Numerical evaluation of an identification technique for flexibly supported rigid turbomachinery foundations

摘要

Appropriate modelling of turbomachinery foundations of existing installations is essential for determining the vibration behaviour of the machine. Earlier work had shown that provided one has an accurate rotor model and provided the system response is periodic, a practically feasible approach for identifying the relevant foundation parameters was possible in just two rundowns (one rundown only if the unbalance distribution is known) when the foundation consisted of simple pedestals. This paper generalises the approach to identifying all rigid body modes of a flexibly supported rigid foundation, allowing for the possibility of coupling or cross talk between the bearing supports. Numerical experiments show that the proposed approach is theoretically sound and practically realisable, in that identification is possible with 2 digit measurement accuracy, and potential problems of bearing force evaluations are circumvented.