The primary objective of this article is to present a semi-analytical algorithm for the transient behaviors of Functionally Graded Materials plates (FGM plates) considering both the influence of in-plane displacements and the influence of temperature changes. Based on the classical plate theory considering the effect of in-plane displacements, the equilibrium equations of the motion system are derived by Hamilton’s principle. Here, we propose a novel, accurate, and efficient semi-analytical method that incorporates the Fourier series expansion, the Laplace transforms, and its numerical inversion and the Differential Quadrature Method (DQM) to simulate the transient behaviors. This paper validates the proposed method by comparisons with semi-analytical natural frequency results and those from the literature. Expressly, the results of dynamic response also agree well with those generated by the Navier’s method and Finite Element Method (FEM). A convergence study that utilizes the different numbers of sampling points shows that the process can converge quickly, and a few sampling points can achieve high accuracy. The effects of various boundary conditions at the ends, material graded index, and temperature change are further investigated. From the detailed parametric study, it is seen that the peak displacement increases as the edge degrees of freedom, the gradient index of the material, and temperature change increase.

This study Fills a vital gap in the simulation assessment of underwater acoustic target strength, where existing methods fail to account for bidirectional uncertainties originating from both simulation and experimental sources. This paper introduces a novel method for Evaluation of Simulation Model Confidence based on Bidirectional Uncertainty Assessment (ESMC-BUA), optimized through an orthogonal design approach. The methodology progresses through four phases:(1) Construction of a multiphysics simulation model with uncertainty source identification; (2) Orthogonal design-driven optimization of critical parameters considering interaction effects; (3) Experimental uncertainty quantification; (4) Credibility evaluation through normalized overlap analysis of simulation-experimental uncertainty bounds. Results indicate the method quantifies simulation reliability under limited experimental data, with orthogonal design optimizing critical parameters to achieve a 'Good' confidence level of 80.4% in the validation case. This method not only addresses a gap in underwater acoustic characterization but also demonstrates application potential in areas such as stealth material development and sonar system optimization, offering a methodological advancement for the design and evaluation of underwater acoustic systems.

Against the backdrop of global climate change and rapid urbanization, island cities face increasing compound-flood risks due to their fragmented topography and limited terrestrial space, yet cross-scale modeling and high-resolution exposure assessment for archipelagic environments remain insufficient. Taking Zhoushan City, China, as a case study, this research develops an integrated compound-flood multi-receptor exposure assessment framework combining cross-scale hydrodynamic modeling with high-resolution spatialization. For hazard assessment, a one-way sequential coupling of a parametric typhoon model, FVCOM, and LISFLOOD-FP was employed to simulate storm-surge, pluvial, and compound flooding at 50-, 200-, and 1000-year design levels. Model performance was evaluated using tidal-gauge observations, historical storm-surge records, remotely sensed historical inundation, and documented urban waterlogging locations. For exposure assessment, Random Forest-based dasymetric mapping was used to generate 30 m population and secondary- and tertiary-sector GDP datasets; primary-sector GDP was spatialized using a land-cover-based approach, and 3314 critical-infrastructure facilities were compiled across eight subsystems. The results reveal the following: (1) compound-flood inundation areas were 289.95, 424.93, and 513.31 km² under the 50-, 200-, and 1000-year design scenarios, respectively; (2) under the 1000-year compound scenario, 57.5% of the population, 51.3% of GDP, and 63.3% of critical infrastructure were exposed; (3) infrastructure exposure showed strong subsystem heterogeneity, with coastal facilities having the highest exposure ratio (76%) and emergency-rescue facilities reaching 65.3%; (4) sector-disaggregated GDP exposure revealed substantial economic-geographic differences among districts/counties, highlighting the need for differentiated adaptation strategies. The proposed framework provides spatially explicit information to support differentiated coastal adaptation planning and is transferable to other archipelagos and small island cities with similar data constraints.

Reciprocity calibration of hydrophones in a bounded water tank is biased by boundary reflections that prevent free-field conditions. A method combining complex analytic signals with physically adaptive coherent smoothing is proposed to recover the free-field sensitivity. Sine and cosine linear sweeps are transmitted in a V-shaped (down/up) sequence; the complex analytic signal is mapped into the frequency domain to remove the time–frequency ambiguity. The smoothing window width is set from the geometry of the shortest reflection path in the tank, and the transfer impedance is smoothed by a three-stage cascaded complex moving weighted average (CMWA). A mirror-source correction factor compensates for the deterministic first-order reflections, and a modal coherence enhancement factor corrects the low-frequency bias where the tank modes are sparse and CMWA's incoherent-superposition assumption fails. The equivalent absorption coefficient αeq(f) of the tank is obtained by simulating the frequency-dependent reflection coefficient of the anechoic wedges, anchoring the enhancement factor to measurable physical quantities. The uncertainty is evaluated following the GUM from sensitivity coefficients derived from the measurement model. Dual-tank experiments (small research tank, large verification tank) over 1 kHz–10 kHz show a maximum deviation of 0.67 dB from single-frequency calibrations on a free-field standard device (at 6.3 kHz) and an inter-tank deviation below 1 dB. The combined standard uncertainty is 0.40 dB–0.45 dB, the expanded uncertainty (k = 2) is 0.81 dB–0.90 dB, and the results agree with the standard device within its stated uncertainty, confirming the feasibility of reciprocity calibration in bounded water tanks.