MPCA-based Domain Adaptation for Transfer Learning in Ultrasonic Guided Waves
This work addresses domain adaptation challenges in structural health monitoring for thin-walled structures, representing an incremental improvement with a statistically-based, data-efficient transfer learning framework.
The paper tackles the problem of data scarcity and limited generalization in ultrasonic guided wave-based structural health monitoring by proposing a novel transfer learning framework using Multilinear Principal Component Analysis (MPCA) for domain adaptation, achieving a substantial reduction in localization error compared to standard techniques across 12 case studies with different composite materials and sensor arrays.
Ultrasonic Guided Waves (UGWs) represent a promising diagnostic tool for Structural Health Monitoring (SHM) in thin-walled structures, and their integration with machine learning (ML) algorithms is increasingly being adopted to enable real-time monitoring capabilities. However, the large-scale deployment of UGW-based ML methods is constrained by data scarcity and limited generalisation across different materials and sensor configurations. To address these limitations, this work proposes a novel transfer learning (TL) framework based on Multilinear Principal Component Analysis (MPCA). First, a Convolutional Neural Network (CNN) for regression is trained to perform damage localisation for a plated structure. Then, MPCA and fine-tuning are combined to have the CNN work for a different plate. By jointly applying MPCA to the source and target domains, the method extracts shared latent features, enabling effective domain adaptation without requiring prior assumptions about dimensionality. Following MPCA, fine-tuning enables adapting the pre-trained CNN to a new domain without the need for a large training dataset. The proposed MPCA-based TL method was tested against 12 case studies involving different composite materials and sensor arrays. Statistical metrics were used to assess domains alignment both before and after MPCA, and the results demonstrate a substantial reduction in localisation error compared to standard TL techniques. Hence, the proposed approach emerges as a robust, data-efficient, and statistically based TL framework for UGW-based SHM.