STRUCTURAL RESPONSE TO EXPONENTIALLY VARYING HARMONIC EXCITATIONS.

Modal analysis predicts the response of a structural system by means of the natural modes. If the distribution of the applied force does not conform to the first few natural modes, the response is rather difficult to determine due to the fact that higher modes are relatively more expensive to compute and are also subject to computational errors. However, in a harmonic oscillation, the forcing vector and the response vector are closely related by the dynamic stiffness matrix, and the response amplitude can be obtained simply by solving the set of linear equations with complex coefficients or each excitation frequency and dynamic stiffness matrix. The purpose of this paper is to point out that the method, applicable to harmonic oscillation, can be extended to exponentially varying harmonic excitation of other forms.