Coordinated sensing and active repair for self-healing

Abstract

Self-repairing structural systems have the potential for improved performance ranges and lifetimes over conventional systems. Self-healing materials are not a new phenomenon and have been used in automotive and aeronautical applications for over a century. The bulk of these systems operate by using damage to directly initiate a repair response without any supervisory coordination. Integrating sensing and supervisory control technologies with self-healing may improve the safety and reliability of critical components and structures. This project illustrates the benefit of an integrated sensing, control, and self-healing system using laboratory scale test beds. A thermoplastic polymer embedded with resistive heating wires acts as the self-healing material. Damage is detected using an electro-optical sensing scheme based on photoresistors and a PC handling control duties. As damage occurs it is detected, located, and characterized. The key to this project is the integration of sensor feedback to control healing so that repairs are executed, monitored, and completed on the basis of continuous sensor data. This proof-of-concept prototype can likely be expanded and improved with alternative sensor options, self-healing materials, and system architecture.

Magnetic Field Triggered Multicycle Damage Sensing and Self Healing

“…Thus, the ultimate goal is to create higher forms of materials which can mimic “life” functions 4 . The life functions of damage sensing and healing can increase reliability and service life 5 6 ; triggering these functions remotely and wirelessly is advantageous in industrial and engineering components and coatings, especially in components which are not easily accessible or must remain in situ .…”

Solid-state healing of resins and composites

“…Resistive heating methods have been explored using Surlyn thermoplastic composite systems similar to EMAA, which can sense the damage and locally heat the thermoplastic causing viscous flow and thus healing [55][56][57]. A related approach using ionomer [58] as the HA and a mendable cross-linked network composites used low concentrations of nano-iron oxide particles dispersed in the ionomer to enable healing via induction methods to locally heat the ionomer.…”

Using feedback control to actively regulate the healing rate of a self-healing process subjected to low cycle dynamic stress

“…This means that there is no measure of capturing the incipient cause of damage, no guarantee of matching the healing rate to the damage rate and healing is passively initiated only after damage occurs. Nonetheless, a few works have reported integration of sensing into self-healing processes with the aim of improving the reliability of local detection, diagnosis and efficiency of healing (see table 1 for a summary) [7,[31][32][33][34][35][36]. A damage detection system consisting of a pressure sensor located in a pressurised vascular network and whose output was monitored through a microprocessor was used to trigger the delivery of healing resin from an external reservoir when a crack occurs [7].…”

“…Distributed fibre sensors mounted on a composite plate to detect the pressure drop and initiate the supply of healing agent from an external source has also been reported [31]. In addition to the integrated sensing, an intrinsically driven self-healing material was developed with controlled triggering and healing mechanisms [32]. This consists of a high resistive alloy wire placed in an ethylene vinyl acetate (EVA) thermoplastic material to act as the healing agent.…”