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This article develops a hybrid model to analyse the dynamic interactions between a train, tracks and a bridge. The model couples the train and track subsystems to form an integrated time-dependent subsystem through a vertically interacting wheel–rail model. In turn, this time-dependent subsystem is coupled with the bridge subsystem by enforcing the compatibility of forces at the contact points between the track and the bridge. A new hybrid solution algorithm is proposed which combines the strongly coupled method and the loosely coupled method to numerically solve the equation of motion of the coupled train–track–bridge system in the time domain. The integrated time-dependent equation of motion of the train–track subsystem is solved by applying the strongly coupled method. The equilibrium equations of the train–track subsystem and bridge subsystem are then solved via the loosely coupled method using the Newmark integration scheme. Significantly faster convergence can be achieved by avoiding the iterative equilibrium calculations between the wheel and the rail, and the total computational efficiency increases significantly because of the considerably smaller size of the time-dependent equations of motion and larger integration time step. The accuracy and computational cost of the proposed method are validated and compared to the existing models using a case study on the vibration of a cable-stayed bridge.

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This article presents a low‐cost panoramic image stitching system for tunnel lining inspection. The system can produce a high‐quality layout panorama of the target lining using photographs taken freely in a tunnel with a hand‐held camera and the tunnel design information as inputs. The three‐dimensional (3D) freeform shape corresponding to the tunnel design geometry is used as the warping surface for photograph rectification. A newly designed random sample consensus algorithm is used to estimate the freeform tunnel shape from the 3D reconstructed point cloud, which can perform the registration between point sets with different sizes. These processes can make full use of the geometry information of a real tunnel and the reconstructed scene; thus, the photographs can be precisely rectified, and a planar motion stitching can composite them together. Two field applications demonstrate that the system can create a tunnel layout panorama with sufficient accuracy in tunnel lining inspection and that it is applicable to noncircular‐shaped tunnels.

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