TABLE OF CONTENTS The fabrication process of composite materials may introduce reversible and irreversible effects due to the processing thermal cycle and chemical changes and due to the mismatch in thermal properties of the constituents. The most common manifestation of these effects are residual stresses and warpage.
After fabrication, composite structures operate in a variety of thermal and moisture environments that may have a pronounced impact on their performance. These hygrothermal effects are a result of the temperature and moisture content variations and are related to the difference in thermal and hygric properties of the constituents.
Processing and environmental effects are similar in nature. They can be viewed and analyzed from the microscopic point of view, on the scale of the fiber diameter, or from the macroscopic point of view, by considering the overall effects on the lamina, which is treated as a homogeneous material.
Analysis of the processing and hygrothermal effects is an important component of the overall structural design and analysis. The performance of a composite structure is a function of its environmental history, temperature and moisture distributions, processing and hygrothermal stresses, and property variations with temperature and moisture. Hygrothermal effects can be categorized as follows:
Moisture absorption and desorption processes in polymer/matrix composites depend on the current hygrothermal state and on the environment. [1] The glass transition temperature of the polymeric matrix varies with the moisture content. Polymerization processes are a function of the hygrothermal properties of the constituent materials and the...
