Dynamic Behavior of Fiber-Reinforced Composites Under Triaxial Compression

Abstract

Fiber-reinforced composites (FRCs) under transverse impact by bullets are demonstrated to be subjected to the multi-axial stress state. This study presents the dynamic behavior of unidirectional composites at confining pressure. An S-2 glass/SC- 15 composite laminate was manufactured by using a resin injection method and then sectioned into small cylindrical specimens. Optical microscopy was utilized for specimen characterization and the fiber volume fraction was measured. Dynamic experiments were conducted by using a conventional Kolsky compression bar modified by adding a radial and axial confining chamber. Prior to the dynamic loading, hydraulic pressure up to 50 MPa was applied to the two chambers simultaneously. The radial chamber enclosed the cylindrical composite specimen and applied the radial confining pressure. On the other hand, the axial chamber was added at the free end of the transmission bar, providing the axial portion of the hydrostatic pressure to the specimen. Once the triaxial confinement was achieved, a striker impacted the incident bar to apply a dynamic compressive load to the specimen. The specimens’ dynamic responses were compared with that without confining pressure. It is found that the peak strength of the composite increased as the confining pressure increased.