Chung-Yue Wang

This study presents a new formulation for laminated composite thick shells by incorporating the discrete Kirchhoff–Mindlin triangular (DKMT) element into the vector form intrinsic finite element (VFIFE) method. This integration enables the accurate modeling of transverse shear effects, which are difficult to capture using conventional VFIFEs. In this framework, the shell is discretized into particles whose motions are analyzed over discrete time intervals, referred to as path elements. Euler’s law of motion governs particle dynamics, while triangular elements connect the particles and describe local deformation and internal forces. Quaternions represent rigid body rotations within the convected material frame, and internal forces are obtained from the shape functions of the VFIFE–DKMT element. The formulation is validated through numerical examples involving geometrically nonlinear displacements, dynamic responses, and large deformations in isotropic and composite shells. The results demonstrate the accuracy and robustness of the proposed method in predicting the nonlinear motion of thick shell structures.

This study presents a three-dimensional numerical model with the novel rigid fluid method (RFM) to simulate slide-type landslides. RFM, coupled with the Navier–Stokes solver Splash3D, is developed to calculate the movement and rotation of a moving solid. With the pressure and shear stress data in each grid collected by the discrete element method, the moving solid is granted to be involved in the simulation. The model is validated against a three-dimensional experiment of a sphere entering water, demonstrating good agreement in terms of displacement and air column pinch-off time. Subsequently, the model is applied to simulate the process of a semispherical landslide tsunami, using a semispherical laboratory experiment as a benchmark. The numerical results show excellent agreement with the experimental data in terms of sliding track, velocity, dynamic pressure, and wave height. To investigate the applicability of the model to real-world scale events, the above-mentioned case is scaled up proportionally, and the time, flow velocity, dynamic pressure, and resultant force are compared to verify the Froude number similarity. The results indicate that the model can effectively capture the essential features of landslide-induce tsunamis and has the potential to be used for further studies on the impacts of such events.

This paper studies elastic stress wave propagation generated by an impact in a system consisting of a moving striker rod and an initially stationary semi-infinite rod. This research emphasizes the role of different general impedances in affecting the response during the wave propagation process. The Rayleigh–Love rod theory is used in this research to consider lateral inertia and Poisson’s effects on longitudinal waves in rods, as these factors lead to greater stress results compared to the traditional wave equation. To solve the complex wave equations in a Rayleigh–Love rod with different general impedances, the numerical inversion of Laplace transformation is applied and verified using the results of previous research. This study demonstrates that variations in general impedances cause different wave reflection and transmission behaviors at the interface. As the wave interacts with this discontinuity of impedance, it may be amplified or attenuated, and changes in impedance can significantly affect wave propagation behaviors.

This paper presents an in-depth study of the stress wave behavior propagating in a Rayleigh–Love rod with sudden cross-sectional area variations. The analytical solutions of stress waves are derived for the reflection and transmission propagation behavior at the interface of the cross-sectional area change in the rod, considering inertia and Poisson’s effects on the rod material. Examples solved using the finite element method are provided to verify the correctness of the analytical results. Based on the forward analysis of Rayleigh–Love wave propagation in a rod impacted by a striker rod, an impact-echo-type nondestructive testing (NDT) method is proposed to conduct defect assessment in rod-type structural components with sudden cross-sectional area changes within a cover medium. This proposed NDT method can identify the location, extension, and cross-sectional area drop ratios of an irregular zone in the rod to be inspected.

This paper presents an in-depth study of the stress wave behavior propagating in a Rayleigh–Love rod with a sudden cross-sectional area change. The analytical solutions of stress waves are derived for the reflection and transmission propagation behavior at the interface of the cross-sectional area change in the rod, considering inertia and Poisson’s effects. Examples solved by the finite element method are provided to verify the correctness of the analytical results. In addition to the forward analysis of Rayleigh–Love wave propagation in rods impacted by a striker rod, a nondestructive testing method is proposed to conduct the defect assessment in the rod type of the structure component with a sudden cross-sectional area change within a cover medium by using the measured signals at the measurable zone of the rod to be inspected.

Bridges are essential components of transportation networks and play a crucial role in the operation of our infrastructures. As a result, inspecting, maintainin Bridges are essential components of transportation networks and play a crucial role in the operation of our infrastructures. As a result, inspecting, maintainin

The determination of existing cable forces is essential for evaluating the performance of bridges. The vibration technique is preferred among available practical methods because it is simple, fast, and economical. To apply this method, many researchers introduced analytical and empirical formulas considering bending rigidity, cable length, and boundary conditions. Nevertheless, most existing procedures to determine cable forces are for single cables, which are unsuitable for cable networks. To measure the cable forces of the cable networks, engineers should remove any cross-ties before conducting field tests. However, the removal of cross-ties separates the cable network into two independent cables, which does not reflect the actual behavior of the cable network. Hence, to save time and improve accuracy, this paper introduces a method to directly identify the cable tensions of a two-cable network without removing any cross-ties. This technique can precisely estimate the cable forces of the two-bending cable networks with arbitrary boundary conditions with an error of less than 1.0 percent.

A two-phase ultrasonic velocity tomography technique was introduced to inspect the concrete quality of bridge pylons in Taiwan. In phase I, the modified cross-hole sonic logging method was applied to rapidly identify the aberrant sections of pylon shafts and horizontal beams. Most of the concrete quality was classified as good (G), ie the apparent P-wave velocity ranged from 3600 m/s to 4300 m/s. In phase II, the cross-sectional velocity image method examined the sections with possible anomalies and, in contrast, the uniform sections of the pylon shafts. The cross-sectional velocity image approach effectively demonstrated the spatial position and range of anomalies in the pylon shaft cross-sections. It was suggested that the relatively low-velocity zones, confirmed with surface concrete spalling, be listed as future repair targets for the bridge agency.

A computationally efficient method is proposed for analyzing train and bridge dynamic interaction responses based on the vector form intrinsic finite-element method. The proposed method does not need to establish a large number of complicated dynamic coupling equations for the train and bridge, in contrast to the traditional finite-element method. A train with multiple cars traveling over a railway bridge with multiple spans was analyzed, and two computational models were considered: two-axle and coach models. The effects of rail irregularity and rail ballast were also considered. In the proposed method, the bridge is modeled as mass particles linked by a series of massless beam elements, and the train is simulated by mass particles. The motions of the mass particles are governed by Newton’s second law, and the central difference scheme is employed to solve the equation of motion for each mass particle. The fictitious reverse-motion procedure is employed to obtain the pure deformations of the massless beam elements, from which the internal forces exerted on the mass particles are evaluated. Assembly of the global stiffness matrix is avoided, and each mass-particle motion is calculated independently, which makes the proposed method easy and efficient. Compared with existing analytical and numerical methods, the proposed method provides simpler modeling of the dynamic interaction between the train and bridge and more efficient computation. Furthermore, the proposed method can yield very accurate results.