Natural frequency sensitivity and influence analysis of tbm cutterhead system

Abstract

TBM cutterhead works in complex working conditions, which endures the reverse impact forces of rock breakage, resulting in parts abnormal failure. Hence, the study of the system inherent characteristics is the basis for cutterhead dynamic design. Based on the established vibration model of a TBM split-cutterhead system, the modal method is used in the dynamic model and the natural frequency sensitivity expressions to system parameters are deduced. Then a cutterhead system of a water conservancy project in China is taking as an example, the natural frequency sensitivity with respect to the cutterhead support stiffness and mass parameters is obtained, and the influence of the two parameters on natural characteristics is analyzed. The results show that, the 10th-20th order natural frequencies are mainly affected by the cutterhead support stiffness and mass parameters, and the 9th-11th order frequencies are mainly influenced by cutterhead moment of inertia. Besides, with the change of stiffness and mass parameters, the cutterhead system natural frequency curves cut across each other and there are also many inflection points in the sensitivity curves, then the modal jumping occurs near these points. The parameter sensitive points were obtained from the results, which can provide reference for TBM cutterhead system parameters matching.