SEMIDEFINITE VIBRATION ANALYSIS OF ELASTIC STRUCTURES MOUNTED ON NONLINEAR SUPPORTS

摘要

The dynamic motion of elastic structures may be solved either in space of positive definite, or alternatively, in space of semidefinite eigenvectors. The former way requires for fixed vector basis the supports to be constant and to behave linearly whereas the latter method works also with varying configurations of nonlinearly behaving attachments, which may be either passive vibration isolators or actively controlled actuators. As a case study the finite element description of a vibrating frame structure mounted on elastic isolators has been constructed. Based on the proposed concept the dynamic equations of motion have been written in terms of semidefinite eigenmodes. Frequency responses have been solved showing excellent correspondence to the reference solution obtained from computationally much more demanding full nodal d.o.f. description.