NOTCH GEOMETRY AND LAMINATE CONSTRUCTION EFFECTS ON THE FRACTURE TOUGHNESS OF LAMINATES FOR HULL CONSTRUCTION

The effects of notch geometry and ply stacking arrangement on fracture toughness were investigated for fiberglass laminates of chopped fiber mat and woven roving reinforced polyester. The failure stress was found to be insensitive to notch root radius up to a value of approximately 0.10 inches. Except for very large flank angles which approach the unnotched case, the crack flank angle has little effect on the failure stress over a broad range. Since the value of the notch root radius (0.10) in testing is of the same order of magnitude as the length of typical cracks to be anticipated in applications, the validity of classical fracture mechanics is doubtful for this type of composite. A stress concentration approach may provide a more meaningful fracture criterion. The woven roving plies control the toughness of the laminate, and determine the load carrying ability of a flawed member, while both roving and mat plies are significant in determining the tensile strength.

• Corporate Authors:

  Massachusetts Institute of Technology

  Sea Grant Program, 77 Massachusetts Avenue
  Cambridge, MA  United States  02139
• Authors:
  • Bishop, W O
  • Mandell, J F
  • McGarry, F J
• Publication Date: 1973-11

Subject/Index Terms

• TRT Terms: Fracture properties; Glass fiber reinforced plastics; Laminated plastics; Notch tests
• Subject Areas: Marine Transportation; Materials;

Filing Info

• Accession Number: 00057263
• Record Type: Publication
• Source Agency: Massachusetts Institute of Technology
• Report/Paper Numbers: MITSG-73-15
• Files: TRIS
• Created Date: Aug 16 1974 12:00AM