UNSTABLE BRITTLE CRACK-ARREST TOUGHNESS OF NEWLY DEVELOPED STEEL PLATE WITH SURFACE LAYERS HAVING ULTRA FINE GRAIN MICROSTRUCTURE (2). CRACK-ARREST TOUGHNESS OF THE PLATE AFTER PLASTIC DAMAGE AND ITS APPLICATION TO PREVENT CRACK EXPANSION AFTER A COLLISION

A new type of steel plate with ultra fine grain surface layers (SUF plate) has been developed to improve crack arrestability. The application of SUF plates with ultra-high crack arrestability has been investigated using both computer simulation for collision of VLCCs and large scale fracture testings for crack arrestability in emergency cases. The computer simulation results suggest that a collision generates significant plastic strain in the area surrounding the struck part. Therefore, the effect of plastic strain (10% level) on crack arrestability in steel plates (the SUF plate and a conventional TMCP plate) was examined by standard ESSO test, and shear strake model fracture test. The test results suggest the following: 1) plastic strain deteriorates crack arrestibility; 2) sufficient crack arrestability at 0 deg. C cannot be expected in the conventional TMCP steel plate with 10% plastic strain induced; and 3) the SUF plate with 10% plastic strain induced possesses high crack arrestability against emergency cases for ships. It is expected that application of SUF plates can prevent serious accidents in which a large amount of oil flows out through hull structural plates damaged by brittle fracture.

  • Supplemental Notes:
    • J Soc Naval Arch Japan, v 178, Dec 1995, p 555 [9 p, 11 ref, 5 tab, 13 fig]
  • Authors:
    • ISHIKAWA, T
    • Inoue, T
  • Publication Date: 1995

Language

  • Japanese

Subject/Index Terms

Filing Info

  • Accession Number: 00728312
  • Record Type: Publication
  • Source Agency: British Maritime Technology
  • Files: TRIS
  • Created Date: Nov 4 1996 12:00AM