Inverse determine the interfacial strength and surface geometry effects concerning carbon fiber reinforced epoxy composites by experiment aided FFT‐based spectral analysis

Abstract The interfacial strength of carbon fiber reinforced epoxy composites is determined inversely by the combination of the transverse fiber bundle tensile experiment and fast Fourier transforms based spectral method. A representative volume element with transverse random fiber distribution is established to predict the strength of the composites, where the nanoscale interphase region between fiber and matrix is discretized by multi‐layer pixels. The interfacial stiffness is described by an exponential function, while the interfacial strength is a variable input. By using the spectral method, the interfacial strength of composites with different fiber types is analyzed rapidly. The effects of fiber modulus and interfacial geometric features (including interface topology and interphase thickness) on the mechanical behaviors and interfacial strength inversion are investigated to reveal the interface enhancement mechanisms. This study can be greatly helpful for interface design and performance evaluation of new‐type carbon fiber reinforced composites in engineering application.