David E. Havens

Reflexive Composites: Integrated Structural Health Management

Aerospace systems will benefit significantly from the advancement of reflexive composites for increased vehicle survivability. Cornerstone Research Group Inc. (CRG) has developed and demonstrated lightweight, healable composite systems for use as primary load-bearing aircraft components. This technology has the ability to sense and heal damage autonomously during operation. The reflexive system is comprised of piezoelectric structural health monitoring systems, localized thermal activation systems, and lightweight, healable composite structures. The reflexive system is designed to mimic the involuntary human response to damage. Upon impact, the structural health monitoring system will identify the location and magnitude of the damage, sending a signal to a discrete thermal activation control system to resistively heat the shape memory polymer (SMP) matrix composite above activation temperature, resulting in localized shape recovery and healing of the damaged areas. CRG has demonstrated SMP composites that can recover 90 percent of flexural yield stress and modulus after post-failure healing. During the development, CRG has overcome and optimized issues of discrete activation, structural health monitoring integration, and healable resin systems. This paper will address the challenges associated with development of reflexive composites, including integration of structural health monitoring, discrete healing, and healable shape memory polymer resin systems.