie ◽  
K. Stahl
Keyword(s):  
Material Properties ◽  
Load Capacity ◽  
Research Work ◽  
Experimental Studies ◽  
Experimental Investigations ◽  
Market Shares ◽  
Large Numbers ◽  
And Performance ◽  
Tooth Flank ◽  
Plastic Gears

AbstractPlastic gears and their numerous applications have become an integral part of industrial practice. In particular, the ability to produce large numbers of gears cost-effectively using injection molding techniques is making a significant contribution to growing market shares. Compared to conventional steel materials, however, the material properties of thermoplastics differ fundamentally. In particular, the high temperature dependence of the material properties and the lower strength pose challenges for designers. Against this background, theoretical and experimental studies on the operating and service life behavior of different thermoplastic materials have been conducted and evaluated. In addition to theoretical investigations on the tooth flank load carrying capacity, comprehensive measurements on temperature behavior were carried out and compared to common methods of temperature calculation for plastic gears. Experimental investigations on the tooth flank load capacity by means of back-to-back tests of different materials and their evaluation show the potential of thermoplastic materials for the application in power transmitting drivetrains. This contribution will give an overview of the performed research work and summarizes main results of these studies.

Machine for the Hydrostatic Extrusion–Drawing of Wire

1972 ◽  
Vol 186 (1) ◽  
pp. 499-507
Author(s):  
H. Ll. D. Pugh ◽  
P. T. Wilkinson ◽  
M. H. Hodge
Keyword(s):  
Copper Wire ◽  
Research Work ◽  
Hydrostatic Extrusion ◽  
Experimental Results ◽  
Experimental Investigations ◽  
Small Scale ◽  
New Process ◽  
And Performance ◽  
Commercial Applications ◽  
Fine Copper

Research work on hydrostatic extrusion at N.E.L. (National Engineering Laboratory) has led to the development of a new process for producing wire. A detailed account is given of machines specially designed to exploit this process of hydrostatic extrusion–drawing mainly on the production of fine copper wire. A small-scale machine was built to confirm the design and for experimental investigations. The success of this preliminary work has led to the construction of a large prototype production machine for commercial applications. The operation and performance of both machines is described and some experimental results given.

Composite Fabric Blankets for Plastic Gears

2018 ◽  
Author(s):  
S. Kini ◽  
A. Fuentes Aznar ◽  
H. Ghoneim
Keyword(s):  
Gear Tooth ◽  
Load Capacity ◽  
Research Work ◽  
Maximum Level ◽  
Contact Stresses ◽  
Composite Surface ◽  
Tooth Surfaces ◽  
Bending Stresses ◽  
Future Work ◽  
Plastic Gears

Two approaches for increasing the load capacity of plastic gears in general are proposed and investigated: modifying the conventional involute profile of the gear tooth surfaces by applying a parabolic-crowned profile, and introducing a composite fabric, which blankets the surface of the teeth. The investigation is carried out using the finite element method (IGD/ANSYS). A five-tooth model is applied for the gears, and nylon and carbon/nylon are adopted for the materials. The evolution of maximum contact and bending stresses is evaluated over two cycles of meshing for both the pure plastic (nylon) gears and the gears with the composite surface blanket (carbon/nylon) to investigate the process of transfer of load between consecutive pairs of teeth and detect possible edge contacts. The results indicate that selecting the proper parabolic-crowned profile helps to alleviate the contact stress, and more specifically, to reduce the peaks of contact stresses due to edge contacts at the tip of the teeth. The results also indicate that there are an optimum parabolic-crowned profile and an optimum thickness of the composite blanket, which render the lowest maximum level of contact stresses over the cycle of meshing and bending stresses at the fillet. However, this preliminary research work suggests that, for the case considered, the novel idea of composite blanket is inconclusive — though the blanket may protect the plastic core, it itself becomes vulnerable to failure. The idea is being explored more, and the results will be disseminated in a future work.

On Experimental Studies of Longitudinal and Flexural Wave Propagations: An Annotated Bibliography

1986 ◽  
Vol 39 (6) ◽  
pp. 853-865 ◽  
Author(s):  
M. M. Al-Mousawi
Keyword(s):  
Wave Propagation ◽  
Cross Section ◽  
Material Properties ◽  
Experimental Studies ◽  
Flexural Wave ◽  
Experimental Investigations ◽  
Velocity Impact ◽  
Flexural Wave Propagation ◽  
The Impact

Experimental investigations in the field of longitudinal wave propagation in beams are plentiful; however, experimental studies of flexural wave propagation problems are scarce and are restricted mainly to uniform and infinite structures where the effects of reflected waves are not generally included. This review is mostly restricted to low velocity impact and does not cover the so-called high velocity impact such as those of bullets and explosives. In addition to a brief survey of classical work related to impact, this article covers publications related to experimental studies of longitudinal and flexural elastic waves due to impact. This includes the longitudinal, central as well as eccentric impact and transverse impact of two bars and the impact achieved by sphere impinging on a beam. Many workers used experimental findings to study the adequacy of various theoretical solutions of the wave propagation problem such as those by Pochhammer and Chree, Euler–Bernoulli, and the Timoshenko beam theory. The revival of interest in the recent years is due to, among other things, the advancement of experimental equipment and measurement techniques for data acquisition of stress waves and associated signals. An important application of transient waves is their use for the determination of material properties under various loading conditions and strain rates that can be studied by the split Hopkinson pressure bar techniques. The problem of longitudinal and flexural waves in bars with discontinuities of cross section are covered, and some publications on fracture of materials due to bending waves are also included. Experimental investigations demonstrate the effect of abrupt change of cross section and/or material properties on reflected and transmitted waves where reflections are to be taken into consideration when estimating the level of stresses and strains in finite beam with discontinuities. In the field of flexural wave propagation, comparison of theoretical predictions with experimental results verified and validated the adequacy of the Timoshenko theory for the determination of bending strain in finite structures, a one-dimensional theory that takes into account the effect of shear deformation and rotatory inertia.

ANTECEDENTS AND CONSEQUENCES OF ORGANIZATIONAL JUSTICE

2016 ◽  
Vol 12 (02) ◽  
Author(s):  
Reeta Yadav
Keyword(s):  
Job Satisfaction ◽  
Organizational Justice ◽  
Organizational Citizenship ◽  
Organizational Citizenship Behavior ◽  
Turnover Intentions ◽  
Research Work ◽  
Citizenship Behavior ◽  
Future Research ◽  
Antecedents And Consequences ◽  
And Performance

Employee’s perception regarding fairness in the organization is termed as organizational justice. The objective of this paper is to study the antecedents and consequences of organizational justice on the basis of earlier relevant studies from the period ranging from 1964 to 2015. Previous research identified employee participation, communication, justice climate as the antecedents and trust, job satisfaction, commitment, turnover intentions, organizational citizenship behavior and performance as the consequences of organizational justice. Finding reveals the gaps existing in the literature and gives suggestions for future research work.

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.

scholarly journals Experimental investigations on diesel engine using alumina nanoparticle fuel additive

2021 ◽  
Vol 13 (2) ◽  
pp. 168781402098840
Author(s):  
Mohammed S Gad ◽  
Sayed M Abdel Razek ◽  
PV Manu ◽  
Simon Jayaraj
Keyword(s):  
Diesel Engine ◽  
Diesel Fuel ◽  
Alumina Nanoparticles ◽  
Experimental Investigations ◽  
Fuel Additive ◽  
Alumina Nanoparticle ◽  
Fuel Injectors ◽  
Performance And Emission ◽  
And Performance ◽  
The Impact

Experimental work was done to examine the impact of diesel fuel with alumina nanoparticles on combustion characteristics, emissions and performance of diesel engine. Alumina nanoparticles were mixed with crude diesel in various weight fractions of 20, 30, and 40 mg/L. The engine tests showed that nano alumina addition of 40 ppm to pure diesel led to thermal efficiency enhancement up to 5.5% related to the pure diesel fuel. The average specific fuel consumption decrease about neat diesel fuel was found to be 3.5%, 4.5%, and 5.5% at dosing levels of 20, 30, and 40 ppm, respectively at full load. Emissions of smoke, HC, CO, and NOX were found to get diminished by about 17%, 25%, 30%, and 33%, respectively with 40 ppm nano-additive about diesel operation. The smaller size of nanoparticles produce fuel stability enhancement and prevents the fuel atomization problems and the clogging in fuel injectors. The increase of alumina nanoparticle percentage in diesel fuel produced the increases in cylinder pressure, cylinder temperature, heat release rate but the decreases in ignition delay and combustion duration were shown. The concentration of 40 ppm alumina nanoparticle is recommended for achieving the optimum improvements in the engine’s combustion, performance and emission characteristics.

scholarly journals A FEM-Based 2D Model for Simulation and Qualitative Assessment of Shot-Peening Processes

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2784
Author(s):  
Georgios Maliaris ◽  
Christos Gakias ◽  
Michail Malikoutsakis ◽  
Georgios Savaidis
Keyword(s):  
Process Parameters ◽  
Material Properties ◽  
Shot Peening ◽  
Qualitative Assessment ◽  
Experimental Investigations ◽  
Elastoplastic Material ◽  
Size Distributions ◽  
User Friendly ◽  
The Impact ◽  
2D Model

Shot peening is one of the most favored surface treatment processes mostly applied on large-scale engineering components to enhance their fatigue performance. Due to the stochastic nature and the mutual interactions of process parameters and the partially contradictory effects caused on the component’s surface (increase in residual stress, work-hardening, and increase in roughness), there is demand for capable and user-friendly simulation models to support the responsible engineers in developing optimal shot-peening processes. The present paper contains a user-friendly Finite Element Method-based 2D model covering all major process parameters. Its novelty and scientific breakthrough lie in its capability to consider various size distributions and elastoplastic material properties of the shots. Therewith, the model is capable to provide insight into the influence of every individual process parameter and their interactions. Despite certain restrictions arising from its 2D nature, the model can be accurately applied for qualitative or comparative studies and processes’ assessments to select the most promising one(s) for the further experimental investigations. The model is applied to a high-strength steel grade used for automotive leaf springs considering real shot size distributions. The results reveal that the increase in shot velocity and the impact angle increase the extent of the residual stresses but also the surface roughness. The usage of elastoplastic material properties for the shots has been proved crucial to obtain physically reasonable results regarding the component’s behavior.

A study of factors which influence the job satisfaction of stockpeople on commercial pig farms

1990 ◽  
Vol 1990 ◽  
pp. 95-95
Author(s):  
R C Segundo ◽  
P R English ◽  
G Burgess ◽  
S A Edwards ◽  
O MacPherson ◽  
...  
Keyword(s):  
Job Satisfaction ◽  
Reproductive Performance ◽  
Research Work ◽  
Farm Animals ◽  
Considerable Influence ◽  
Pig Farms ◽  
And Performance ◽  
The Uk ◽  
Farm Livestock

The role of stockmanship in relation to the wellbeing of farm animals has been emphasised in the UK Codes of Recommendations for the Welfare of Farm Livestock (MAFF, 1983). Moreover, previous research work has demonstrated important effects of good and bad stockmanship not only on welfare but also on growth, lactational and reproductive performance of pigs and other farm livestock (Hemsworth et al, 1987). There is a need, therefore, to establish the factors which motivate and demotivate stockpeople since the degree of job satisfaction is likely to have a considerable influence on the attitude and performance of stockpeople and on their empathy with the animals in their care. With this objective in mind, a questionnaire was designed to investigate the aspects which could have an influence on the job satisfaction of the stockpeople involved in pig production.

Numerical and experimental studies on the thermal and static characteristics of multi-leaf foil thrust bearing

2021 ◽  
pp. 135065012110110
Author(s):  
Yu Guo ◽  
Yu Hou ◽  
Qi Zhao ◽  
Xionghao Ren ◽  
Shuangtao Chen ◽  
...  
Keyword(s):  
High Speed ◽  
Thrust Bearing ◽  
Load Capacity ◽  
Failure Process ◽  
Experimental Studies ◽  
Elastic Model ◽  
Static Characteristics ◽  
Bearing Load ◽  
Foil Thrust Bearing ◽  
Cooling Air

Foil bearing is considered to be a promising supporting technology in high-speed centrifugal machinery. Due to the high-speed shearing effect in the viscous lubricant film, heat generation could not be ignored. In this paper, a thermo-elastic model of the multi-leaf foil thrust bearing is proposed to predict its thermal and static characteristics. In the model, modified Reynolds equation, energy equation, and Kirchhoff equation are solved in a coupling way. The contact area between the foil and welding plate is taken into account. Besides, the effect of cooling air on the bearing temperature is investigated. The ultimate load capacity and transient overload failure process of the bearing is analyzed and discussed. The effect of rotation speed on the bearing temperature is more obvious than that of the bearing load. The bearing temperature drops obviously by introducing the cooling air, and the cooling effect is improved with the supply pressure. The transient overload failure of the bearing occurs when the bearing load exceeds the ultimate value.

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