Relationship of dielectric property change to composite material state degradation

Abstract

a b s t r a c tPolymer matrix composites are widely used in many industries, i.e. aerospace, microelectronics, energy storage etc., because of their unique properties and performance. During their service life, changes of material state caused by deformation and damage accumulation under combined mechanical, thermal and electrical fields requires fundamental understanding to support design of those material systems. Heterogeneous material systems are inherently dielectric as determined by their complex morphology. Dielectric properties of such materials are altered by many factors, e.g., electrical and structural interactions of the particles, and the shape, orientation and distribution of the constituents of the material system. When damage occurs, new phases are created as micro-defects, and grow progressively, interact, and accumulate. The dielectric properties of the composite system also change in a manner that uniquely reflects those details. In the present work we report a non-invasive, in-operando technique to study changes in dielectric properties during progressive damage accumulation in composite materials subjected to mechanical loading.

Enhanced dielectric properties of poly(vinylidene fluoride)–surface functionalized BiFeO3 composites using sodium dodecyl sulfate as a modulating agent for device applications

“…Second, a sharp rise in the conductivity curves at higher frequency region is attributed to the fast movement of charge carriers with the application of high electric field. It is because when we are applying a high electric field to the polymer‐ceramic composites maximum numbers of charges are migrated to the ceramic interface …”

Multiphysics Based Simulation of Damage Progression in Composites

“…Using in-situ tensile testing, Raihan et al [11] induced damage in an off-axis plain weave E-glass fabric combined with epoxy resin matrix and performed dielectric studies on the samples to get real time response with damage as shown in Figure 3(a). Also, a novel edge replication technique was used to observe the damage progression with increasing load as shown in Figure 3 In this paper we induce damage in the specimen and capture the change in material state using the concept of "Heterogeneous" fracture mechanics and predict the "beginning" of end of life.…”

“…Haider [10], Raihan et al [11] [12] [13], Bekas et al [14] have demonstrated the capability of this technique to characterize and detect damage in composite material systems. Most recently, Reifsnider et al [15] have postulated the concept of a "critical" path generated by coalescence of various defects and mechanisms.…”

Validated predictive computational methods for surface charge in heterogeneous functional materials: HeteroFoaM™

“…In a series of previous publications, we have applied equation (3) to some of the complex microstructures illustrated in Figure 1 at the conformal level, and have included electrochemical effects on the resulting flux terms shown in that equation. However, in this publication, we are only concerned with constructing a predictive method for time dependent electric charge distribution (including surface charge) in heterogeneous materials at the fundamental level, and the validation of such a method (Liu 2012;Liu 2011a;Reifsnider et al 2013;Baker et al 2014;Liu 2011b;Raihan et al 2014). Therefore, without loss of generality for the present discussion, we neglect all source terms and concern ourselves with the following simplified version of Eq.…”