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Study of Defect Coalescence in Heterogeneous Material Systems Using Broad Band Dielectric Spectroscopy

VAMSEE VADLAMUDI, MUTHU RAM PRABHU ELENCHEZHIAN, PRIYANSHU KUMAR BANERJEE, RASSEL RAIHAN, KENNETH REIFSNIDER

Abstract


Composite materials are essential for many modern applications, including airplanes and cars, energy conversion and storage devices, medical prosthetics, and civil structures. Detecting the initiation, growth, accumulation, and coalescence of micro-damage in these heterogeneous materials and predicting the onset of component failure using conformal Broadband Dielectric Spectroscopy (BbDS) is a promising area of ongoing research. Recently, the authors have developed the critical path concept and Heterogeneous fracture mechanics concept that depicts the effect of defect nucleation, growth, coalescence, and fracture plane development and correlation of these damage mechanisms to change in dielectric response respectively. Current research applies those concepts to detect the damage mode and the critical fracture path (conduction path) that leads to eventual failure. Also, the use of BBDS to detect the weak adhesion bonding is proposed, where the change in dielectric properties as a function of the frequency of the applied potential through the thickness of the sample is measured in the vicinity of the weak region. It is observed that at low frequency the gradient in the potential indicates a spike which marks the charge concentration around the imperfect region.

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