Strength Degradation of Filament-Wound Graphite/Epoxy Tubes Due to Either Impact Damage or Fabrication Defects
Abstract
Two test series were conducted to assess the strength degradation of filament-wound graphite/epoxy tubes caused by impact damage or fabrication defects. The defects were either helical wrinkles or a hoop wrinkle inside the tube walls. The baseline tube configuration had a nine-ply (+10 deg, -10 deg, 90 deg)3 lay-up, with the exception of one tube having a (+15 deg, -l5 deg, 90 deg, 90 deg)3 stacking sequence. The latter lay-up configuration was to induce helical fiber-dominated failure. The tubes were subjected to either pneumatic or hydrostatic internal pressure, creating a biaxial stress state in the tube walls. The test results show that the burst pressure decreases significantly with increasing impact force for impact-damaged tubes. For impact loads of 823 to 1470 N (185 to 330 lb), the burst pressure dropped by 24% to 32%, respectively, compared to those with no impact damage. Most failures initiated at the impact locations. Some originated from locations other than the impact sites. For the wrinkle-defect specimens, minor helical wrinkles had no measurable effect on the burst pressure. More severe helical wrinkles decreased the burst pressure by 8%. Hoop wrinkles caused a significant degradation in strength (14% on average).
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 2004
- Accession Number
- ADA426853
Entities
People
- D. J. Chang
- H. A. Katzman
Organizations
- The Aerospace Corporation