1986 Volume 52 Issue 483 Pages 2808-2813
The equation of motion whose general restoring terms are modified from these derived in the previous paper is analyzed to show the physical explanation of the instability phenomena of the previous system. This analysis shows that the instability characteristics are decided by the symmetry of the non-diagonal elements of the restoring term. Based on this result, the instability analysis of the previous system is performed more exactly than in the previous paper. As a result of the analysis, the following new points are found : the difference of the instability tendency between models M-4 and S-4 is caused by the instability type i.e. statical or dynamical instability ; Statical instability as well as dynamical instability can occur in model M-4 ; Statical instability can occur also in model S-2.