The Effect on Fiber Properties on Resin-Fiber Interfacial Property Evaluated through Microdroplet Pull-out Testing

Composite materials have become essential structural materials in various industries, such as aerospace, automotive, marine, and wind energy, where lightweight and high-strength properties are critical. To ensure the structural stability of these composites, quantitative evaluation and optimization of interfacial strength are essential. Interfacial strength serves as an indicator of bonding force and load transfer efficiency between the matrix and reinforcement, significantly impacting the overall performance of composites. In this study, we assessed interfacial strength using the micro-droplet pull-out test with carbon fiber and analyzed the influence of fiber mechanical properties on interfacial strength evaluation. The tensile strength and modulus of carbon fiber were determined through single-fiber tensile testing, and micro-droplet specimens with various embedment lengths were fabricated for pull-out tests. The results revealed that the mechanical properties of the fiber play a critical role in the reliability and accuracy of interfacial strength evaluation. This study provides fundamental data for composite design and interfacial optimization, and it is expected to contribute to improved accuracy in interfacial strength assessments for various reinforcements.