Multiple Input–Single Output (MISO) framework for Low Velocity Impact Response of Hybrid Gongronema latifolium/S-Glass Fiber Epoxy Composites

The development of sustainable composite materials for impact-critical applications is increasingly important in aerospace, automotive, and defense sectors. This study employed a quantitative experimental approach using a Multiple Input–Single Output (MISO) framework to examine how hybridization ratio, mass fraction, and fiber orientation affect the low-velocity impact response of Gongronema latifolium/S-glass fiber-reinforced epoxy composites. Processed Gongronema fibers and S-glass were combined with ER-F292 epoxy resin and fabricated into test samples following ASTM standards. Charpy impact tests assessed energy absorption. A 60-run optimal design captured combinations of the three input variables. Data were analyzed using a Multiple Linear Regression model via SPSS to determine statistically significant predictors of impact behavior, using p-values and confidence intervals for validation. Results showed that the mean values for hybridization ratio, mass fraction, fiber orientation, and low velocity impact were (2.50), (27.79%), (67.90°), and (3.82 J), respectively. It was found that the mass fraction had a significant negative correlation with low velocity impact (r = -0.455; p = 0.000), as did the fiber orientation (r = -0.853; p = 0.000). The results for R = (0.994), R² = (0.989), F = (1607.390) and Durbin-Watson = (2.213) show that the regression model is highly predictive. Regression coefficients indicated negative effects from hybridization ratio (-0.357), mass fraction (-0.032), and fiber orientation (-0.017), all statistically significant (p = 0.000). Residual plots confirmed model validity. The TEM images of confirmation test sample 1 reveal fiber-matrix interfaces with particle sizes between (10.02–26.40 nm). Variations in scale (100 nm and 50 nm) show microstructural differences, suggesting strong adhesion, dispersion aggregation, and anisotropic behavior due to 90-degree fiber orientation within the epoxy matrix. The study concludes that strategic optimization of input parameters significantly enhances the impact resistance of hybrid biocomposites. The MISO framework proves effective for analyzing and predicting impact behavior, contributing to the design of durable, lightweight, and eco-efficient composite materials