The paper presents a theory for prediction of the non-linear vertical response of surface ships in irregular stationary waves. Special treatment is given to the separate predictions of wave-induced hogging and sagging bending moments in ships sailing in moderate head sea. The theory is based on a perturbation procedure in which the linear terms are identical to those of the classical linear strip theories. The quadratic terms arise due to non-linearity of the exciting waves, the non-vertical sides of the ship, and the non-linear hydrodynamic forces. The theory takes into account the flexibility of the ship, which also makes it suitable for an investigation of the possibility of springing vibrations due to non-linear exciting forces. In order to predict the maximum hogging and sagging bending moments in a ship sailing in a stationary, irregular, moderate seaway, a statistical method for handling the present quadratic theory is applied. A numerical example shows the the present theory predicts differences between hogging and the sagging bending moments that are of the same magnitude as those found in full scale measurements.

  • Corporate Authors:

    Royal Technical University of Denmark

    Danish Center For Applied Mathematics and Mechanics
    2800 Lyngby,   Denmark 
  • Authors:
    • Jensen, J J
  • Publication Date: 1978-4

Media Info

  • Features: References;
  • Pagination: 35 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00183349
  • Record Type: Publication
  • Source Agency: Royal Technical University of Denmark
  • Report/Paper Numbers: Report No. 136
  • Files: TRIS
  • Created Date: Nov 14 1978 12:00AM