Abstract
This paper describes identification of spatial modes in a chaotic vibration involving dynamic snap-through for a buckled beam witha concntrated mass. The beam is constrained by an axial elastic support and both ends of the beam are fixed. Using KL(Karhunen-Loeve) method, time histories are decomposed into components which have no corelation each other. Eigenvalues of covarriance matrix of the time histories correspond to contribution of the components to the original time history. The eigenvectors correspond to spatial modes(KL modes) in the chaos.The identified KL modes from numerical analysis were compared with the KL modes from experiment whichi was carried by the authors. Calculated results were consistent with experimental results in number of principal KL modes, shapes of KL modes, dimension,time histories,Fourier spectrum,linear natural frequencies and static restoring force.