Strain/Displacement Field Reconstruction and Load Identification of High-Speed Train Load-Bearing Structure Based on Linear Superposition Method

Real-time online reconstruction of strain/ displacement fields of critical load-bearing structures of high-speed trains (such as crossbeams and bogies) has been a challenging task because the complexity of load and geometry of load-bearing structures not only limits the layout of sensors but also affects the real-time structural 3-D reconstruction. In this article, a strain/displacement field reconstruction and load identification method based on linear superposition is proposed, and the strain and displacement fields are reconstructed according to the strain thresholds that can be updated in real time using the experimental strains obtained from fiber Bragg grating (FBG) sensors and simulated strains stored offline. The proposed method of reconstruction is numerically validated through the finite-element analysis, the effect of sensor location and number on reconstruction error is analyzed, and the balance between the number of sensors and reconstruction efficiency is discussed from the perspective of computational time. Besides, the method is experimentally evaluated on an aluminum alloy crossbeam, while the strain and deformation of the crossbeam under load are reconstructed in real time. Moreover, the magnitude and location of load are identified using strain thresholds on the structure to demonstrate the effectiveness and real-time performance of the reconstruction method in practice.