Impedance analysis and clamp locations optimization of hydraulic pipeline system in aircraft

The excessive vibration of hydraulic pipelines in aircraft is an important safety issue. The traditional vibration control method paid more focus on the pipe vibration which is the end of vibration energy flow not the vibration origin. Pressure fluctuation of the hydraulic oil causes the pipes vibration directly. The system impedance is a key factor to the hydraulic pressure fluctuation under the definite flow rate. Our objective is to minimize the system impedance at the frequencies of the vibration source. For accurate impedance calculation, the clamps are considered as cantilever beams not fixed points. The system impedance in frequency domain was obtained by using Transfer Matrix Method (TMM). The frequency of vibration source in hydraulic system is determined from the rotational speed of pump. The objective function is defined as weighted sum of system impedance at frequencies of vibration source. Variation of the clamp locations was adopted to change the system impedance. The Chaotic Swarm Particle Optimization (CPSO) algorithm was applied to determine optimal clamp locations, and the value of objective function using CPSO decreased by 77.67% compared to the original system, meantime, the optimal clamp locations were obtained.