On 8^th May 2002, the Minden meeting of ISO 108/SC2/WG7 was held in 09:00-17:00 at Bently Nevada Corporation, Minden. Nevada, USA

　

(1) The opening and greeting of members was made. We have the following attendees:

　

　

(2) The prepared agenda of N187 was introduced and adapted.

(3) The distributed documents were introduced.

(4) We reviewed the status of our standard ISO 14839 series being developed by WG7 and ISO rules

　

　

(5) We reviewed previous documents and minutes with respect to stability margin

　

　

(6) We discussed the revision of WD 14839-3

(7) Approach/design for documentation on stability margin is discussed:

　

Minutes of ISO TC108/SC2/WG7 Minden Meeting, 2002-05-08

　

On the 8th May 2002, the Minden meeting of ISO 108/CS2/WG7 was held from 8:00 until 17:00 at the offices of Bentley Nevada Corporation, Nevada, USA.

　

(7.1) There was a lengthy discussion of the API stability paragraphs and the fact that similar standards are already provided in ISO 10814. Thus, it was agreed that our additions should focus on stability issues introduced by modes at frequencies significantly higher than the nominal operating speed range.

　

(7.2) Once this discussion was concluded, we discussed the issue of whether the stability standard should dictate experimental evaluation or computational evaluation. It was agreed that the primary function of the standard should be to assure potential users that there is a clear test that can provide them a reasonable guarantee that an accepted machine will not be overly sensitive to variations in operating conditions. It was further agreed that computational assessment can't provide this kind of assurance and that an experimental standard is more appropriate.

　

(7.3) Having accepted the need for an experimental standard, the committee then addressed what measure should be used. There was a lengthy discussion of the relative merits of four different tests:

At the end of this discussion, it was agreed that test (d) is the most reliable and is acceptably easy to measure. Therefore, the standard will focus on test (d): either Nyquist minimum distance or peak of the sensitivity function.

　

(7.4) We then discussed the impact of the new API stability paragraphs (which specifically dictate the use of "synchronously reduced tilt pad bearing coefficients") on magnetic bearing system stability prediction. It was agreed that the ISO stability document should address this point in the simplest possible manner. Consequently, a paragraph (or several paragraphs) will be drafted for inclusion in this standard which stipulates use of the full controller transfer functions in stability prediction, rather than some corollary synchronously reduced equivalent stiffness and damping.

　

(7.5) A sequence of revision of the stability standard was discussed. Prof. Matsushita will first revise the existing draft to focus only on Nyquist/Sensitivity measurement He will then ship the document to Prof. Maslen, who will add his comments and insert the discussion of computational assessment of stability. Prof. Maslen will then return the annotated document to Prof. Matsushita for draft revision. It is anticipated that this work will be completed by the middle of June. Prof. Matsushita will then distribute the heavily revised stability document to the committee members and other interested parties.

　

(8) We then had a brief discussion of part 4: Technical Guidelines. Prof. Matsushita informed us that he has received a lengthy and very useful discussion of auxiliary bearing drop testing from Prof. Kirk. He also informed the committee that the Japanese team is in the process of drafting language for an actuator sizing standard. These elements will form a substantial portion of part 4.

　

(9) No other items is discussed.

　

(10) Information of Upcoming Meeting Schedules

(11) Closure of Meeting

The convenor expressed his thanks to all of the attendees and Dr. Don Bently of BNC, for his cooperation of the ISO TC 108/SC2 conference..

　

　

Prediction of Groundborne Vibration arising from Rail Systems in Tunnels (1HZ - 500Hz) 8^th May 2002

　

　

1. The Working Group had agreed on future parts that would be developed:

　

　

The WG would prepare scopes and seek approval from ISO/TC108/SC2 for the future Parts, and will concentrate on developing those in order of increasing priority from parts 2 to 5. No resolutions were taken in this respect until the WG had itself developed and approved the scopes.

　

　

　

　

Resolution 1:

　

An edited version of ISO/CD/14837 -1 (doc ISO/TC108/SC2/WG8 N81) that addressed comments during WG8 meeting on 7/8^th May 2002 would be circulated to all members of WG8, with a view to approving its issue as a DIS, during August 2002.

　

Resolution 2:

　

A new work item proposal would be prepared to address "Rail track geometry", that would make some use of ISO/DIS 9629, during August 2002.

　

Convenor Dr. Ather K sharif