Structural damping determination by finite element approach

摘要

An iterative numerical method is described by which the non-linear material damping of a structural member can be evaluated in a simple way. It is shown that the results of a conventional finite element approach can be combined with the damping-stress function, which is assumed to be known from experimental data, to obtain the loss factor of a particular structure. For this reason the dynamic stiffness concept is utilized in which the imaginary part of the modulus of elasticity is function of stress range. Since stress amplitude depends also on the amount of damping present in structure, a numerically iterative scheme is developed for the computaiton of the non-linear structural damping. Independently of the type of intercoupling between stress distribution function and damping-stress function, suitable solutions may be obtained to yield the loss factor of a particular member. This fast converging approach is accurate, stable and may be generalized to evaluate the loss factor for any structure.