Composites are engineered materials comprised of two individual materials, each with different chemical or physical properties. Used in a wide variety of applications, composites can be designed to exhibit specific material properties that can not be achieved by one material acting alone. In this testing solution, a mesh composite used for making drum heads, was tested in tension to determine the material properties.
Based on testing done in the lab, we recommend a universal testing machine configured with a 5kN load cell and either pneumatic wedge or side action grips. Since the material properties of composites change depending on the materials, the recommended frame and load cell capacity may vary. We used pneumatic side action grips because they provided the constant claiming force required to hold the specimen in place. In addition, we found that when the pneumatic side action grips were configured with wave profile faces it helped to distribute the applied pressure over a large area, resulting in a lower concentration of clamping force and reducing premature failure. When testing composites, we have found that orientation of fibers in the composite have a dramatic effect on mechanical behavior; therefore, precise alignment is critical where slight difference in angle can alter your testing results.
In conclusion, these results show that the gripping techniques were able to accurately measure material properties through failure in each specimen. Due to the variety of composites available this testing solution may not be appropriate for all composites.