Theoretical Prediction Method for Tensile Properties of High-Strength Steel/Carbon Fiber-Reinforced Polymer Laminates

This study introduces a method for predicting the tensile properties of high-strength steel/carbon fiber-reinforced polymer (CFRP) composite laminates using Metal Volume Fraction (MVF) theory. DP590 and DP980 high-strength steels (thickness ~0.8 mm) were selected as substrates, and composite laminates were fabricated by compression molding with CFRP prepreg. Tensile tests were performed on an MTS universal testing machine, and fracture morphology was analyzed using scanning electron microscopy (SEM). The results demonstrated a typical mixed failure mode: necking and fracture in the metal layer, and neat fiber fracture in the CFRP layer. Comparisons of experimental tensile strength with theoretical predictions revealed that the model based on the metal strength at fracture significantly outperformed the model using tensile strength for predictions, with narrower error ranges. For example, the error for DP590/CFRP laminates ranged from 2.31% to 12.89%, whereas for DP980/CFRP laminates, it was -6.12%. Additionally, the study showed that using metals with higher plasticity in fiber metal laminates could underutilize the metal layer's potential at peak stress, leading to significant deviations when predictions rely on tensile strength. Therefore, it is recommended to use the metal strength corresponding to peak stress for more accurate MVF-based tensile property predictions. This method provides a robust theoretical foundation for predicting the tensile performance of high-strength steel/CFRP laminates, aiding in optimizing structural designs for automotive and aerospace applications. Future research could explore the effects of different metal and fiber combinations, as well as more complex stacking designs.