A Micromechanics Model Of Thermal Expansion Coefficient In Fiber Reinforced Composites

Abstract

Fiber reinforced composites are widely used for the various applications in the aerospace, automotive, infrastructures and sporting goods industries. The evaluations of its mechanical and thermal properties are needed for accurate estimation of their structural response. In this study, a mathematical closed-form expression of unit cell model was developed to estimate the coefficient of thermal expansion (CTE) along longitudinal and transverse directions of unidirectional lamina. Unlike the previous models, the present model takes into consideration of the fiber configuration and volume fraction of each constituent in the unit cell. In addition, the model is also able to obtain the stresses of the fiber and matrix of unit cell under the temperature environment. The results obtained by present model was validated by ANSY finite model. The parametric study was conducted to better understanding the effect of the CTE's on the fiber volume fraction and fiber configuration. Comparison of the CTE's results obtained by the rule-of-mixture (ROM) and Shapery's model as well as the FEM was conducted. The results of longitudinal CTE are in excellent agreement among all of the models. In the transverse CTE, the present result has better agreement with the FEM result than with the other models. The present results also indicate that changing the fiber configurations does affect the transverse CTE but not longitudinal CTE.