2 - Modeling of self-healing smart composite materials

Abstract

Self-healing smart materials have been under extensive research and development during the past decade. Recent developments in self-healing materials have resulted in a new generation of load-carrying smart material systems with the ability to heal microscale to structural-scale damage. These materials have ranged from polymer matrix composites to ceramic matrix composites, and metal foams and others. The self-healing agent might contribute to the load-carrying capability of the system, or it might only function as a healing agent. One may notice that the major emphasis in this field has been given to experimental studies, and modeling schemes for these systems are still in the development stage. In order to extend the applicability of self-healing smart materials and deploy them in industrial applications, modeling techniques are of utmost importance. Difficulties in manufacturing and testing these new material systems can be compensated for by incorporating modeling techniques such as finite element analysis. It is state of the art to accurately simulate the inelastic, damage, and healing responses of self-healing systems and then construct a virtual design lab for optimizing the performance of these material systems. The mechanical responses of self-healing materials can be categorized into elastic, plastic, damage, and healing deformation mechanisms. In the case of damage-healing mechanisms, the accumulation of microflaws forms damaged sites, and regardless of the type of embedded healing technology, the lost properties of the system in those damaged sites are recovered through the healing functionality. Thus, physically consistent damage and healing models can be considered as basic tools to characterize the performance of self-healing materials. This chapter concerns the recent theoretical developments in the field of continuum damage-healing mechanics of self-healing materials. The mechanisms associated with the damage and healing are used to propose the damage and healing parameters. The evolution laws for the damage and healing processes are developed within the continuum damage-healing mechanics (CDHM) framework, and they are calibrated in accordance with experimentally measurable properties such as changes in the elastic moduli.