Wave impact pressure and pressure impulse on a square column with an overhanging deck in regular waves

Abstract

As the main component of semi-submersible platforms, the deck-column structure is inevitably subjected to severe wave impacts in extreme ocean environments. The wave impact pressure and its time integral, impact pressure impulse, play an important role in the structural design, especially for the analysis of dynamic response. To investigate the characteristics of impact pressure and pressure impulse, wave impact tests on a square column with overhanging deck were carried out under a series of regular waves. Wavelet denoising technique and empirical mode decomposition (EMD) method were employed to remove the noise interference and the dynamic amplification effect from raw data. Considering the stochastic feature, statistical analysis of pressure impulse was performed based on generalized extreme value (GEV) and two-parameter Weibull distribution models. The results show the strong variability of the wave pressure impulse and the necessity of statistical analysis even in regular waves. The peak impact pressure is more sensitive to the variation of initial air gap and column incline angle than the pressure impulse. The probability distribution of extreme pressure impulse agrees well with the GEV distribution and is mainly distinguished by the shape parameter. Furthermore, the probability distribution of extreme pressure impulse is significantly affected by the initial air gap, and the effect is also related to wave parameters. The present research reveals the probability distribution of wave pressure impulse in regular waves and lays a foundation for the statistical analysis of pressure impulse in irregular waves.