MEASUREMENT OF THE LONGITUDINAL TRANSMISSION CHARACTERISTICS OF FLUID-FILLED HOSES

Flexible hoses used within a hydraulic circuit can reduce the levels o f both pressure fluctuations and structural vibration. An important ap plication is in automotive power steering where tubular inserts and re strictors are often used inside a hose to enhance the reduction of pre ssure ripple. The performance of a hose assembly in the frequency doma in is usually specified by an impedance matrix relating pressure and f low ripple at the ends. However, these quantities are coupled to fluct uating axial tension and motion of the hose walls and it is desirable to have a 4 X 4 impedance matrix relating the complex amplitudes of al l these quantities. A convenient method of experimentally measuring th is matrix is presented. As well as allowing investigation of the main structural and fluid transmission from the hose assembly to the subseq uent pipework, the 4 X 4 impedance matrix provides a way of obtaining the dynamic properties of hose walls under realistic conditions for us e in further studies.