Laminated plates are one of the simplest and most widespread practical applications of composite materials. Glass roving cloth/polyester composite plates with three ply laminas are impacted and damaged by foreign projectiles, such as steel balls or steel rods fired from an air gun. All the present experiments are conducted at speeds below the critical speed required for perforation. In this speed range, it is observed that the dominant energy absorbing fracture mechanisms are delamination between laminas and debonding between fibers and a matrix. Both fracture mechanisms are observed in the same square area with its diagonals in 0-90° fiber directions. It is found that the total damaged area and the initial kinetic energy of the projectile have a linear relationship. Finally, the explanation of the linear relationship is tried out in terms of the energy.
Recently developed substrateless continuous SiC filament is expected to be a new reinforcing filament for composite materials. In order to apply this filament to fiber reinforced metals, strength properties at both room and elevated temperatures were examined. Room temperature tensile strength showed no strain rate dependence, while it showed gauge length dependence to the similar degree as those of chemical-vapor-deposited SiC filaments. In-air tensile strength at elevated temperatures was in the range of reported data for chemical-vapor-deposited tungsten-substrate filaments. Significant improvement in room temperature tensile strength by acid treatments was not observed.
The distribution of constituents at the interfaces in several kinds of composites was examined by EPMA. Two kinds of stainless steel wires were used as the reinforcements. Aluminium and aluminium alloy of duralumin type were used as the matrices. Two processes, dipping in air and casting in a vacuum, were employed for fabrication. A X-ray intensity character at the interface was similar in all specimens. It is expected that there is an intermetallic compound. The diffused constituents were detected in the matrices 1, 000μm apart from the interfaces. In the case of the aluminium alloy, segregation of Cu was detected at the interface.