Integrated Sensing, Monitoring and Healing of Composite Systems

Abstract

The ability of a material to recover its nominal properties through self-healing is gaininginterest in the research community. However, current approaches remain predominantly passive incounteracting the effect of damage. As a result, healing only begins when the material has occurreddamage and typically there is a mismatch between the healing and damage rate. For applications suchas aircraft, where there is a thin line between functionality and non-functionality, these limitations maybe inherently restrictive. A self-healing system that combines a prognosis unit to predict and estimatethe failure rate and an active self-healing system that matches the healing rate to the estimated failurerate using a feedback loop, has the potential to overcome these limitations. In this paper we proposesuch a system and present results for its application to composite materials.

A material system with integrated fault diagnosis and feedback controlled self‐healing

“…The self-healing model used is based on previous mathematical formulations. 33,39 The voltage V generated when a force f (t) is applied to an electromechanical material can be expressed using a state-space model equations expressed by ( 14) and (15).…”

“…The adaptive control design is based on a previous formulation. 33,39 First, the modeled self-healing mechanism ( 16) is redefined to include the adaptive control output U(t) to give (18). The input voltage to the polymer electrolyte is now the sum of the voltage V(t) created by the piezoelectric effect in response to the disturbance force and the additional adaptive feedback control voltage U(t).…”

“…The Hölder exponent defines a signal f (x) approximated by a polynomial Z(x) at a local point x 0 , such that the coefficient N and Hölder exponent 𝛼 exist (38). This is used to examine changes in signal by operating on the modulus maxima of the wavelet transform in (37) and is expressed in (39). [47][48][49][50] |f…”

“…Mechanical energy applied to an electromechanical material generates electrical energy which in turn drives the transportation of healing agent for example, copper, nickel and so forth to a damaged area through electrolysis. The self‐healing model used is based on previous mathematical formulations 33,39 . The voltage $$$ V $$$ generated when a force $$$ f(t) $$$ is applied to an electromechanical material can be expressed using a state‐space model equations expressed by () and ().…”

“…Thus, used to control the self‐healing system. The adaptive control design is based on a previous formulation 33,39 …”