Accession Number : ADA117372

Title :   Transient Hygrothermal Stresses in a Traction Free Slab: Moisture-Temperature-Deformation Coupling Effects.

Descriptive Note : Final rept. 31 Jul 80-30 Jul 81,

Corporate Author : LEHIGH UNIV BETHLEHEM PA INST OF FRACTURE AND SOLID MECHANICS

Personal Author(s) : Sih,G. C. ; Shih,M. T.

Report Date : APR 1982

Pagination or Media Count : 51

Abstract : This effort is a part of the Predictive Response Capability Development program with the objective of incorporating environment effect into design criteria. Previous work has shown that the effects of moisture and temperature interaction cannot be adequately treated by the simple (Fickian) diffusion theory. The coupling between moisture and temperature can significantly influence the resulting stress distribution in the solid, particularly under transient temperature boundary conditions. This paper considers a more complete theory in which deformation of the solid is also assumed to interact with the moisture-temperature diffusion process. The system of governing equations are solved numerically by iteration using Laplace transforms and the technique of finite elements. Coupling effects are analyzed for a traction free slab made of 5208 epoxy resin material subjected to a sudden change of moisture or temperature on the surface. Variations of moisture, temperature and stress with time and space variable are displayed graphically. The influence of coupling is found to vary in both time and space and increases as the specified transient moisture and temperature conditions become more severe. It also tends to delay the time for the hygrothermal stress to reach equilibrium. (Author)

Descriptors :   *Composite materials, *Epoxy resins, *Coupling(Interaction), *Thermal stresses, *Diffusion theory, Finite element analysis, Deformation, Moisture, Temperature, Transients, Modulus of elasticity, Stress strain relations, Traction, Time dependence, Loads(Forces), Fiber reinforced composites, Graphited materials, Stress analysis

Subject Categories : Laminates and Composite Materials
      Plastics
      Numerical Mathematics
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE