Application of different imaging techniques for the characterization of damage in fiber reinforced polymer

Abstract

The heterogeneous and anisotropic nature of fiber reinforced polymers induces the initiation of various damage mechanisms at different scales. Even though full-field surface measurements may successfully track damage development, such approaches do not provide insights into the material bulk. The present work aims at comparing surface and bulk fullfield measurements (via Digital Image/Volume Correlation) for a comprehensive analysis of polymer composite damage. Bulk measurements revealed that damage initiated at the microscale, thus contributing to surface localization phenomena. Full-field surface measurements could not capture the local strain states that the constituents were subjected to, which led to final fracture.

Characterization of glass fiber reinforced polymer via digital volume correlation: Quantification of strain activity and damage growth

“…As the gray level conservation is the underlying hypothesis of DVC [16,17,9], correlation residuals are used for registration quality inspection (i.e., when checking the convergence of the algorithm). As damage phenomena deteriorate gray level conservation, discontinuities and damaged zones for converged displacement fields can be unveiled by studying the correlation residual fields [18,7,19]. The quantification of strained areas and damage growth, as well as the analysis of strain-damage interaction, was thus provided within a single framework.…”

Characterization of glass fiber reinforced polymer via Digital Volume Correlation: Investigation of notch sensitivity

“…( 3), it is regularized with a continuity requirement a priori assumed for the kinematic solution. Additional mechanical knowledge may be implemented to enhance convergence of the algorithm, which is referred to as mechanical regularization based on the equilibrium gap method [19,22,23]. Such an approach enforces the smoothness of measured fields by acting as a low-pass filter that dampens out high spatial frequencies.…”

“…These residuals are probed for all voxels belonging to the studied ROI, and serve as a tool for correlation quality inspection (e.g., when checking the convergence of DVC analysis). Due to the fact that damage growth impairs gray level conservation and consequently DVC convergence, the correlation residuals also provide the means for detecting damage initiation and monitoring damage growth [11,19,24,25].…”

“…The key advantage of such approaches is the availability of correlation residuals corresponding to the gray level difference between the reference volume and the volume of the deformed material corrected by the measured displacement field [7]. Correlation residuals not only provide useful information on the convergence of DVC algorithms, but also unveil discontinuities (i.e., damaged zones) for converged displacement fields [7,19].…”

Braiding procedure and axial compressive behaviors of three-dimensional integrated braided composite three-way circular tubes

“…The strain evolution correlated to the braided structure could be studied. [26][27][28] Results and discussion…”