NUMERICAL ANALYSIS OF BIFURCATION BUCKLING FOR ROTATIONALLY PERIODIC STRUCTURES UNDER ROTATIONALLY PERIODIC LOADS

By considering the characteristics of deformation of rotationally pe-riodic structures under rotationally periodic loads,the periodic structure is dividedinto some identical substructures in this study.The degrees-of-freedom(DOFs)ofjoint nodes between the neighboring substructures are classified as master and slaveones.The stress and strain conditions of the whole structure are obtained by solvingthe elastic static equations for only one substructure by introducing the displace-ment constraints between master and slave DOFs.The complex constraint methodis used to get the bifurcation buckling load and mode for the whole rotationally pe-riodic structure by solving the eigenvalue problem for only one substructure withoutintroducing any additional approximation.The finite element(FE)formulation ofshell element of relative degrees of freedom(SERDF)in the buckling analysis is de-rived.Different measures of tackling internal degrees of freedom for different kindsof buckling problems and different stages of numerical analysis are presented.Somenumerical examples are given to illustrate the high efficiency and validity of thismethod.