Research database

The service life of a composite material can be improved by proper maintenance and repairing. However, repairing and maintenance incur a considerable amount of downtime. Self-Healing (SH) composites, which are inspired by natural healing systems like human skins, have the capability to autonomously regain their structural integrity and improve their service life. Research on SH composites are thriving in the past few years. SH composites use healing agents, which are encapsulated in thin-walled capsules or vascular networks and are strategically dispersed in the structurally weak matrices or at the interfaces between the matrix and load carrying fibres. The propagating damage bursts the capsules or the vascular networks and releases the healing agent. This will arrest the propagating damage and retain the structural integrity of the composites. The development of new healing agents, designing new healing systems, or the improvement of number of healing cycles achieved by the SH composites are the areas targeted by researchers over the years. The retention of mechanical properties and other structural properties by the SH composites post healing in real structural applications is seldom addressed widely. It is essential to develop a monitoring system for investigating the healing processes and assuring the retention capability of the SH composites. Damages occurring in the inaccessible areas of polymer matrix composites or concrete structures can potentially be healed by the SH composites. However, an in-situ monitoring of the damage progression in these materials and the subsequent healing processes is imperative. The use of advanced Non-Destructive Evaluation (NDE) techniques can identify and localize the damage and healing occurrences. Non-invasive techniques such as Acoustic Emission (AE) technique, optical techniques such as Digital Image Correlation or Electromagnetic techniques such as THz time domain spectroscopy are quite powerful for in-situ process monitoring of large structures. This research proposal aimed at utilizing NDE techniques for monitoring the healing process of the SH composites and to investigate their structural properties post healing. The most advanced AE testing, Optical and Electromagnetic techniques are proposed to be used contemporarily to investigate the healing characteristics of the SH composites thoroughly. Advanced data processing tools and Machine Learning tools are proposed to be used to support the implementation of NDE techniques. Besides, this project also aims at investigating the mechanical and structural behaviour of the SH composites at the damage evolution stages, healing stages and the post healing stages using the advanced NDE techniques. Apart from these, the healing efficiency will also be addressed using these techniques. In a nutshell, the overall aim of this project can be stated as the comprehensive investigation of SH composites in the structural applications using advanced NDE techniques.