Optimization of the dynamic stiffness of the seismic vibrator

Abstract

Due to the sweep excitation of the vibrator, the dynamic stiffness of the seismic vibrator has an enormous influence on the performance of the vibroseis system and the accuracy of the output signal. In order to improve the dynamic stiffness of the vibrator, an optimization strategy is presented to improve the weak link which is defined by dynamic analysis of the vibrator. The weak link is the weakest part, which brings about the resonance, and the weak link in different excitation frequencies is identified by dynamic stiffness analysis in this method. A modified finite element model with reaction mass is built; harmonic response analysis and modal analysis are employed to find out the weak link of the vibrator, which indicates that the supporting column is the weakest component. Sensitivity analysis is used to determine the optimization parameters of the supporting column. Response surface model developed from a parametric finite element model is used to establish the objective function, and the mass is the constraint condition. The optimization problem is solved by particle swarm optimization, and the dynamic stiffness of the optimized vibrator is calculated by harmonic response model. Results show that compared with the original model, the natural frequency of the optimized vibrator is increased by 6.63% and the resonance peak is decreased by 9.00%.