Test Methods for Measuring Material Properties of Composite Materials in all Three Material Axes

Material properties were determined for fiber-reinforced polymers (FRPs) with respect to all three material orientations using existing ASTM standards when applicable. Determining strength and stiffness properties both in-plane (load applied parallel to fiber orientation) and out-of-plane (load applied perpendicular to fiber orientation) is important in designing for ballistic protection. Shear strength, shear modulus, compressive strength, compressive modulus, tension strength, tensile modulus, and Poisson’s ratio were all measured in the plane of the fibers and out-of-plane. In order to measure certain out-of-plane material properties, unique testing standards were developed. Test standards that are available for obtaining out-of-plane properties are tedious to perform particularly since premature failures occur at bonds between the composites and fixtures. In addition, there are currently no existing standards intended for measuring out-of-plane compressive properties and Poisson’s ratio. Finally, materials tested in this research had a defined thickness ranging from 1.91 cm to 3.81 cm which caused conflicts with existing standards meant to be performed with longer specimens. This paper provides solutions for measuring each material property by summarizing all testing and fabrication procedures required