In this paper, a method for the introduction of the effect of vibration frequency on dynamic contact stiffness of joints is presented. The 'method is based on the measurement of the natural modes of vibration of a simple mechanical system containing the joint to be investigated. The res-,ults of measurement are used, through a sensitivity technique, for the id-entification of a joint stiffness matrix. This matrix is assumed, at firs, to be invariant, i.e, independent on the mode of vibration. However, the utilization of the identified eigensolution and the equations of sensitivity .corresponding to a single mode of vibration, enable one to obtain, for this: mode, a correction joint stiffness matrix.
The validity of the method has been tested by numerical simulation on a case of a plane prestressed joint between two beams.