Abstract: This paper consists of two parts. One is on fluid-structure coupled vibra-tional analysis of hydraulic pipeline. The other deals with piping reliability analysis.First, a finite element analysis of the frequency characteristic of a slender fluid-structure system, namely the elasto-acoustic beam is presented. An original symmetric formulation is derived with one new field in the fluid, namely the "mass-flow", and a displacement field in the structure. The frequency characteristic of a part of hydraulic pipeline system in a certain aircraft is. analysed. Second, a piping reliability analysis for the hydraulic pipieline is presented. The analysis is based on probabilistic fracture mechanics model, and leak is defined as the only failure criterion. The influence of cyclic vibratory stresses is taken into account. The probability of the piping failure at different numbers of cycles and cyclic stresses is given as a result of numerical simulation by using Monte Carlo technique.

Key words: fluid-structure interaction, hydraulic pipeiline, piping reliability, probabilistic fracture mechanics