Issue 75

A. Aabid et alii, Fracture and Structural Integrity, 75 (2025) 55-75; DOI: 10.3221/IGF-ESIS.75.06

(b) Mode II

(c) Mode III Figure 3: Confusion matrix for training and testing data for SVR

Random Forest In this case, the classification performance of the RF model across all modes for both training and testing datasets has been done, and the confusion matrix is shown in Fig. 4. Similar to the previous case, each mode of the RF model has been extracted based on the training and testing data. In Mode I, the training confusion matrix shows a dominant diagonal, particularly for the 5 mm and 20 mm classes, indicating that RF performs relatively well on those ends. However, in the testing matrix, significant misclassification is evident across all classes, especially between 10 mm and adjacent labels, suggesting weak generalization. For Mode II, the RF training matrix maintains strong diagonal values for 5 mm and 10 mm but misclassifies a few 15 mm and 20 mm samples. The test matrix shows high confusion, with nearly all crack length classes predicted incorrectly, highlighting the limited robustness under the shearing effects of this model. In Mode III, the RF shows severe training misclassifications concentrated in the 10 mm to 15 mm range. The test matrix is heavily scattered, with almost no consistent predictions, indicating that RF fails to adapt to the complex, out-of-plane fracture characteristics typical of Mode III. This confirms the RF model's declining reliability for Mode I and II.

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