Compressive Strength of Hybrid Glass-Basalt Fiber Reinforced Polymer Composite Tube: Multifractal Microstructure Analysis

The object of research is the microstructure of glass-basalt fiber-reinforced polymer (GFRP/BFRP) composite tubes and the relationship between its multifractal dimensions and their physical and mechanical properties. The structure of many materials exhibits heterogeneity across various length scales, which is often assessed through the geometrical characteristics of its elements. However, the complexity of these structural elements poses challenges for quantitative analysis. Method. The study utilized fractal formalism to evaluate the heterogeneous microstructure of GFRP/BFRP composite tubes. The multifractal dimensions of the matrix fibers and epoxy component were analyzed to assess structural heterogeneity. Results. The heterogeneity values were determined using the multifractal spectrum function f(α) for both the matrix fibers and the epoxy component. The sensitivity of the compressive strength of hybrid GFRP/BFRP composite tubes to these heterogeneity indicators ranged from 0.06 to 0.63 for the matrix fibers and from 0.17 to 0.44 for the epoxy component. The correlation coefficients of the fractal models were between 0.75 and 0.81, providing a sufficient level of accuracy for estimating the compressive strength of the tubes. This accuracy supports the interpretation of the proposed method as a non-destructive approach for evaluating the quality of GFRP/BFRP composite tubes.

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