Transient Hydrothermal and Mechanical Stress Intensities around Elliptical Cavities.
Abstract
The transient hygrothermal stresses are determined by assuming that heat and moisture are coupled. A system of coupled diffusion equations is solved by a finite element scheme allowing for time-dependent changes in the moisture and/or temperature on the surfaces of the T300/5208 epoxy resin for the graphite/epoxy fiber-reinforced composite. The time dependent portion of the problem was solved by means of Laplace transformation. Particular emphases are given to the evaluation of transient stresses around a mechanical imperfection in the form of a narrow ellipse. Numerical results are displayed graphically for three different values of the semi-minor to semi-major axis ratio. A stress intensity factor parameter commonly used in fracture mechanics is defined for a narrow ellipse and calculated to investigate the influence of stresses induced by hygrothermal and mechanical disturbances. The radius of curvature of the elliptical cavity can significantly affect the combined stress intensity near the cavity ends. The maximum stress intensities occur at different times depending on the cavity geometry and proportion of the hygrothermal and mechanical loading. These results could shed light on composite failure under conditions where heat and moisture play a role. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1980
- Accession Number
- ADA090625
Entities
People
- Akinori Ogawa
- George C. Sih
Organizations
- Lehigh University