THEORETICAL RESEARCH AND EXPERIMENTS IN SLAMMING

RICERCHE TEORICHE E SPERIMENTAL NELLO SLAMMING

The parameters which have effect upon ship-slamming are investigated, i.e. periods of natural pitching and heaving, speed, draft, wave length and depth. The formula giving the probability of occurrence of slamming as a function of relative motion and relative velocity between wave and ship bow and of the square of the draft at the ship bow is discussed. The applicability of the Superposition Technique for prediction of slamming is also explained. The results are given of some theoretical researches in which the mechanism of the occurrence of the slamming impulse can be explained: wedge-shaped body impact theory, Wagner theory, Von Karman and Wattendorf theory based on the fluid compressibility and finally Sheng-Lu Chuang theory based on the compressibility of both fluid and air, trapped between the falling body and the fluid. In the second part, the results are given of experimental researches with models investigating the magnitude of slamming impact pressure and the location of its peak along the ship keel as a function of ship and sea characteristics both in regular waves and in rough seas. An approximate method of analysis of whipping stresses, due to slamming, is reported. The method, based primarily upon energy consideration may give the approximate time-history response for a ship hull structure subjected to a slamloading. The second part gives the model scaling requirements in ship slamming phenomena which shall be compiled when testing ship models in tanks in order to obtain meaningful results in so far as full-size prototypes are concerned. In the last part, information on few results available relative to experimental work on whipping stresses due to bottom slamming are reported. In Italian

• Corporate Authors:

  Registro Italiano Navale

  20 Via Vente Settembre
  Genoa,   Italy 
• Authors:
  • Spinelli, L
• Publication Date: 1967-2

Media Info

• Features: Figures; References; Tables;
• Pagination: 37 p.
• Serial:
  • Issue Number: 14

Subject/Index Terms

• TRT Terms: Impact; Pressure; Ship motion
• Old TRIS Terms: Impact pressure; Model testing
• Subject Areas: Marine Transportation; Vehicles and Equipment;

Filing Info

• Accession Number: 00019319
• Record Type: Publication
• Source Agency: Registro Italiano Navale
• Report/Paper Numbers: Tech Rpt
• Files: TRIS
• Created Date: Nov 8 1971 12:00AM