Predicting the Tensile Properties of Automotive Steels at Intermediate Strain Rates via Interpretable Ensemble Machine Learning

Evaluating the dynamic impact properties of automotive steels is critical for structural design and material selection, but physical testing methods result in high costs and long lead times. In this study, a dataset was constructed by collecting data from high-speed tensile experiments on 65 automotive steels. Five machine learning models, including ridge regression, support vector machine regression, gradient boosted regression tree, random forest, and adaptive boosting regression, were developed to predict the yield strength (YS), ultimate tensile strength (UTS), and fracture elongation (FE) of automotive steels at 100/s using the composition, sample size, and quasi-static mechanical properties of automotive steels as input variables. To further improve the prediction accuracy, stacked ensemble ideas were used to integrate these single models. The results show that the ensemble model has higher prediction accuracy and generalization performance for mechanical properties at 100/s compared to a single model. When predicting the YS, UTS, and FE at 100/s, their 10-fold cross-validated average R2 are 0.913, 0.92, and 0.8, respectively. Most importantly, the Shapley additive explanation (SHAP)-based method reveals major features that significantly affect tensile properties at intermediate strain rates. The proposed methodology facilitates reductions in physical test requirements and costs.