Shear Strain Singularity-Inspired Identification of Initial Delamination in CFRP Laminates: Multiscale Modulation...

Area of Science:

• Materials Science
• Structural Health Monitoring
• Composite Materials

Background:

• Accurate identification of initial delamination is critical for the safety of fiber-reinforced laminated composite structures.
• Existing multiscale shear-strain gradient (MSG) methods offer physical insight but struggle with obscured damage features due to global components.
• The robustness of multiscale analysis against noise is a key advantage for structural health monitoring.

Purpose of the Study:

• To propose an enhanced approach for identifying initial delamination in fiber-reinforced composite laminates.
• To improve the capacity of MSG for detecting subtle delamination-induced singularities.
• To develop a method that effectively isolates damage features from global structural responses.

Main Methods:

• Development of a multiscale modulation filter (MMF) to refine the MSG.
• Formulation of an enhanced MSG (EMSG) by modulating the original MSG with the MMF.
• Optimization of MMF parameters for frequency translation to concentrate damage features in a narrow wavenumber band.
• Experimental validation using non-contact laser measurement of mode shapes on a carbon fiber reinforced polymer (CFRP) laminate.

Main Results:

• The EMSG effectively isolates the delamination-induced singularity peak from the global component.
• The EMSG concentrates damage features within a specific wavenumber band, enhancing detectability.
• Experimental validation confirmed the graphical characterization of delamination presence, location, and size in CFRP laminates.

Conclusions:

• The proposed EMSG-based approach significantly enhances the identification of initial delamination in composite structures.
• This method provides a more robust and accurate tool for structural health monitoring of fiber-reinforced laminates.
• The EMSG approach offers a reliable means to assess the integrity and safety of composite components by precisely locating and sizing delaminations.