Material State Awareness for Composites Part II: Precursor Damage Analysis and Quantification of Degraded Material Properties Using Quantitative Ultrasonic Image Correlation (QUIC)

Abstract

Material state awareness of composites using conventional Nondestructive Evaluation (NDE) method is limited by finding the size and the locations of the cracks and the delamination in a composite structure. To aid the progressive failure models using the slow growth criteria, the awareness of the precursor damage state and quantification of the degraded material properties is necessary, which is challenging using the current NDE methods. To quantify the material state, a new offline NDE method is reported herein. The new method named Quantitative Ultrasonic Image Correlation (QUIC) is devised, where the concept of microcontinuum mechanics is hybrid with the experimentally measured Ultrasonic wave parameters. This unique combination resulted in a parameter called Nonlocal Damage Entropy for the precursor awareness. High frequency (more than 25 MHz) scanning acoustic microscopy is employed for the proposed QUIC. Eight woven carbon-fiber-reinforced-plastic composite specimens were tested under fatigue up to 70% of their remaining useful life. During the first 30% of the life, the proposed nonlocal damage entropy is plotted to demonstrate the degradation of the material properties via awareness of the precursor damage state. Visual proofs for the precursor damage states are provided with the digital images obtained from the micro-optical microscopy, the scanning acoustic microscopy and the scanning electron microscopy.

Nonlocal Damage Mechanics for Quantification of Health for Piezoelectric Sensor

“…A frequency domain response of the impulse excitation has a broadband spectrum. A pulse is usually applied to the electrode having a short duration compared to the time associated with the Rayleigh waves to pass between two finger length [39]. As the electric field is reversed at each interval between figures, the transmitted signal has a spatial period of 2d.…”

“…The above concept is mathematically formulated and key aspects are discussed below. Patra and Banerjee have employed the similar theoretical model to quantify the precursor to damage in woven carbon composite structure damage under influence of high cycle fatigue loading [39].…”

Structural state awareness through integration of global dynamic and local material behavior

“…A major driver of NDI/SHM research is detection of damage earlier in service life in order to prevent failures, change use, or schedule repair (Farrar and Worden, 2007;Rabiei et al, 2016;Sangid, 2013). Examples of measureable precursors to fatigue crack development may involve changes in acoustic energy (Arguelles et al, 2016;Baby et al, 2008;Turner, 2015, 2016;Lissenden et al, 2014;Malfense-Fierro, 2014;Patra and Banerjee, 2017), electric and magnetic field lines (Atulasimha and Flatau, 2011;Clark, 2000;Dobmann et al, 2006;Gao et al, 2009;Garcia-Martin et al, 2011;Haile et al, 2016;Matlack et al, 2014;Nagy and Hu, 1998;Scheidler et al, 2015), material compliance (Cole et al, 2017a(Cole et al, , 2017bWakha et al, 2005), optical changes (Pang et al, 2012(Pang et al, , 2013, or electromagnetic scattering (Patra and Banerjee, 2016;Si et al, 2011;Weder, 2009). 1.2 Energy state in fatigue Morrow (1965) and Halford (1966) calculated the energy dissipation due to plastic deformation during fatigue loading to establish a criterion for fatigue damage, which was an early consideration of fatigue damage precursors.…”

Effect of Defects Part I: Degradation of Constitutive Coefficients as an Input to the Composite Failure Model with Microvoids and Porosity

“…Manufacturing defects are inevitable in all composite materials due to resin transfer molding (RTM) or chemical vapor infiltration (CVI) processes [6]. During the operation of in-service composites, the early-stage defects evolve during the first 30% of their lifespan [7,8]. Microvoids are the most common manufacturing and in-service defects that occur in composite materials.…”