Stress Transfer in High Performance Polyethylene Fiber Reinforced Epoxy Resin Composite Analyzed by X-Ray Diffraction

In the Direction Parallel to the Fiber Axis

Abstract

Stress transfer parallel to the axis of high performance polyethylene fibers in a fiber reinforced epoxy resin composite was investigated by X-ray diffraction. Internal stress σ_f in the embedded fiber could be measured by monitoring the longitudinal strain of the crystalline regions of polyethylene by X-ray diffraction. The stress σ_f increased linearly with external stress applied to the composite. This behavior was in agreement with the rule of mixture of mechanical reinforcement and independent of interfacial adhesion. The mechanical reinforcement was dependent on the mechanical properties of both fiber and matrix, and also a fiber volume fraction. Interfacial adhesion and the existence of fiber ends influenced the mechanical properties of large deformation such as tensile strength. The “X-Ray Diffraction Method” proved to be a powerful tool for detecting the stress on the incorporated fiber in the loaded composite in situ and non-destructively.