Vibration analysis of open TBM gripping-thrusting-regripping mechanism

Abstract The gripping-thrusting-regripping mechanism in the open tunnel boring machine is inevitably excited by strong impacts during tunnelling operations, leading to severe vibrations and unexpected wear in the joints and/or damage to the other machine components. Therefore, it is crucial to gain deep insight into the dynamic behaviours of equipment in tunnelling operations. This paper presents an approach for the elasto-dynamic modelling of the mechanism, by considering the surrounding rocky boundary conditions and configuration-dependent rigidities of the actuators, joints and key components, allowing for the dynamic response and vibration energy distribution to be predicted theoretically. The agreement between the analytical model and finite element model at frequencies and mode shapes proves the effectiveness of the modelling method. The simulation results demonstrate that the first four mode shapes dominate the dynamic system behaviours as a whole during tunnelling operations. The outcomes are helpful in predicting the dynamic behaviours of the mechanism so that weak links can be identified and subsequently improved during the design stage.