Accession Number : ADA305292

Title :   Wave Propagation in Fiber Composite Laminates. Part 2.

Descriptive Note : Final rept.,

Corporate Author : IIT RESEARCH INST CHICAGO IL

Personal Author(s) : Daniel, I. M. ; Liber, T.

PDF Url : ADA305292

Report Date : JUN 1976

Pagination or Media Count : 137

Abstract : An experimental investigation was conducted to determine the wave propagation characteristics, transient strains and residual properties in unidirectional and angle-ply boron/epoxy and graphite/epoxy laminates impacted with silicone rubber projectiles at velocities up to 250 m per sec (820 ft/sec). The predominant wave is flexural, propagating at different velocities in different directions. In general, measured wave velocities were higher than theoretically predicted values. The amplitude of the in-plane wave is less than ten percent of that of the flexural wave. Peak strains and strain rates in the transverse to the (outer) fiber direction are much higher than those in the direction of the fibers. Strain rates up to 640 E/sec were measured. The dynamics of impact were also studied with high speed photography. The projectile is completely flattened within 50-70 microns. The total contact time is of the order of 300 microns. (AN)

Descriptors :   *IMPACT STRENGTH, *WAVE PROPAGATION, *EPOXY LAMINATES, *GRAPHITE EPOXY COMPOSITES, STRESS STRAIN RELATIONS, STRESS ANALYSIS, HIGH VELOCITY, IMPACT TESTS, TENSILE STRESS, SHEAR MODULUS, DAMAGE ASSESSMENT, FIBER REINFORCED COMPOSITES, STRAIN RATE, RESIDUAL STRESS, FLEXURAL STRENGTH, KINETIC ENERGY, DYNAMIC LOADS, BIAXIAL STRESSES, BORON, PROJECTILE TRAJECTORIES, DYNAMIC PRESSURE, PLANE WAVES, AXIAL LOADS, STRESS WAVES, TRANSVERSE, UNIDIRECTIONAL.

Subject Categories : Laminates and Composite Materials
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE