STP636: Designing for Integrity in Long-Life Composite Aircraft Structures

    Walter, RW
    Senior specialist engineer, senior research engineer, engineering supervisor (BAC), and engineering supervisor (BCAC), The Boeing Company, Seattle, Wash

    Johnson, RW
    Senior specialist engineer, senior research engineer, engineering supervisor (BAC), and engineering supervisor (BCAC), The Boeing Company, Seattle, Wash

    June, RR
    Senior specialist engineer, senior research engineer, engineering supervisor (BAC), and engineering supervisor (BCAC), The Boeing Company, Seattle, Wash

    McCarty, JE
    Senior specialist engineer, senior research engineer, engineering supervisor (BAC), and engineering supervisor (BCAC), The Boeing Company, Seattle, Wash

    Pages: 20    Published: Jan 1977


    Abstract

    Results of test programs conducted to obtain structural performance information essential to the design of long-life composite aircraft structure are presented. Static, fatigue, and fracture tests were conducted on T300/5208 and T300/5209 graphite/epoxy laminate specimens which were representative of full-scale strength-designed laminates. Results showed that static tensile and compressive strength are significantly degraded by discontinuities and impact damage. Laminates with representative fiber damage are relatively insensitive to cyclic tensile loadings; however, cyclic compressive loading results in finite fatigue lives. Impact damage which caused barely visible fiber failure was found to reduce fatigue performance below that defined for an open hole. The graphite/epoxy laminates tested were found to be fracture sensitive. Laminate stacking sequence was found to have a significant influence on fracture strength and failure mode.

    Keywords:

    material properties, fracture (materials), fatigue (materials), composite materials, composite structure, impact strength, damage tolerance (mechanics), residual strength


    Paper ID: STP27980S

    Committee/Subcommittee: D30.04

    DOI: 10.1520/STP27980S


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