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In this study, a multidisciplinary approach combining a numerical analysis in three dimensions and a laboratory test is developed to investigate the dynamic coupling effect as induced by vehicle–bridge interaction in the indirect measurement. To unveil such dynamic coupling and its influence on the frequency measurement, a single degree-of-freedom test vehicle is exclusively designed with adjustable frequency, which is a low-cost, easy-to-use, and reliable tool for measuring beam frequencies in the laboratory while providing valuable data for validating numerical models, calibrating sensors, and evaluating bridge performance. From the multidisciplinary analysis, the shifts of frequencies for both vehicle and bridge are consistently demonstrated as a result of vehicle–bridge interaction effect. Moreover, for the identification of higher-order bridge frequencies, the contact-point response works better than the vehicle’s response, even with shifted frequencies being observed in the three-dimensional numerical results. As an extension, a parametric study is conducted numerically to include various practical conditions, including different types and boundary conditions of a bridge as well as pavement irregularity.

Two higher-order analytical models based on a new higher-order theory for sandwich plates with flexible cores are developed considering the effect of the core material density and skin-to-core-stiffness-ratio (SCSR). The main difference between the two models is the role of the flexible core in the dynamic response of sandwich plates with cores of different stiffnesses. Firstly, the governing equations of a simply supported sandwich plate with a flexible core are derived based on the two models, and the analytical solutions are determined by using Navier’s approach. Then, the free vibration, static, dynamic bending and stress field characteristics of the sandwich plates with different SCSRs are investigated. The results obtained by the proposed method are compared with other published results. In particular, an accuracy assessment of the present dynamic models is conducted for different SCSRs. Finally, conclusions on the applicability of the proposed method and other theories on sandwich plates with different SCSRs are drawn.

Previously, the contact states between the bearing and journal of a spatial revolute joint (SRJ) with both axial and radial clearances were solved in the global coordinate system (GCS), which is complex and requires iterations. In this paper, a local-coordinate representation for the SRJs with clearance is combined with a vector-form particle-element method, i.e. finite particle method (FPM), to provide a more practical means for evaluation of the dynamic effects due to clearance. Firstly, the fundamentals of the FPM for analysis of spatial mechanisms are briefed. Then, a local-coordinate representation based on the revolution axis of the bearing is proposed. Specifically, the geometry of the journal and bearing is explicitly expressed using the coordinate transformation. The axial and radial contact states are evaluated by substituting the parametric equations and transforming them to quadratic and quartic equations, respectively, which can be analytically solved without iterations. The contact forces are evaluated in the local-coordinate representation and then transformed into the GCS representation. Two numerical examples, i.e. a spatial slider-crank mechanism and a spatial double pendulum, are provided to demonstrate the feasibility of the proposed method, by which the effects of joint-joint interaction and joint-flexible component interaction are fully discussed.

In this paper, an efficient and reliable method is developed for assessing the seismic performance of reinforced concrete (RC) frame structures by using the dynamic concentrated plastic beam–column element. Firstly, the beam–column element considering the dynamic effect caused by strain rate sensitivity of RC materials and the epistemic uncertainties in structural parameters is proposed, in which the mechanical behavior of plastic hinge is described by the damage index-based hysteretic model. Moreover, a simplified approach is employed to consider the strain rate-sensitivity of RC materials. Then the computation procedure for probabilistic seismic analysis of RC frame structures is illustrated based on the proposed element. The change in strain rate at each time step is considered by modifying the hysteretic model, which is further used in updating the matrices in dynamic equations. Finally, the probabilistic seismic response and damage analyses of a shaking table test RC frame structure are performed and the proposed method is validated with the experimental data. Furthermore, the influences of structural uncertainties on the analytical results of maximum drift ratio and collapse probability are discussed. It is indicated that both the dynamic effect and structural uncertainties need to be seriously taken into account for obtaining a more reliable seismic response and collapse assessment of RC frame structures.

Numerical simulation of tsunami is an effective method to reproduce what has occurred in the past and to predict future events for many tsunami-related research issues including warning systems. However, some real phenomena have not been fully integrated into numerical simulations for transoceanic tsunamis such as fault dynamics of rupture velocity, ocean currents, and the initial sea level. Considering the 2004 Indian Ocean tsunami event, this study evaluates the consequences of rupture velocity. Subsequently, numerical experiments were conducted to normalize the effects as represented by non-dimensional parameters. The rupture velocity, ocean current, and initial sea level were simplified to be uniform and common among simulations. Results of the experiment show that the sea depth along the propagation direction, distance from the tsunami source, rupture velocity, and initial sea level impart some considerable effects on a tsunami's arrival time and wave height. Nevertheless, ocean currents have almost no importance for the arrival time or wave height of oceanic propagation of tsunamis.