Experimental research on the vibration of aviation elbow tube by 21~35 MPa fluid pressure pulsation

The experimental study investigates the vibration responses of aviation elbow tubes under various pressure pulsations, with a focus on different tube layouts. Three sets of tube specimens were designed, each varying in bending position, radius, and angle. Pressure pulsation excitations, characterized by different working pressure levels, amplitudes, and frequencies, were applied to these specimens. The layout parameters were found to affect the stiffness of the tubes both on the Elbow-tube Plane and the Normal Plane. It was observed that the resonance acceleration amplitude is approximately 4 to 8 times greater than that in the non-resonant state, while the resonance stress is about 6 to 14 times higher than in the non-resonant state. Additionally, stress increases by 30% to 70% when the working pressure level in the tube rises from 21 MPa to 35 MPa. An increase in the amplitude of pulsation excitation from 5% to 10% results in acceleration and strain response amplitudes escalating from 55% to 2 times. Notably, when the bending position is centered and the radius is fourtimes the tube's outer diameter, the elbow tube exhibits the largest acceleration and strain responses. Positioning the bending point close to the constrained end and employing alarger bending angle can effectively reduce tube vibration. This research provides valuable insights into the dynamic design of high-pressure aircraft pipeline structures.