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Inclinometry and strain gauge measures done simultaneously
SUMMARY
Data were taken on both 990320 and 990321. As with inclinometry alone, the data are taken at a general azimuthal resolution of 1 degree, increasing to 0.2 degrees at the azimuths where the wheels were expected to move over the strain gauge. The 990320 dataset revealed the need for some adjustments to these azimuths. This was done, and the strain gauge data of 990321 are shown below. The first plot is the entire sweep of data, and the four subsequent plots show details of the 4 wheels passing over the gauge :
The azimuths of the wheel/strain-gauge events are (7.8), 104.6, 187.8, 284.6, and 367.8 (+- 0.1), with profile FWHMs of about 0.9 degrees. My previous, erroneous estimate of these locations may have compromised Justin's analysis of wheel loadings . The profiles are similar in each case, and show the structures reported previously by Ian Pain. The 0.2 degree resolution is insufficient to reveal the small scale ripple noted in Ian's analog experiments. The only extra oddity is the feature at azimuth 270, in the approach of wheel #2 to the gauge. This is approximately where wheel #2 leaves track segment #5 (going CW to segment #6 - see the table of wheel-joint interactions). The data show the strain gauge deflections to be in the ratio 110 : 200 : 270 : 100 for wheels 1, 2, 3, 4, which is not so 'back-heavy' as the 1 : 3 : 4.5 : 1 measured in October 1998 . The last central bearing load adjustment left 91% of the antenna load on the central bearing. If the antenna weighs 100 tons (alternately 130t), the wheel loadings are 1.5t : 2.6t : 3.6t : 1.3t (or 1.9t : 3.4t : 4.6t : 1.7t) - with wheel #3 (back left) in excess of the specified 3.5t maximum load.
Iain Coulson 23 Mar 1999 - updated for new web structures 02 July 2000 |
