A method for vibration-based health monitoring using nonlinearity measurement

Abstract

This paper proposes a practical method for input-output vibration-based health monitoring. The method using degree of nonlinearity (DON), which overcomes the limitation of linear models, is proposed. Derived from the Hilbert transform of the frequency response function, the DON can measure how much the nonlinearity is present in the vibration response. The results in this paper show that the DON of a structure has a specific relationship with the magnitude of the excitation. When computed from the structure that is still healthy, this relationship can be used as a baseline for the health monitoring. If the structure is not healthy, the new computed DON will deviate from this baseline.