8.2 Dynamic characteristics Ë 263SWJTU, China, will be systemically summarized and reviewed in the next sections to
illustrate the continuous R&D on HTS Maglev vehicles in the field for rail transit.
8.2 Dynamic characteristics
8.2.1Vibration performance
As a significant experimental dynamic testing method, the vibration test is performed
to determine the physical nature, vibration parameters and possible motion modes of
a HTS Maglev vehicle system as the preliminary to the experimental design. A scaled
HTS Maglev vehicle model (see Fig. 8.1) with 4:1 ratio to the first manned HTS Maglev
test vehicle [5] was made and measured with different field cooling heights (FCHs)
and working heights (WHs). In this model, the on-board liquid nitrogen vessels on
each side of the vehicle model were those employed in the first manned HTS Maglev
test vehicle [5] which guarantees that the vibration parameters were the same value
for both.
The vehicle model was 0.8 m in length, 1.2 m in width, and 0.35 m in height. The
total weight of the model (including the vessels with liquid nitrogen) was 32 kg. There
were 43 cylindrical melt-textured YBCO HTS bulks in each vessel. Each YBCO bulk was
of 30 mm in diameter and 17 mm in height.
An 11-ch vibration measurement (3560C, Bruel & Kjear S&V) was applied together
with six piezoelectric accelerometers (4507B-004, Bruel & Kjear S&V). Cartesian coor-
dinate was set-up to analyze the equivalent dynamic model of the HTS Maglev vehicle.
Seven accelerometers were used to sample the vibration signals at seven keypoints
on the upper surface of the model, represented by A, B, C, D, E, and F, respectively,
in Fig. 8.2. They were divided into two groups A–C and E–F, which were fixed on each
side of the vehicle model levitated over the PMG. All vibration signals were analyzed
Fig. 8.1:Photo of the vibration experimental set-up. Points A, B, C, D, E, and F stand for the
accelerometers.