DYNAMIC ANALYSIS OF LARGE STRUCTURAL SYSTEMS WITH LOCAL NONLINEARITIES

In many types of structures that exhibit significant nonlinearity during dynamic response the nonlinear stiffness property is confined to a few predetermined localities. This physical characteristic may be exploited by making use of substructure concepts in the dynamic response analysis. The elastic components may be represented by a small matrix of stiffness coefficients coupling them to the nonlinear elements, and only the properties of the few nonlinear elements need be modified during the response analysis. Both direct and indirect techniques for taking advantage of localized nonlinearity are reviewed here. In the direct methods the equations of motion are integrated by step-by-step procedures. Various methods of reducing the effective number of degrees of freedom are discussed. In the indirect methods the response to simple loadings is determined, and the response to the prescribed loading is obtained by superposition. A technique for applying superposition to the linear portion of the structure while treating the nonlinear region by a step-by-step procedure is described. © 1979.