A curved beam test specimen for determining the interlaminar tensile strength of a laminated composite

Journal Article · Mon Jul 01 04:00:00 EDT 1991 · Journal of Composite Materials; (United States)

DOI:https://doi.org/10.1007/978-94-011-3856-7_22· OSTI ID:6253825

Hiel, C C; Sumich, M; Chappell, D P ^[1]

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1. NASA, Ames Research Center, Moffett Field, CA (United States)

A curved beam type of test specimen is evaluated for use in determining the through-the-thickness strength of laminated composites. Two variations of a curved beam specimen configuration (semicircular and elliptical) were tested to failure using static and fatigue loads. The static failure load for the semicircular specimens was found to be highly sensitive to flaw content, with the specimens falling into two distinct groups. This result supports the use of proof testing for structural validation. Static design allowables are derived based on the Weibull distribution. Fatigue data indicates no measured increase in specimen compliance prior to final fracture. All static and fatigue failures at room temperature dry conditions occurred catastrophically. The elliptical specimens demonstrated unusually high failure strengths indicating the presence of phenomena requiring further study. Results are also included for specimens exposed to a wet environment showing a matrix strength degradation due to moisture content. Further testing is underway to evaluate a fatigue methodology for matrix dominated failures based on residual static strength (wearout). 10 refs.

• OSTI ID: 6253825
• Journal Information: Journal of Composite Materials; (United States), Journal Name: Journal of Composite Materials; (United States) Vol. 25; ISSN JCOMB; ISSN 0021-9983
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
COMPOSITE MATERIALS
EVALUATION
FAILURES
FATIGUE
LAYERS
MATERIALS
MATERIALS TESTING
MECHANICAL PROPERTIES
MOISTURE
TENSILE PROPERTIES
TEST FACILITIES
TESTING