“Slamming Load Effects on Ships and Marine Structures” By Professor Odd M. Faltinsen at Deep-Blue Forum

Professor Odd M. Faltinsen delivers a lecture entitled “Slamming Load Effects on Ships and Marine Structures” on 11 September 2023 at the Deep-blue Forum at Harbin Engineering University.

Slamming is of concern for structural design of ships, offshore platforms, lowering of subsea structures through the splash zone, accidentally dropped objects and launching of free-fall lifeboats from offshore platforms. Slamming on ships and sea structures causes both local and global structural response and ought to be coupled with structural mechanics to find important time scales of the many physical effects associated with slamming. Hydroelastic slamming has analogy to transient response of a mass-spring system. Important factors are the ratio between slamming duration and important structural natural periods, the time history of loading, added mass and slam damping. If the time scale of a fluid mechanic effect such as liquid compressibility or gas cavity oscillations is very small relative to the structural natural periods associated with maximum structural stress, the details of the fluid mechanic effect does not matter. Hydroelasticity of concrete shells, horizontal plates and wedge-shaped cross-sections during drop tests are theoretically discussed and partly compared with experiments. Both the water-entry and water-exit phase matter in describing the global load effect due to wetdeck slamming on catamarans and offshore platforms. Bow slamming and whipping of ships are discussed with emphasis on modelling of slamming in an engineering context. Sloshing-induced slamming in prismatic LNG tanks is perhaps the most complicated slamming problem because many fluid-mechanic and thermodynamic parameters as well as hydroelasticity may matter. Further, complicated in-flow scenarios of slamming may appear due to violent sloshing. The consequence is that both computational tools and model test scaling are limited.