2. Basic Technology Development
In fiscal 2001, research and development was focused on clarification of superconducting magnet vibration and analysis of aerodynamic characteristics in tunnels.
(1) Measures against Vertical Bending Vibration of a Superconducting Magnets at High Speed
One possible measure to reduce the costs of Superconducting Magnetically Levitated Transportation System is to reduce the number of ground coils.
Reducing the current number of levitation coils by half leads to the problem of vertical flexural resonance modes arising in the superconducting magnets currently in use, resulting in an increased heat load. It has been verified that, among these resonance modes, the primary flexural resonance mode is strongly affected by outer vessel rigidity, while the secondary flexural resonance mode is strongly affected by rigidity of the vertical load support material.
As a measure against the vertical secondary flexural resonance mode at high speed contributing substantially to increase of heat load, performance tests were carried out this fiscal year on vibration characteristics and heat penetration amounts. These tests used a mechanical vibration-testing device in which vertical load-supporting material with enhanced rigidity was attached to the superconducting magnet for testing (Fig. 9).
The prospect was thus opened up of raising resonance frequencies above a running speed range with no substantial effect on the steady-state amount of heat penetration.