Accession Number : ADA304403

Title :   The Time-Temperature Behavior of Graphite Epoxy Laminates.

Descriptive Note : Doctoral thesis,

Corporate Author : VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG

Personal Author(s) : Yeow, Yew T.

PDF Url : ADA304403

Report Date : 1978

Pagination or Media Count : 159

Abstract : The objective of the present investigation is to provide an in depth study on the time-temperature behavior of epoxy based continuous and elastic fiber reinforced composite materials and explore the possibilities of using the time-temperature analogy as an accelerated characterization method to predict long-term behavior. Both analytical and experimental time-temperature procedures will be presented. The reason for considering only one time analogy is primarily due to the constraints imposed by time limitations which would rule out such a diverse investigation as multi-parametric predictions. However, it is felt that by using the present limited study other environmental parameters can be appropriately and confidently incorporated In future multi-parametric investigations as time permits. The reason for selecting the time-temperature analogy is that among the four analogies, this is the most common and also the most detrimental environmental parameter. In addition, this parameter is one to which epoxy based composite structures are always subjected. Preliminary investigations on the time-temperature behavior of graphite/epoxy laminates indicated that the investigation could essentially be separated into two parts; i.e., room-temperature and elevated temperature responses. At elevated temperatures, especially at or above the glass-transition temperature (Tg), major time-dependent behavior was observed. At room-temperature, only very minor viscoelastic effects were observed.

Descriptors :   *STRESS STRAIN RELATIONS, *EPOXY LAMINATES, *GRAPHITE EPOXY COMPOSITES, TENSILE STRENGTH, STRESS ANALYSIS, TIME DEPENDENCE, HIGH TEMPERATURE, COMPARISON, SHEAR MODULUS, VISCOELASTICITY, FIBER REINFORCED COMPOSITES, THESES, FRACTURE(MECHANICS), ROOM TEMPERATURE, TRANSITION TEMPERATURE, TEMPERATURE GRADIENTS, MATHEMATICAL PREDICTION, STRUCTURAL RESPONSE, THERMAL EXPANSION, CREEP, FAILURE(MECHANICS), THERMAL STRESSES, NOTCH TOUGHNESS, SHEAR STRENGTH, STRESS CONCENTRATION.

Subject Categories : Laminates and Composite Materials
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE