WAVE PROPAGATION IN PIPES WITH HELICAL PATTERNS

Pipe installations are widely used in many industrial applications, particularly in oil, water, natural gas distribution and chemical industry. Although there are many different constructions according to the specific application, these pipes often consists of synthetic rubber which covers reinforced wires wound along helical lines around an inner synthetic rubber tube. Theoretical understanding of wave propagation in these pipes, and in particular dispersion curves and wave–modes, provides information about the dynamic behaviour and stress state of the structure, and it is essential in many applications such as transmission of structure–borne sound, statistical energy analysis, shock response, non-destructive-testing and structural-health-monitoring. In this paper wave characteristics in pipes with helical pat-terns are studied. In particular wave propagation in cylindrical structural with helical orthotropic characteristics are investigated and some interesting characteristics of wave propagating in these structure are showed and discussed. Two different approaches, the Wave Finite Element method and an analytical model of a thin helically orthotropic cylindrical shell, are used and results are compared. Both methods are very efficient in terms of computational cost, theoretical understanding of the wave characteristics and utilisation of the model for optimisation procedures, where the model is reconfigured for each new set of parameters.