AN EXTENDED STATIC BALANCE APPROACH TO LONGITUDINAL STRENGTH

The procedure suggested to obtain hull design loadings represents a bridge between the conventional static balance method of calculating longitudinal strength and the more rational statistical approaches. This procedure assumes that ship dynamic factors have only a slight influence on longitudinal wave-induced responses. Response amplitude coefficient curves are developed for a ship head-on and upright among trochoidal waves using conventional static balance techniques. The effect of the Smith correction may be included exactly or excluded. A sea spectral density formulation is then used to obtain root-mean-square responses. Statistical estimates of maximum response in probable sea states of wave-induced shear forces and bending moments along the ship are combined with the still water condition and an estimation of whipping effects for design purposes. The procedure can also be based on design criteria of existing basis ships, permitting the same or a proportionate design conservatism to be extended to ships of different materials or geometry. A cumulative fatigue damage theory is used in conjunction with the calculation to estimate limiting stress concentration factors. Agreement with model and full-scale experiments is generally good, even for this greatly simplified mathematical model. ( Author )

• Supplemental Notes:
  • Published in The Society of Naval Architects and Marine Engineers, V N8 P1-34, 13-16 NOV 68
• Corporate Authors:

  Naval Ship Research and Development Center

  Washington, DC  United States 
• Authors:
  • Thomas, Geoffrey O
• Publication Date: 1968-11

Media Info

• Pagination: 43 p.

Subject/Index Terms

• TRT Terms: Bending moments; Electromagnetic spectrum; Hulls; Longitudinal strength; Ship motion; Strength of materials; Vehicle design; Water waves
• Uncontrolled Terms: Ship design
• Old TRIS Terms: Hull strength; Ship response
• Subject Areas: Design; Hydraulics and Hydrology; Marine Transportation; Materials;

Filing Info

• Accession Number: 00001940
• Record Type: Publication
• Source Agency: Defense Documentation Center
• Files: TRIS
• Created Date: Oct 30 1973 12:00AM