Accession Number : ADA301632

Title :   Combined Bearing and Bypass Loading on a Graphite/Epoxy Laminate.

Descriptive Note : Technical memorandum,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CEN TER

Personal Author(s) : Crews, J. H., Jr. ; Naik, R. A.

PDF Url : ADA301632

Report Date : APR 1988

Pagination or Media Count : 37

Abstract : A combined experimental and analytical study was conducted to determine the behavior of a graphite/epoxy laminate subjected to combined bearing and bypass loading. Single-fastener quasi-isotropic specimens were loaded at various hearing-bypass ratios until damage was produced at the fastener hole. Damage-onset strengths and damage modes were then analyzed using local hole-boundary stresses calculated by a finite-element analysis. The tension data showed the expected linear interaction for combined bearing and bypass loading with damage developing in the net-section tension mode. However, the compression bearing-bypass strengths showed an unexpected interaction involving the bearing mode. Compressive bypass loads reduced the bearing strength by decreasing the bolt-hole contact arc and thus increasing the severity of the bearing loads. The bearing stresses at the hole boundary were not accurately estimated by superposition of the stress components for separate bearing and bypass loading. However, superposition produced reasonably accurate estimates for tangential stresses especially near the specimen net-section. (MM)

Descriptors :   *LAMINATES, *FASTENINGS, *GRAPHITE EPOXY COMPOSITES, LOAD DISTRIBUTION, STRESS ANALYSIS, FINITE ELEMENT ANALYSIS, DAMAGE ASSESSMENT, BEARING STRENGTH, HOLES(OPENINGS), COMPRESSIVE PROPERTIES, JOINTS.

Subject Categories : Laminates and Composite Materials
      Couplers, Fasteners, and Joints

Distribution Statement : APPROVED FOR PUBLIC RELEASE