STP568

    Impact Response of Graphite-Epoxy Flat Laminates Using Projectiles that Simulate Aircraft Engine Encounters

    Published: Jan 1975


      Format Pages Price  
    PDF Version (568K) 23 $25   ADD TO CART
    Complete Source PDF (5.2M) 23 $75   ADD TO CART


    Abstract

    An investigation of the response of a graphite-epoxy material to foreign object impact was made by impacting spherical projectiles of gelatin, ice, and steel normally on Modmor II/PR-286 flat panels. The observed damage was classified as transverse (stress wave delamination and cracking), penetrative, or structural (gross failure): the minimum, or threshold, velocity to cause each class of damage was established as a function of projectile characteristics. Steel projectiles had the lowest transverse damage threshold (30 m/s), followed by gelatin (170 m/s) and ice (215 m/s). Making use of the threshold velocities and assuming that the normal component of velocity produces the damage in non-normal impacts, a set of impact angles and velocities was established for each projectile material which would result in damage to composite fan blades. Analysis of the operating parameters of a typical turbine fan blade shows that small steel projectiles are most likely to cause delamination and penetration damage to unprotected graphite-epoxy composite fan blades.

    Keywords:

    graphite composites, epoxy resins, impact tests, composite materials, fiberglass reinforced plastics, fractures (materials), tests, damage, evaluation


    Author Information:

    Preston, JL
    Senior materials engineer and assistant project engineer, United Aircraft Corporation, Middletown, Conn.

    Cook, TS
    Senior materials engineer and assistant project engineer, United Aircraft Corporation, Middletown, Conn.


    Paper ID: STP33150S

    Committee/Subcommittee: D30.02

    DOI: 10.1520/STP33150S


    CrossRef ASTM International is a member of CrossRef.