Responses of pipe system with flexible clamp under harmonic excitation

For analysis of vibration of aeroengine pipe system with flexible clamp, the stiffness characteristics of a flexible clamp and the effect of the flexible clamp on the pipe system response were studied, respectively. Considering the fluidstructure interaction, a dynamic model with pipe and flexible clamp was proposed based on the finite element model. The Newmark numerical integration was then utilized to obtain the timedomain responses. The stiffness of the flexible clamp was derived analytically and verified by the test. The result showed that the stiffness of the flexible clamp was piecewise linear stiffness. Responses of a pipe system with flexible clamp under harmonic base excitation were simulated, and the effects of the flexible clamp stiffness on the nonlinear dynamic behavior of the system were also discussed in detail. The results show that the amplitudefrequency curves of the responses become obviously nonlinear with the increase of the flexible clamp stiffness asymmetry. Within certain excitation frequency ranges, both subharmonic and multiharmonic responses could be found in the system responses. The natural frequencies decreases with the increase of flow velocity and pressure.