The Research of Structural Modal Parameter Identification for Oil Derrick

The oil derrick structure which is the main force bearing component in oil production, to take safety assessment on it has important realistic significance. Through random reduction method to get free vibration response of the derrick structure under ambient vibration, and using the ITD method to carry out modal parameter identification on multi-points impulse response data. numerical simulation analysis shows that the identified modal frequency and modal shape and the finite element analysis results are basic coincidence, and modal damping ratio identification results, there exist the false damping ratio, need artificial identification. So for the large structures which is difficult to apply direct incentive, RD & ITD method is feasible, and suitable. This method provide theory basis for oil derrick structure to the safety assessment work, and reduce the hidden engineering accident effectually.