Accession Number : AD0718978

Title :   Viscoelastic Behavior of a Nonlinear Fiber-Reinforced Plastic.

Descriptive Note : Final rept. 1 Feb 67-30 Nov 69,

Corporate Author : PURDUE RESEARCH FOUNDATION LAFAYETTE IND

Personal Author(s) : Lou,Y. C. ; Schapery,R. A.

Report Date : MAY 1970

Pagination or Media Count : 86

Abstract : The nonlinear, viscoelastic behavior of a unidirectional, glass fiber-epoxycomposite material is characterized by using isothermal, uniaxial creep, andrecovery tests together with a constitutive equation based on a thermo-dynamictheory. Linear stress-strain equations for both uniaxial and multiaxialloading of orthotropic materials are reviewed, and then the non- inearconstitutive equation for uniaxial loading is given. The creep complianceobeys a power law in time with the exponent being independent of fiberorientation and stress level, and the nonlinear properties depend mainly onthe average octahedral shear stress in the matrix. These properties are usedto make various predictions of viscoelastic behavior, and good agreement withthe experimental data is found. A limited study of the effect of temperatureon creep is made. (Author, modified-PL)

Descriptors :   (*REINFORCED PLASTICS, *VISCOELASTICITY), COMPOSITE MATERIALS, GLASS TEXTILES, EPOXY RESINS, LOADS(FORCES), SHEAR STRESSES, STRAIN(MECHANICS), CREEP

Subject Categories : Laminates and Composite Materials
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE