Resumo

OMER, H  e  BEKKER, A. Detection of Wave Slamming Sites from Ship Deflections. R&D j. (Matieland, Online) [online]. 2016, vol.32, pp.50-57. ISSN 2309-8988.

Stern slamming wasfound to be particularly problematic on a South African Polar Supply and Research Vessel. It inhibits oceanographic research operations and causes violent wave activity on the aft-deck where container laboratories are mounted. A methodology is required to distinguish between bow- and stern slamming in order to study full-scale ship responses. It is hypothesized that the wave slamming impact site can be verified from the animation of acceleration time histories ofpurposely placed accelerometers throughout the vessel structure. Vertical vibration measurements were performed atfifteen locations on the ship to capture a global sense of the slamming responses. Operational deflection shapes were calculated from these signals to infer if bow- and stern slamming can be distinguished. Results reveal that slamming vibrations propagate throughout the structure, causing a transient oscillation, known as whipping. The visualization provided by operational deflection shape analysis confirms that the wave impact site can be identified such that bow- and stern slamming events can be distinguished. A future investigation is recommended to determine if slamming may lead to structural fatigue of the vessel.

Palavras-chave : Operational deflection shapes; wave slamming; whipping; ship vibration.