Electronic Speckle Pattern Interferometry (ESPI) is a non-contact method used to analyze the vibrational modes of mechanical structures. Due to its ability to precisely map deformations and stress in samples made of various materials, ESPI provides a unique insight into the behavior of materials under dynamic loading. This work focuses on the application of ESPI interferometry in investigating the vibrational characteristics of composite materials based on polyamide (PA) reinforced with carbon fibers in varying weight ratios. The carbon fibers were surface-modified using nitric acid and silica nanoparticles to increase their surface energy and enhance adhesion to the polymer matrix. These modifications contribute to improved mechanical properties of the composite. Based on the analysis of vibrational modes, key material parameters were determined – namely, the tensile modulus of elasticity, Poisson’s ratio, and shear modulus. The obtained vibrational mode results were compared with numerical simulations performed using the Finite Element Method (FEM), which allowed for validation of the measurement accuracy and a better understanding of the dynamic behavior of the composites. The results of this study may contribute to the more efficient design and optimization of composite materials for technically demanding applications in the aerospace, automotive, and mechanical engineering industries.

Acknowledgement: This publication was funded by the European Union NextGenerationEU from the financial resources of the Recovery and Resilience Plan within the Project: The use of the MATLAB program in the processing of experimental scientific data in materials research, code of the project: MVP01_2024; Call for proposal: Early stage grants, Code of the Call: 09I03-03-V05.