Accession Number:

ADA429880

Title:

Fracture Toughness Improvement of Composites Reinforced with Optimally Shaped Short Ductile Fibers

Descriptive Note:

Final rept. 1 May 2001-31 Dec 2004

Corporate Author:

STATE UNIV OF NEW YORK AT ALBANY RESEARCH FOUNDATION

Report Date:

2001-01-01

Pagination or Media Count:

9.0

Abstract:

The fracture toughness of brittle matrix composites reinforced with ductile fibers has been greatly improved by shaping the fibers so that they fully contribute their plastic work to the fracture process. This has been accomplished by anchoring the fiber ends so that the largest possible fiber volume contributes to the toughness during pullout. A combined experimental and analytical program has shown that it is possible to organize fibers into shape families and to optimize the toughness with respect to geometric parameters within a given shape family. The interface conditions during pullout have been modeled using a new cohesive zoneCoulomb friction model with three parameters. Furthermore, adaptive methods in space and time were developed to reduce computational time. New indicators for error in spatial and temporal discretizations were derived and implemented. Once these parameters were inferred from one embedded length from the single fiber pullout test SFP, predicted pullout toughness values at other embedded depths matched well with experimental results. In addition, fracture values predicted from SFP tests matched well with experimental composite fracture values. A list of 19 publications and technical reports on this topic and a bibliography are included.

Subject Categories:

  • Laminates and Composite Materials
  • Metallurgy and Metallography
  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE