Sensitivity of composite pipe properties to fractal dimensions

The object of research is the structure of composite pipes and the evaluation of the sensitivity of their fractal dimensions to quality criteria. Method. Mechanical tests were conducted to determine the properties of glass-basalt fiber-reinforced plastic pipes. The experiments included axial tensile and compressive strength tests, as well as elasticity tests. The material composition by mass was 66–70% fiber matrix and 30–34% epoxy binder. Samples were tested in the circumferential direction. The tensile strength in the circumferential direction was measured as the compressive strength as and the axial tensile modulus of elasticity as A multifractal spectrum analysis was performed using a scale resolution ranging from 30 to 300 µm. The calculated sensitivity coefficients for the fractal dimension and were found to exceed by 2–3 times the sensitivity coefficients of other dimensions, such as  and from the Renyi multifractal spectrum of generalized statistical dimensions. Results. The results demonstrate that the fractal dimensions and are the most sensitive indicators for predicting the mechanical properties of composite pipes. These dimensions are recommended for further use in assessing the fiber structure when forecasting mechanical properties. Dimensions with lower sensitivity coefficients, such as and are deemed less significant and are excluded from further quality assessments. This approach provides a robust framework for optimizing composite pipe quality by focusing on the most sensitive structural characteristics, improving both predictive accuracy and resource efficiency.

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