AN EFFICIENT METHOD FOR FORCED NONLINEAR RESPONSE USING A STRUCTURAL DYNAMIC MODIFICATION TECHNIQUE

摘要

Generally, for nonlinear response analysis involving discrete nonlinear elements such as typical mounting connections, the physical finite element mass, damping and stiffness matrices are used in a direct integration algorithm to form the nonlinear response solution. Due to the large size of these matrices, forced nonlinear response analysis requires significant computational resources, Using a mode superposition technique, the response of the structure can be characterized at particular time intervals by the linear superposition of the modes of the system. As different discrete nonlinear elements are activated in the system, the modal character of the structure is updated using a structural dynamic modification process. Using the modification process, the modal character of the structure can be updated very efficiently and then, the response using mode superposition techniques can be estimated very efficiently even though nonlinearities exist. This technique, referred to as the Modal Modification Response Technique, is illustrated using simple structures that contain discrete nonlinear connection/gap elements and is compared to traditional direct integration techniques. Advantages and limitations of this technique are discussed.