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Test your gear stress analysis skills and learn about the changes to ISO 6336 by joining ISO 6336 SIG– free of change to BGA members.

2019 was marked, for some at least, by the long-awaited revision of ISO 6336 stress analysis standards part 1,2 3, & 6.  It involved some very important changes including

  • the helix angle factor Yβ to fix errors with evaluating higher helix angle gears,

  • improvements in accounting for variation in applied load and miners sum cumulative damage

  • and numerous other corrections and adjustments that were identified when example calculations were prepared for ISO 6336-30: 2017. 

Overnight, with the revision of ISO 6336, gears that were previously showing stress safety factors that were acceptable may, with the new procedures be unacceptable.  Conversely some gear geometries and load conditions may result in predicting higher safety factors.  This requires detailed knowledge of the changes and how they impact the revised value to enable sensible decisions are made.  The BGA SIG may be able to help you here.

The SIG decided that that first project would be to run a confidential round robin comparison exercise.  The initial work looked at a few simple examples but his has been expanded to

  1. test all the ISO example in ISO 6336-30:2017 using the older version of the standard

  2. recalculate and test results with the new version of the standard to assure

    1. the changes have been implemented properly in the software you use

    2. we can identify where the changes have been made and the type of gears and load conditions that are affected.

    3. Difference between software users are quantified.

SIG participants share their analysis results confidentially and the process is managed by the BGA and Design Unit at Newcastle University.  We can identify differences between software packages and different users.  It is an ideal way of testing your analysis skills, gear stress analysis knowledge and learn more about the ISO standard.

If you are interested in learning more about ISO 6336- how it works, its strengths and weaknesses, then please contact the BGA and you would be very welcome to participate with this SIG round robin. 

Membership of the SIG is free to BGA members.

Please contact Kirsty at the BGA if you wish to participate.  We look forward to hearing from you.


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