FATIGUE CRACK PROPAGATION RATES IN WOVEN AND NON-WOVEN FIBERGLASS LAMINATES

The characteristics of fatigue crack propagation are described for fiberglass laminates containing woven fabric, woven roving, chopped fiber mat, and unidirectional ply reinforcement. The mode of crack propagation is shown to be a stepwise, ligament by ligament advance of the crack front. The rate of crack propagation is predicted to vary exponentially with the stress intensity factor by an approximate theory based on the fracture toughness, unnotched fatigue life curve, and microstructural characteristics. Good agreement is demonstrated between theory and experiment for each material. The relationship between the fatigue crack growth rate and the stress intensity factor can be predicted for a variety of fiberglass laminates by an equation determining crack growth rate for a specified ligament width, using the fatigue life curve as a material property in the simple case of pulsating opening mode loading. The crack growth rate data are normalized to a single relationship for all woven reinforcements, and to a second relationship for non-woven reinforcements.

• Corporate Authors:

  Massachusetts Institute of Technology

  Sea Grant Program, 77 Massachusetts Avenue
  Cambridge, MA  United States  02139
• Authors:
  • Mandell, J F
• Publication Date: 1974-4

Subject/Index Terms

• TRT Terms: Cracking; Fatigue cracking; Fracture mechanics; Glass fiber reinforced plastics; Stresses
• Uncontrolled Terms: Crack propagation; Stress intensity factors
• Subject Areas: Marine Transportation; Materials;

Filing Info

• Accession Number: 00057542
• Record Type: Publication
• Source Agency: Massachusetts Institute of Technology
• Report/Paper Numbers: MITSG 74-21
• Files: TRIS
• Created Date: Aug 28 1974 12:00AM