ACOUSTIC-STRUCTURAL COUPLING IN PIPEWORK

摘要

If an acoustic resonance is set up in a pipework system then it may cause structural vibration which can lead to a catastrophic fatigue failure. An investigation is made into the coupling between acoustic waves and pipework stress with the objective of developing a simple method for determining if stresses are excessive. The analysis of the coupled acoustic and structural vibration results in a two-degree-of-freedom model with two natural frequencies and two damping ratios. This model is impractical as an assessment tool because the natural frequencies and damping ratios are either not known at all or are only known imperfectly. The model is therefore manipulated to give the stress corresponding to the most unfavourable conditions for the natural frequencies. This results in a useful assessment equation which may be used in practical circumstances. Comparisons are made with an alternative assessment method based on uncoupled behaviour.