Optimization of Fracture Resistance in Composites
Abstract
An interdisciplinary approach was taken to investigate structure property relationships in fibrous composites subjected to various stress states and environmental conditions. The ultimate goal was to reinforce our ability to optimize the fracture resistance in composites. The concept of controlled interlaminar bonding (CIB) was proposed and evaluated as a possible approach of improving the impact energy-absorbing capability or the damage tolerance in composites. Thickness-direction fibers, as introduced by stitching or braiding, can improve the interlaminar shear strength and interlaminar fracture toughness, thereby reducing or suppressing delamination in advanced composites. Failure mechanisms in the composites subjected to impact loading were investigated. The most critical material parameters that dictate the impact penetration resistance of composites were identified. Failure mechanisms of hybrid composites were studied as a ballistic impact studies was developed. The effect of residual thermal stresses on the impact response of composites was measured. New techniques for determining residuals stresses and internal damages in composites were discussed. A new energy-based fracture criterion for composites was proposed. Equations for determining the strain energy densities in composites under various loading modes were derived. A new way of determining the stress intensity factor in composite was developed, and applications of the J-integral approach to composites fracture problems were discussed.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 21, 1989
- Accession Number
- ADA217431
Entities
People
- Bor Z. Jang
- Bruce Valaire
- Jeff Suhling
- Ralph H. Zee
Organizations
- Auburn University