Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

High-temperature creep with physical and chemical aging, and associated viscoelastic constitutive equations of polyimide-matrix composites

Conference ·
OSTI ID:175127
;  [1]
  1. Univ. of Houston, TX (United States)
The high-temperature creep with physical and chemical aging of a polyimide-matrix composite has been studied with a combined experimental and analytical micromechanics approach. High-temperature aging and creep experiments are carried out to determine the effects of aging on both a neat polyimide (Avimid-N) resin and polyimide-matrix composite. The effect of aging on the polyimide resin is found to be in the form of a volume reduction and a small change in its glass- transition temperature. For both the neat polyimide resin and its composite, aging strains have been distinguished from total high-temperature strains and, thus, true mechanical creep strains can be properly determined. A micromechanics model based on the recently developed homogenization theory is used to study the viscoelastic effective constitutive equations of the composite. The effect of aging-induced property change is taken into account implicitly, through the input neat resin data in the formulation. Comparisons are made between the homogenization predictions and the experimentally obtained effective properties, and good agreement is observed. In the long-term high-temperature creep, it has been found that the complexities associated with the composite microstructural inhomogeneities and imperfection may lead to some discrepancies between the predictions and the experimental results.
OSTI ID:
175127
Report Number(s):
CONF-950686--
Country of Publication:
United States
Language:
English