Optimizing multilayer perceptron (MLP) hyperparameters via covariance matrix adaptation evolution strategy (CMA-ES) for predicting composite bending behavior
摘要
This study presents a comprehensive experimental and AI-based investigation into the three-point bending behavior of aramid and glass fiber-reinforced hybrid composites, considering different EKabor-II nanoparticle reinforcement levels (0 wt%, 0.5 wt%, and 1 wt%). Artificial Neural Networks (ANN), Classification Learner, and Regression Learner algorithms are comparatively applied for the first time to predict the mechanical responses of composite panels with millimeter-level precision. The ANN model, trained using Levenberg–Marquardt with 5 neurons and a learning rate of 0.013, achieved a validation MSE of 0.678 MPa and R2 of 0.9997. Meanwhile, the Gaussian Process Regression (GPR) method produced outstanding results (RMSE = 0.089 MPa, R2 = 0.9999). Hyperparameter optimization using the CMA-ES algorithm eliminated the need for manual trial-and-error, objectively identifying the optimal ANN configuration and enhancing global search capability and generalization reliability. Five-fold cross-validation and 95% confidence intervals (RMSE = 0.75 ± 0.83 MPa; R2 = 0.9869 ± 0.0039) demonstrate consistent performance beyond randomness. SHAP-based explainability analysis revealed that compressive load (55% contribution) and test duration (20%) dominantly influence flexural stress, enabling causal interpretation of the model. Edge-case analysis under extreme configurations (Wt = 0, Wt = 1, and maximum compressive load) confirmed prediction deviations within ± 5 MPa, ensuring safety margins. This holistic approach significantly contributes to accelerating computational materials design and establishing reliable infrastructures for Industry 4.0, digital twin, and sustainable (eco-composite) applications in materials science and engineering.