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Article
Publication date: 27 September 2023

Markus Brummer, Karl Jakob Raddatz, Matthias Moritz Schmitt, Georg Schlick, Thomas Tobie, Rüdiger Daub and Karsten Stahl

Numerous metals can be processed using the additive manufacturing process laser-based powder bed fusion of metals (PBF-LB/M, ISO/ASTM 52900). The main advantages of additive…

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Abstract

Purpose

Numerous metals can be processed using the additive manufacturing process laser-based powder bed fusion of metals (PBF-LB/M, ISO/ASTM 52900). The main advantages of additive manufacturing technologies are the high degree of design freedom and the cost-effective implementation of lightweight structures. This could be profitable for gears with increased power density, combining reduced mass with considerable material strength. Current research on additively manufactured gears is focused on developing lightweight structures but is seldom accompanied by simulations and even less by mechanical testing. There has been very little research into the mechanical and material properties of additively manufactured gears. The purpose of this study is to investigate the behavior of lightweight structures in additively manufactured gears under static loads.

Design/methodology/approach

This research identifies the static load-carrying capacity of helical gears with different lightweight structures produced by PBF-LB/M with the case hardening steel 16MnCr5. A static gear loading test rig with a maximum torque at the pinion of T1 = 1200 Nm is used. Further focus is set on analyzing material properties such as the relative density, microstructure, hardness depth profile and chemical composition.

Findings

All additively manufactured gear variants show no failure or plastic deformation at the maximum test load. The shaft hub connection, the lightweight hub designs and the gearing itself are stable and intact regarding their form and function. The identified material characteristics are comparable to conventionally manufactured gears (wrought and machined), but also some particularities were observed.

Originality/value

This research demonstrates the mechanical strength of lightweight structures in gears. Future research needs to consider the dynamic load-carrying capacity of additively manufactured gears.

Details

Rapid Prototyping Journal, vol. 29 no. 11
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 10 July 2017

Christian Engelhardt, Jochen Witzig, Thomas Tobie and Karsten Stahl

Water can alter the performance of modern gear lubricants by influencing the flank load carrying capacity of gears significantly. The purpose of this paper is to investigate the…

425

Abstract

Purpose

Water can alter the performance of modern gear lubricants by influencing the flank load carrying capacity of gears significantly. The purpose of this paper is to investigate the influence of water contaminations in different kinds of base oils on the micro-pitting and wear performance of case carburized gears.

Design/methodology/approach

Concerning micro-pitting and wear, tests, based mostly on the following standardized tests, are performed on a Forschungsstelle fuer zahnraeder und getriebebau (FZG)-back-to-back gear test rig: micro-pitting short test Graufleckenkurztest (GFKT) according to DGMK 575 (screening test), micro-pitting test Graufleckentest (GT) according to FVA 54/7 (load stage test and endurance test) and Slow-speed wear test according to DGMK 377. To investigate the effect of water on the gear load carrying capacity dependent on different types of base oils, two polyglycol oils (PG1 and PG2), a polyalphaolefin oil, a mineral oil and an ester oil E are used. Each of these oils are common wind turbine gear oils with a viscosity ISO VG-220. Additionally, a manual transmission fluid with a viscosity of society of automotive engineers (SAE) 75W-85 is tested.

Findings

Considering the micro-pitting and wear performance, a significant decrease caused by water contaminations could not be detected. Regarding pitting damages, a generally negative influence was observed. This influence was differently distinctive for different base oil types. Especially non-polar lubricants seem to be affected negatively. The documented damages of the tooth flanks confirm this observation. While typical pitting damages appeared in test runs with polar lubricants, the disruption in test runs with non-polar lubricants was more extensive. Based on the experimental investigations, a general model of the damaging mechanisms of water contaminations in lubricants was derived. It is split into three partitions: interaction lubricant–water (effect of water on the molecular structure of base oils and additives), chemical-material-technological (especially corrosive reactions) and tribological influence (effect of water droplets in the contact zone). It has to be considered that the additive package of lubricants affects the influence of water contaminations on the flank load carrying capacity distinctively. An influence of water on the micro-pitting and wear performance in other than the given lubricants cannot be excluded.

Originality/value

While former research work was focused more on the effects of water in mineral oils, investigations concerning different types of base oils as well as different types of damages were carried out within this research project.

Details

Industrial Lubrication and Tribology, vol. 69 no. 4
Type: Research Article
ISSN: 0036-8792

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Publication date: 26 November 2019

Marek Jeziński

In this chapter, I discuss the artistic representation of the musical illustration of funeral rites and ceremonies in contemporary Poland. The death of a person in many cultures…

Abstract

In this chapter, I discuss the artistic representation of the musical illustration of funeral rites and ceremonies in contemporary Poland. The death of a person in many cultures is perceived as an important point in the life of a given community, especially a family; hence, people tend to express feelings stemming from these circumstances through art. Songs sung at funerals and during the mourning period have been used for centuries as a way for the living to express their grief for the person who has died. From an anthropological point of view, the main function of music accompanying funeral rites is to help family and friends of the deceased recover from their loss.

To illustrate my argument, I analyse the recording of folk songs by Adam Strug and Kwadrofonik: ‘Requiem Ludowe’ (‘The Folk Requiem’), released on CD in 2013. The musical motifs and lyrical themes are based on original folk tunes of Eastern Poland (Podlasie and Lubelszczyzna regions) that are still used in the villages during the bereavement period. The songs on the CD, which are: ‘Czemu tak rychło, Panie’ (‘Why is it So Soon, my Lord’); ‘Żegnam cię mój świecie wesoły’ (‘Goodbye my Merry World’); ‘Żegnam was mitry i korony’ (‘Goodbye to you Mithra and Crowns’); ‘Żegnam was wszystkie elementa’ (‘Goodbye to you all the Elements’); ‘Powiem prawdę świecie tobie’ (‘I Shall Tell you the Truth, my World’); ‘Piekło’ (‘The Hell’); ‘Czyściec’ (‘The Purgatory’); ‘Niebo’ (‘The Heaven’); and ‘Wieczność’ (‘The Eternity’) are rooted in Christian funeral traditions and they are supplemented by elements of Slavic folklore.

The lyrics of the mourning songs published on the recording display a specific attitude to the mythology of death and bereavement present in the culture of Polish peasants. The main themes of these folk songs, namely, the praise of the deceased, the grief of the remaining family, the preparation of the dead one for eternal life or the attempts to cross the threshold of life and death, are presented by the artists as the soul’s journey from the Earth to the Underworld, and through Purgatory to Eternal life as a final stage of a person’s destination. They show how the rural people imagine death itself and express their feelings of loss and grief in art to overcome the fear of the unknown.

Details

Music and Death: Interdisciplinary Readings and Perspectives
Type: Book
ISBN: 978-1-83867-945-3

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Article
Publication date: 8 February 2011

Markus Klein, Bernd‐Robert Höhn, Klaus Michaelis and Rainer Annast

A failure mode called “flank breakage” is increasingly observed in cylindrical and bevel gears. Up to now, there was no calculation method available to determine the load‐carrying…

669

Abstract

Purpose

A failure mode called “flank breakage” is increasingly observed in cylindrical and bevel gears. Up to now, there was no calculation method available to determine the load‐carrying capacity related to flank breakage in bevel gears. Therefore, a research project was initiated to investigate the described failure mode in bevel gears and to develop a calculation method to predict the risk of flank breakage of such gears. The purpose of this paper is to describe this project.

Design/methodology/approach

The presented research project contained: determination of the decisive influence parameters in experimental investigations with bevel gears; development of a model to explain flank breakage in bevel gears; and development of a calculation method and design rules to avoid flank breakage.

Findings

In systematic tests, the influenced parameters of flank breakage were investigated. Besides the load torque, especially the case depth and the core hardness turned out as decisive parameters. A higher sulfur concentration in the material does not seem to be critical. The analysis of damage patterns of test and practical gears showed that the initiating crack always started below the surface in the region of the transition from case to core. For unidirectional loading, the crack propagates to the active flank on the one side and to the tooth root on the other side. On the basis of these findings, a local and a simplified calculation method were developed to estimate the risk of flank breakage.

Originality/value

With the described calculation method, it is now possible to evaluate running gears according to their risk of flank breakage and design new gears with a sufficient safety factor to avoid this failure.

Details

Industrial Lubrication and Tribology, vol. 63 no. 1
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 1 April 1908

THE fact that an English librarian was asked to describe the work of British municipal libraries, to audiences in Antwerp and Brussels, may be taken as a certain indication that a…

40

Abstract

THE fact that an English librarian was asked to describe the work of British municipal libraries, to audiences in Antwerp and Brussels, may be taken as a certain indication that a change is impending in the library world of Belgium. At the invitation of M. Frans Gittens, city librarian, Antwerp, acting on behalf of the Foundation for the Permanent Endowment of the Communal Library and Plantin‐Moretus Museum, and M. Paul Otlet, secretary‐general of the International Institute of Bibliography, Brussels, I had the honour and pleasure of lecturing on English library work and conditions to representative audiences greatly interested in the subject. This, it is understood, is the first time an English librarian has been invited to lecture on such a subject on any part of the Continent, and I certainly felt it a great honour and privilege to be thus selected for such a congenial task. The language difficulty was luckily no great bar, as most of my audiences, both Flemish and French, understood English quite well. In addition, the International Institute of Bibliography had printed a translation of the lecture, as No. 92 of its publications, and this was issued as a twenty‐two page pamphlet entitled Les Bibliothèques municipales en Angleterre, and distributed at Brussels. At Antwerp the programme also contained translations of the titles and remarks about the lantern slides, so that everything was made easy for one who has always deplored his inability to acquire the art of speaking foreign languages. As a further instance of the care and thoughtfulness exercised to provide for my comfort, I should acknowledge the kindness of M. Eugeen Everaerts, town librarian of Ostend, who, on representations from his colleague at Antwerp, met the steamer and passed me and my “projections” through the Custom House without trouble. There is no doubt that our Belgian friends have the knack of making strangers feel thoroughly at home. I am not likely to forget the kindness and hospitality of M. W. von Mallinckrodt, chairman of the Permanent Endowment Commission at Antwerp, who, with his charming wife, invited me to a lunch at which some of the chief residents were present, including Sir Cecil Hertslet, H.B.M. Consul‐General; Mr. Diedrich, the American Consul‐General; M. Henri Hymans, chief librarian of the Royal Library at Brussels; M. Max Rooses, of the Plantin Museum; M. Frans Gittens, with some members of his staff; and other gentlemen connected with the city and municipality of Antwerp. The same kindly hospitality was extended by M. Gittens, of Antwerp, and M. Otlet, at Brussels, and everything was done by all with whom I came in contact to make me feel at ease and nothing of a stranger. In fact it is impossible for anyone who has read Scott, Brontë and Conscience to feel like a stranger in Belgium. The lecture at Antwerp was given in the large and finely decorated hall of the Cercle Royal Artistique, Littéraire et Scientifique d'Anvers, a kind of general Arts Club combining the functions of places like the London Institution with those of an ordinary social club. The hall was capable of seating 1,000 persons, and was rather beyond my poor powers as an elocutionist. About 600 people attended, of whom a large number understood English, and my lecture, luckily for my audience, largely pictorial, was very well received. There was no preliminary introduction of any kind, and my “turn” came on after a concert had been about half heard. The following programme will give an idea of the kind of mixed entertainment which brought out 600 people on a snowy winter's afternoon:—

Details

New Library World, vol. 10 no. 10
Type: Research Article
ISSN: 0307-4803

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Article
Publication date: 19 July 2019

Andreas Ziegltrum, Stefan Emrich, Thomas Lohner, Klaus Michaelis, Alexander Brodyanski, Rolf Merz, Michael Kopnarski, Bernd-Robert Hoehn and Karsten Stahl

This paper aims to address the influence of tribofilms and running-in on failures and friction of gears. The operation regime of gears is increasingly shifted to mixed and…

278

Abstract

Purpose

This paper aims to address the influence of tribofilms and running-in on failures and friction of gears. The operation regime of gears is increasingly shifted to mixed and boundary lubrication, where high local pressures and temperatures occur at solid interactions in the gear contact. This results in strong tribofilm formation due to interactions of lubricant and its additives with the gear flanks and is related to changes of surface topography especially pronounced during running-in.

Design/methodology/approach

Experiments at a twin-disk and gear test rig were combined with chemical, structural and mechanical tribofilm characterization by surface analysis. Pitting lifetime, scuffing load carrying capacity and friction of ground spur gears were investigated for a mineral oil with different additives.

Findings

Experimental investigations showed a superordinate influence of tribofilms over surface roughness changes on damage and friction behavior of gears. Surface analysis of tribofilms provides explanatory approaches for friction behavior and load carrying capacity. A recommendation for the running-in of spur gears was derived.

Originality/value

Experimental methods and modern surface analysis were combined to study the influence of running-in and tribofilms on different failures and friction of spur gears.

Details

Industrial Lubrication and Tribology, vol. 71 no. 8
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 12 May 2021

Kirsten Bobzin, Tobias Brögelmann, Christian Kalscheuer, Matthias Thiex, Andreas Schwarz, Martin Ebner, Thomas Lohner and Karsten Stahl

This paper aims to address the coating and compound analysis of diamond-like carbon (DLC) on steel, to understand the frictional behavior in tribological gear systems presented in…

280

Abstract

Purpose

This paper aims to address the coating and compound analysis of diamond-like carbon (DLC) on steel, to understand the frictional behavior in tribological gear systems presented in paper Part I. Here, the Ti and Zr modified DLC coating architectures are analyzed regarding their chemical, mechanical and thermophysical properties. The results represent a systematic analysis of the thermal insulating effect in tribological contact of DLC coated gears.

Design/methodology/approach

The approach was to evaluate the effect of the substitution of Zr through Ti at the reference coating ZrCg to TiCg and the effect on thermophysical properties. Furthermore, the influence of different carbon and hydrogen contents on the coating and compound properties was analyzed. Therefore, different discrete Ti or Zr containing DLC coatings were deposited on an industrial coating machine. Thereby the understanding of the microstructure and chemical composition of the reference coatings is increased.

Findings

Results prove comparable mechanical properties of metal modified DLC independent of differences in chemical compositions. Moreover, the compound adhesion between TiCg/16MnCr5E was improved compared to ZrCg/16MnCr5E. The effect of hydrogen content Ψ and carbon content xc on the thermophysical properties is limited by Ψ = 18 at.% and xc = 90 at.%.

Practical implications

The findings of the combined papers Part I and II show a high potential for industrial application of DLC on gears. Based on the results DLC coatings and gears can be tailored to each other.

Originality/value

Systematic analysis of DLC coatings were conducted to evaluate the effect of titanium, carbon and hydrogen on thermophysical properties.

Details

Industrial Lubrication and Tribology, vol. 73 no. 4
Type: Research Article
ISSN: 0036-8792

Keywords

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