Smart Self Sealing Pressure Vessels and Structural Panels

Structural systems that autonomously repair damage have the potential for enhanced longevities and performance envelopes. This paper addresses the issue of autonomously sensing and controlling self-repair processes in structural systems. Such an approach has the potential to expand upon self healing materials technology to the development of engineered smart self-healing structural systems. This involves coordinating damage-sensing capabilities with control of the healing processes. Much of the conceptual underpinning of this work comes from biological systems that routinely combine sensing with healing actions that span multiple spatial and temporal scales. The specific details and modalities of the response depend on the extent and vital threat of the damage. Coordination of antagonistic repair and material remodeling processes with a self-aware sense of health is an essential part of the process. This paper describes the results of experimental and system development efforts that attempt to mimic some aspects of coordinated self-healing in structural systems. This research expands and demonstrates the enhancement of autonomous repair techniques through the coordinated damage sensing and directed repair activities with test bed pressure vessels and structural panels that have been damaged by puncture and drilling of holes. Acoustic emission, embedded optical and capacitance sensors detect the damage. Thermoplastic repair techniques are initiated upon repair detection and localization of damage. Autonomous leak repair in pneumatic pressure vessels and panels with perforations up to 3 mm upon detection and localization of the damage are demonstrated.