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2020 Research Highlight: Real-time Damage Characterization for Glass Fiber Reinforced Composites

Real-time Damage Characterization for Glass Fiber Reinforced Composites

Mr. Jinling Gao
Purdue University
Prof. Wayne Chen
Purdue University
Mr. Xiaofan Zhang
Johns Hopkins University
Prof. Somnath Ghosh
Johns Hopkins University
Mr. Jian Gao
Drexel University
Prof. Giuseppe R. Palmese
Drexel University
Mr. Christopher S. Meyer
CCDC Army Research Laboratory,
University of Delaware
Prof. Bazle Z. Haque
University of Delaware
Prof. John W. Gillespie, Jr.
University of Delaware
Dr. Daniel J. O’Brien
CCDC Army Research Laboratory

We integrate the high-speed synchrotron X-ray phase contrast imaging capabilities available at APS Beamline 32 ID-B into the dynamic single-edge notched bending experiment on the composite beam. The experiment is performed on a modified Kolsky compression bar platform by impacting the specimen installed at the incident bar end onto a static indenter at a constant velocity. The load on the indenter is directly measured by a load cell to replace the transmission bar, whilst the deflection of the composite beam is determined by stress wave passing the strain gauges on the incident bar surface. During loading, synchrotron X-ray penetrates the specimen from side and recognizes damage-related features developed inside composite. The X-rays with the damage information are then transferred to the visible light by a scintillator, magnified by a 5X objective lens and finally projected to the high-speed camera for imaging. Composites investigated are unidirectional and cross-ply S-2 glass fiber reinforced two matrix systems as commercialized SC-15 and newly developed ductile TGDDM-Jeffamine® D230 matrix modified by monoamine functionalized partially reacted substructures (mPRS), respectively. The experimental technique is revealed to have micrometer resolution to identify the crack initiation at 20-μm scale level within 200 ns and damage-related features down to 10 μm scale, such as fiber/matrix transverse debonding, fiber bridging. Moreover, it is capable of tracking the damage evolution inside and between individual plies of laminated composites.

The Parametrically Homogenized Continuum Damage Mechanics (PHCDM) models, validated by the above experimental observations, are developed to provide more quantitative information such as local stress and strain distributions, damage evolution, and detailed microscopic failure behaviors. In PHCDM models, the macroscopic constitutive laws are entirely based on micromechanical responses, therefore, the effects of microscopic information can be explicitly incorporated into the constitutive parameters through representative aggregated microstructural parameters (RAMPs). This multi-scale modeling scheme enables material-by-design from microscopic level while being computationally efficient for structure level analysis.