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    <title>Transport Research International Documentation (TRID)</title>
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>Transport Research International Documentation (TRID)</title>
      <url>https://trid.trb.org/Images/PageHeader-wTitle.jpg</url>
      <link>https://trid.trb.org/</link>
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    <item>
      <title>TEST ON MARINE REDUCTION GEAR BY MEANS OF A LARGE TEST RIG</title>
      <link>https://trid.trb.org/View/167400</link>
      <description><![CDATA[Results of load tests on large reduction gears tested on a testing machine having a centre distance of 720mm are described.  Non-modified shaved gears failed after K=350 psi load run at 100 million cycles.  Modified shaved gears failed after K=400 psi load run at 50 million cycles.  In addition the paper deals with the tooth load distributions by measuring the stress in the root fillet, temperature difference between gear and pinion, and temperature distributions on the tooth face.  Order from NSFI as No. 22437.]]></description>
      <pubDate>Fri, 12 Jun 1981 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/167400</guid>
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    <item>
      <title>VIBRATION PROBLEMS WITH LARGE REDUCTION GEARS IN MARINE ENGINES</title>
      <link>https://trid.trb.org/View/161217</link>
      <description><![CDATA[Torsional vibrations are a source of considerable dynamic problems in drive units, particularly those equipped with reduction gears.  For the evaluation of these vibrations, the gearing cannot be regarded as an independent unit, but must be treated together with its associated propulsion systems, drive shafts and couplings as a coherent, vibration-susceptible system.  From the point of view of a manufacturer of large reduction gears, this paper deals with some special problems that have occurred and for which solutions have been devised in practice.  The gear manufacturer should be prepared to clearly indicate permissible vibratory torques in dynamic load diagrams.  In marine diesel propulsion units, particular care is required when misfiring of a cylinder or when malfunction of a governor is encountered.  Branched systems with multi-engine input or with auxiliary outputs for generators cause additional problems.  A method for measuring the dynamic load directly at the gear teeth by means of strain gauges is recommended for the determination of stress distributions in doubtful cases.]]></description>
      <pubDate>Thu, 12 Mar 1981 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/161217</guid>
    </item>
    <item>
      <title>MARINE GEARING</title>
      <link>https://trid.trb.org/View/151657</link>
      <description><![CDATA[This book outlines the many advances which have taken place in the development of modern marine gearing and updates gear design, construction, installation and operation. Comprehensive treatment is given to gear hobbing and gear grinding machines; tooth loading and distribution corrections; results of tests and experience with material combinations; single and double-helical gears; gearing configurations; types of epicyclic gears; applications to single and multiple diesel engines; reversing with steam turbines, diesel engines and gas turbines; reversing with epicyclic gearing; SSS clutches; MAAG synchronous clutch coupling; gear couplings; lubrication systems; adjustable bearing housings; journal, main wheel and thrust bearings; vibration; kinematics of tooth meshing; oil/material combinations; pitting and tooth breakage; gear damage; noise.]]></description>
      <pubDate>Wed, 08 Oct 1980 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/151657</guid>
    </item>
    <item>
      <title>GEAR LOADS DURING REVERSE DRIVE OR MARINE STEAM TURBINES</title>
      <link>https://trid.trb.org/View/80690</link>
      <description><![CDATA[The loads impose on mechanical gear transmission during the reversal maneuvers are examined because of unsteady loads and gear wear.  Large stress gradients in the gearing shafts and large, quickly alternating tooth forces and bearing forces are to be expected due to the decelerations and accelerations which occur for the rotational movements of the shafts, for instance, from an emergency or crash-stop maneuver.  Deviations from steady operating conditions may appear as to the hydrodynamic behavior in the friction bearings of the gear unit.  Alternating axial forces and torques emanate from the propeller and are forwarded over the shaft line to the gear.  Just so, alternating torques from the high-pressure and from the low-pressure turbine arrive at the gear, which depend on the time-variable course of the steam flow rates passing through the forward and the reverse valve.]]></description>
      <pubDate>Sat, 13 Jan 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/80690</guid>
    </item>
    <item>
      <title>DETERIORATION OF MARINE GEAR TEETH--CASES ENCOUNTERED AND SOLVED</title>
      <link>https://trid.trb.org/View/79348</link>
      <description><![CDATA[The rapid increase in the size of ships and their propulsion installations over the last three decades has caused a considerable rise in the incidence of damaged gear teeth due to the incompatibility of hull flexiblity and shafting stiffness.  Deformations of the hull structure due to loading conditions and sea state considerably exceed the allowable tolerances for marine reduction gear mountings. Cases of gear tooth damage encountered by the Author are illustrated.  Bureau Veritas investigations of pitting and tooth wear, etc. since they first began to show the effect of structural incompatibility and loading on damage, are presented and analysed, together with possible preventive measures.  Order from BSRA as No. 49,049.]]></description>
      <pubDate>Thu, 12 Oct 1978 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/79348</guid>
    </item>
    <item>
      <title>ACCURACY REQUIREMENTS FOR MARINE PROPULSION GEARS WITH SPECIAL REFERENCE TO AVAILABLE MEASURING EQUIPMENT</title>
      <link>https://trid.trb.org/View/68511</link>
      <description><![CDATA[This paper looks at the need for accuracy in marine propulsion gears in the light of the new ISO standards of 1976 which complement the British Standard BS 1807.  Errors linked to speed and to loading are discussed in detail.  The Author concludes that present marine gear accuracy standards bear no relation to the requirements of the gear itself.  It is to be hoped that the forthcoming revision of BS 1807 will go some way towards rectifying this.  Gear measuring equipment now available is adequate to cover requirements in respect of pitch and undulations.  Developments in respect of profile measurement of large gears, alignment measurement and surface texture recording in situ would be welcomed. Composite checking could also bear closer examination as a means of demonstrating profile accuracy on large gears. Order from: BSRA as No. 47,334.]]></description>
      <pubDate>Wed, 12 Apr 1978 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/68511</guid>
    </item>
    <item>
      <title>ANALYSIS OF STRESS DISTRIBUTION ALONG THE TOOTH CONTACT LINE OF LARGE MARINE REDUCTION GEARS AND MEASUREMENT OF STRESSES IN ACTUAL SHIPS</title>
      <link>https://trid.trb.org/View/60904</link>
      <description><![CDATA[In marine reduction gears of large width, "end tooth bearing" may occur because of shafting misalignment (due to installation error or hull deformation) and gear shaft deformation (torsional, bending, or thermal).  These factors interact with one another, making it difficult to take them into account for the quantitative determination of the distribution of tooth-root stresses.  The Authors present a new analytical method of calculating load distribution and root stresses, in which "end tooth bearing" is taken into consideration.  Results obtained with this method, in calculations for the bull wheel in a 400,000-dwt (45,000 hp at 85 rpm) tanker, are compared with the stress distribution along the contact line of the tooth root as measured with strain gauges.  Order from: BSRA as No. 46,936.]]></description>
      <pubDate>Tue, 07 Mar 1978 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/60904</guid>
    </item>
    <item>
      <title>HIGH PERFORMANCE EPICYCLIC GEARS FOR GAS TURBINES</title>
      <link>https://trid.trb.org/View/55763</link>
      <description><![CDATA[The history and explanation of hte Cinti-BHS load equalisation system for epicyclic gears is discussed in detail, Equations for relating gearbox size and weight are presented for parallel shaft and epicyclic gears.  A derivation for the maximum ratio for the number of planets is also included.]]></description>
      <pubDate>Wed, 23 Nov 1977 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/55763</guid>
    </item>
    <item>
      <title>SOME FACTORS IN MARINE GEARING FOR CLASSIFICATION PURPOSES</title>
      <link>https://trid.trb.org/View/47126</link>
      <description><![CDATA[The paper gives a brief history of the evolution of the Rules of Lloyd's Register of Shipping up to the adoption of the basic I.S.O. formulas for design, and analyzes the main defects in both steam turbine and oil engine gearing over the past seventeen years.  With this background, the values applicable to the factors for surface loading and tooth bending strength are discussed.  Finally, the manufacturing tolerances and installation practices, particularly with regard to external effects, necessary to obtain the conditions at the mesh appropriate to the permissible loadings, have been outlined.  I.S.O. notation has been used in the paper and, where the coefficients in Lloyd's Register's published Rules differ, the correlation has been indicated.]]></description>
      <pubDate>Tue, 26 Oct 1976 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/47126</guid>
    </item>
    <item>
      <title>CONTROL OF LOADING CAPACITY OF REDUCTION GEARS FOR MARINE APPLICATIONS</title>
      <link>https://trid.trb.org/View/10622</link>
      <description><![CDATA[The aim of this paper is to analyse the calculation criteria and procedures for checking reduction gear load capacity, i.e. the capacity of a gear mesh to transmit fully and safely a given torque, without causing failures such as "pitting" and "scuffing" or, even, breaking of the teeth, these being the most usual damages which gear teeth are likely to undergo.  To summarize, the above listed damages are due to an excessive tangential stress transmitted, i.e. to an excessive load on the teeth.  Since the tangential force or the load are functions of the maximum transmitted torque, it is necessary, to prevent such failures from occurring, to check down to a pre-determined value, for a given couple of gears, the value of such moment.  A theoretical analysis of the stresses actually taking place in reduction gears is quite difficult. It is a case, in fact, of a machinery component where a state of tridimensional stress with local concentrations effects, occurs because of a more or less pulsating load, leading back therefore to fatigue phenomena, and where a thorough surface finish, an accurate working, an effective teeth meshing, the pressure angle, the peripheral speed, the pinion deformation due to combined bending and torsion effects, the pre-tensions in the case of shrunk rims, etc. play a more or less important part affecting the results of experimental tests.  This phenomenon is even more complicated in marine applications, because of the hull deformations and of the particular securing arrangements which make alignments less accurate.  This explains why the criteria followed by various authors and by different manufacturers are often dissimilar and some times contradictory.  In view of the above, a checking of gear load capacity may be grounded on simplified calculation theories, adopting coefficients conveniently selected on the basis of experimental results.  Usually, such a checking is carried out taking into consideration the Hertz pressure and the bending stress.  It should be noted that, for non-surface-hardened gear teeth if the Hertz pressure checking criterion is satisfied; the one in respect of bending is generally also satisfied, the former being the most critical for non-hardened teeth.  Experience shows, in fact, these kind of teeth to be liable to pitting and scuffing damages rather more than to tooth breaking, unless flaws of the material exist, such as, for instance, the peculiar circumferential segregations.  As for hardened teeth (case-hardened or nitrided), which withstand high surface pressures, the bending strength becomes more relevant and a verification in this respect is therefore impervative.  The report sets forth the theory and ideas that dictate the present R.I.N.A. rules for checking gear load capacity against Hertz pressure and bending of teeth. They are quite in line with those followed by the ISO/TC60/GT6 Committee.]]></description>
      <pubDate>Thu, 24 Jan 1974 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/10622</guid>
    </item>
    <item>
      <title>INCREASE IN THE LOAD-CARRYING CAPACITY OF A LARGE-SIZED MARINE REDUCTION GEAR</title>
      <link>https://trid.trb.org/View/8840</link>
      <description><![CDATA[Deals with the development of high-hardness steel and accuracy of gear tooth finishing which are intended for increasing the surface durability of the marine reduction gear.  In conclusion, it is quite certain that the allowable K-factor of the newly developed gear material can be increased by approximately 60 percent as compared with that of the conventional material.  Also, it has been made evident that the surface roughness of the gear teeth has a great effect on the tooth surface durabilities.]]></description>
      <pubDate>Wed, 15 Aug 1973 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/8840</guid>
    </item>
    <item>
      <title>LET'S UP-DATE MARINE GEAR TOOTH BENDING STRESS CALCULATIONS</title>
      <link>https://trid.trb.org/View/8842</link>
      <description><![CDATA[Presents a method of applying the AGMA Fundamental Bending stress Formula to marine propulsion gear teeth.  It includes geometry factor curves for commonly used tooth forms, guidance on overload and load distribution factors, and suggested allowable design stress levels.]]></description>
      <pubDate>Wed, 15 Aug 1973 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/8842</guid>
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