Abstract:
Fiber-reinforced composite materials are increasingly used in rotorcraft structures to reduce weight and improve efficiency. A major challenge, delaying the implementation of recently developed higher-performance materials that offer improved mechanical strength and stiffness at a lower weight, is the lack of efficient common material qualification. The current standard practices are too costly and time-consuming. Due to low confidence in material allowables, the entire material qualification process, including numerous test methods and large test matrices, must be repeated for every seemingly minute change in the composite system. This work presents initial results of research activities under the National Rotorcraft Technology Center, focused on utilizing recent advances in understanding complex deformation and failure mechanisms of polymer-matrix composites towards the development of consolidated common analysis processes. These common processes will enable reduced material qualification test matrices potentially accommodating substitution of resin types and other modifications of the material systems. In particular, analysis methods, developed at the University of Texas Arlington Advanced Materials and Structures Lab, are verified on carbon-fiber reinforced / untoughened and toughened polymer-matrix composite material systems. Due to well-recognized susceptibility of polymeric composites to matrix-dominated failures, thorough verification of the analysis methods using a range of the matrix types is required for improving confidence in the analysis-based material allowables accelerating material qualification.