6Gastebled O J, May I M. Bifurcation in the numerical simulation of softening mechanisms [ J ]. Computers and Structures, 2000, 78(6) : 745-755.
7Almroth B O, Felippa C A. Structural stability [ A ]. Pilkey W, Saczalski K, Schaeffer H. In:Structural Analysis Computer Programs : Surveys, Assessments and Availability [ C ].Charlottesville : University Press of Virginia, 1974.
8Thompson J M T, Hunt G W. Static and Dynamic Instability Phenomena [M]. London: Wiley, 1983.
9Crisfield M A. Nonlinear Finite Element Analysis of Solids and Structures, Vol. 1 [M]. UK: Wiley, 1991.
10Crisfield M A. Nonlinear Finite Element Analysis of Solids and Structures. Advanced Topics, Vol. 2 [ M ]. UK : Wiley,1997.