Accession Number:

ADA155925

Title:

Effect of Low-Velocity or Ballistic Impact Damage on the Strength of Thin Composite and Aluminum Shear Panels

Descriptive Note:

Technical paper

Corporate Author:

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CENTER

Personal Author(s):

Report Date:

1985-05-01

Pagination or Media Count:

41.0

Abstract:

Impact tests were conducted on shear panels fabricated from 6061-T6 aluminum and from woven-fabric prepreg of DuPont Kevlar fiberepoxy resin and graphite fiberepoxy resin. The shear panels consisted of three different composite laminates and one aluminum material configuration. Three panel aspect ratios were evaluated for each material configuration. Composite panels were impacted with a 1.27-cm diameter aluminum sphere at low velocities of 46 msec and 67 msec. Ballistic impact conditions consisted of a tumbled 0.50-caliber projectile impacting loaded composite and aluminum shear panels. The results of these tests indicate that ballistic threshold load the lowest load which will result in immediate failure upon penetration by the projectile varied between 0.44 and 0.61 of the average failure load of undamaged panels. The residual strengths of the panels after ballistic impact varied between 0.55 and 0.75 of the average failure strength of the undamaged panels. The residual strengths of the panels after ballistic impact varied between 0.55 and 0.75 of the average failure strength of the undamaged panels. The low-velocity impacts at 67 msec caused a 15- to 20-percent reduction in strength, whereas the impacts at 46 msec resulted in negligible strength loss. Good agreement was obtained between the experimental failure strengths and the predicted strength with the point stress failure criterion. Keywords include Composite materials Shear panels Damage tolerance Low-velocity impact Ballistic damage Postbuckling Helicopter and Fuselage.

Subject Categories:

  • Ballistics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE