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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>
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      <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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      <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>
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      <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>
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    <item>
      <title>GEARING FOR MODERN MARINE PROPULSION SYSTEMS</title>
      <link>https://trid.trb.org/View/40352</link>
      <description><![CDATA[The purpose of gearing in marine propulsions is to enable both engine and propeller to function to their best advantage.  The application of gearing to steam turbines gas turbines, diesel engines, electric drives and combined power units is considered, along with modern ideas regarding materials, tooth form, gear arrangement, gearcase structure and ancillary equipment.  Traditional limitations on the use of nitrided steels are analyzed, and the value of the popular Hertzian shear stress criterion is challenged.  The future place of epicyclic gears is discussed with particular reference to diesel drives.  The effect of friction forces in tooth-coupling drives is dealt with.]]></description>
      <pubDate>Tue, 30 Sep 1975 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/40352</guid>
    </item>
    <item>
      <title>HYDROFOIL STRUT ARRAY HYDRODYNAMICS</title>
      <link>https://trid.trb.org/View/24660</link>
      <description><![CDATA[The hydrodynamic problem of calculating the potential flow characteristics of a hydrofoil atteched to a strut is discussed.  A computerized-numerical method based on linear lifting surface theory is used to calculate the lift, induced drag and pressure distribution of an unswept, untapered, planar hydrofoil attached to a symmetrical strut with or without an axisymmetric nacelle in the mid-wing position at the junction of the foil and strut.  Particular attention is given to the junction of the foil with the strut or nacelle.  One of the several practical results of the program is the ability to calculate the cavitation inception speed of the complete hydrofoil system.]]></description>
      <pubDate>Thu, 16 Jan 1975 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/24660</guid>
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    <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>
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    <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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