AUTOMATIC CHOICE OF GLOBAL SHAPE FUNCTIONS IN STRUCTURAL-ANALYSIS

Linear analysis of highly complex structures is now feasible with standard finite-element programs. Nonlinear static or dynamic analysis of the same strwctares, however, often makes impossible demands on computer resources. A method is presented in which the nonlinear portions of the analysis are carried out in a reduced equation system, in which the generalized degrees of freedom are the coefficients in a summation of global shape functions. These functions are selected from the space of trial functions defined by a finite-element discretization, important features of the method are: 1) rigorous treatment of the geometric nonlinear effects (complete coupling of global shape functions); 2) automatic problem-dependent choice of giohal shape functions; and 3) continuous monitoring of solution accuracy. The procedures are demonstrated by application ir3 analysis of beams and arches. © 1978 American Institute of Aeronautics and Astronautics, Inc., All rights reserved.