SYMPOSIA PAPER Published: 01 January 1982
STP29387S

Fracture Characterization of a Random Fiber Composite Material

Source

A short-glass fiber composite materials, SMC-R50, was tested under uniaxial loading at ambient temperature and humidity conditions over two orders of magnitude of loading rate. The test method, experimental results, and analytical characterization of fracture behavior are described. Baseline information on the strength of 1.27-cm and 2.54-cm wide unnotched tension specimens indicate that effects of size and test orientation (relative to molding orientation) are not significant. Fracture behavior of notched samples was studied on specimens of two different widths (2.54 and 5.08 cm); each sample had two symmetrically cut, crack-like notches. For each sample size, the effect of four different notch lengths and loading rates on ultimate strength, ultimate strain, and the overall stress-strain curve were investigated. Loading rate was found to have no significant effect on sample response. The stress-strain curves of notched and unnotched samples in terms of nominal stress σ and strain ϵ obey the power law σ ∼ ϵ0.78 out to failure. In spite of this nonlinearity, it was possible to characterize the fracture stress behavior using linear elastic fracture mechanics theory and a constant fracture toughness. The effect of notch length on sample compliance and on failure strain was found to obey this theory if ϵ0.78 is used in place of ϵ.

Author Information

Alexander, RM
Texas A&M University, College Station, Tex.
Schapery, RA
Texas A&M University, College Station, Tex.
Jerina, KL
Texas A&M University, College Station, Tex.
Sanders, BA
General Motors Technical Center, Warren, Mich.
Price: $25.00
Contact Sales
Related
Reprints and Permissions
Reprints and copyright permissions can be requested through the
Copyright Clearance Center
Details
Developed by Committee: E08
Pages: 208–224
DOI: 10.1520/STP29387S
ISBN-EB: 978-0-8031-4837-6
ISBN-13: 978-0-8031-0697-0