Study on Temperature-Dependent Tensile Strength of Short-Fiber-Reinforced Elastomer Matrix Composites

Abstract

The temperature-dependent tensile strength is an important indicator used to evaluate combination property of short-fiber-reinforced elastomer matrix composite. Some short-fiber-reinforced elastomer matrix composites are manufactured in the molding preparation process, and the tensile tests of fiber, matrix and the composites are carried out at different temperatures. The fiber length and orientation distributions are statistically analyzed. The influence of temperature on the micromechanical stress distribution and transfer in the composite is investigated, and the thermal stresses in the fiber, matrix and fiber-matrix interface are obtained. Based on the theory of micromechanical stress distribution and transfer of the fibrous composite, the mixture law is modified, and a model for predicting the temperature-dependent tensile strength of this kind of composite is developed. Moreover, the mechanism of the tensile fracture of the composite at various temperatures is discussed. Research indicates that the tensile strength is largely related to the temperature, mechanical performances of the main components of the composite and some microstructural parameters, such as short fiber aspect ratio, volume fraction and orientation distribution. The tensile strength of SFRE decreases with increasing temperature. The tensile strength increases with the increase of fiber length when the fiber length is no larger than critical fiber length. There exists a critical fiber volume fraction where the tensile strength of SFRE reaches the maximum. The tensile fracture of the composite depends largely on the temperature, the bond strength of fiber-matrix interface and the average length of reinforcing short fibers. The temperature-dependent tensile strengths predicted by the presented model are in good agreement with experimental data.