Real-time assignment method of resonance frequency by change of coupling stiffness for improving road induced noise

This paper proposes a method for natural frequency assignment by semi-actively changing coupling stiffness matrix. This method can decide the coupling stiffness basically in one-time calculation to assign natural frequency. For two vibration systems connected with springs at multi-points, the compliance matrix which is sum of two system's compliance matrixes and the inverse matrix of coupling stiffness matrix at coupling degrees of freedom becomes rank deficient at natural frequencies, and consequently the condition for resonance occurrence is equivalent that all column vectors of the matrix exist in a hyperplane. The coupling stiffness is obtained to meet this condition by inner product calculation between a column vector in the compliance matrix and the normal vector of a hyperplane at required frequency. In a feasibility study, the method was applied to two beams connected with three translational springs.