Research on ultra-wideband Terahertz transmission lines based on silicon photonic crystals

Transient magnetohydrodynamic flow over a rotating vertical porous surface incorporating thermal radiation, hall and ion-slip effects: Using finite element method

Optimization of the effectiveness of lower canine retraction: A FEM comparison of different attachment systems with no attachments in clear aligners.

Accurate thermal field prediction is the cornerstone of thermal design of high-frequency transformer (HFT). The leakage flux induced power loss (LFPL), which includes leakage flux eddy current loss (LFECL) and leakage flux core loss (LFCL), can increase the hotspot temperature of nanocrystalline core HFT. This paper proposes a coupled thermal field prediction method for nanocrystalline core HFT considering LFPL and analyzes the thermal field characteristics. Firstly, the LFPL density distributions in nanocrystalline core are analyzed with finite element method, demonstrating high LFPL density on surface ribbons. Then, a coupled thermal field prediction method for nanocrystalline core HFT considering LFPL is proposed. The total thermal field is calculated by summation of thermal fields with LFECL, LFCL, and main flux core loss and winding loss. The thermal fields with LFPL are calculated with unidirectional magnetic-thermal coupled method, in which LFPL densities are calculated by proposed equivalent frequency domain simulation method and coupled to Heat Transfer module. The temperature dependences of power losses are considered for high-accuracy thermal field prediction. With the proposed method, the temperature calculation errors are reduced to below 3°C. Finally, the thermal field characteristics are analyzed. Finite element simulation results show that hotspot temperatures will be greatly increased by LFPL. The proposed method can help improve the thermal design of nanocrystalline core HFT.

Three-dimensional site characterization for unsaturated soil nail wall analysis using integration of multivariate co-kriging and finite element method

An efficient strong seismic analysis model for running safety thresholds of train-track-high pier bridge dynamic system

• Numerical evaluation is performed on an Archimedean spiral shaped circular piped heat exchanger. • More spiral turns resulted in higher Dean Number ( De ) with the generation of significant secondary flow offsetting the adverse pressure gradient effects. • The h and the Nu increased by almost 20% and 30%, respectively, by the combined effects of spiral turns and nanoparticle. • The spiral configuration provides ∼ 8.2 times more heat transfer surface area per unit footprint length than the linear exchanger. This research investigates the thermal-hydraulic characteristics of an Archimedean spiral shaped circular piped heat exchanger with different number of turns ( N ) using ZnO/water nanofluids using finite element method. Conventional heat transfer fluids and straight-tube geometries face limitations due to low thermal conductivity and inefficient flow patterns. To address this, we explore the synergistic effect of geometric modification and nanofluid enhancement. The simulation model solves fluid flow and heat transfer equations under non-isothermal conditions for linear and spiral models with different N across a laminar flow regime with Reynolds number ( Re ) varying from 350 to 650. The results demonstrate that the spiral geometry induces secondary flows (Dean vortices), whose strength, quantified by the Dean number ( De ), increases with the N due to a decreasing radius of curvature. This improves fluid mixing, thins the thermal boundary layer, and improves the heat transfer rate than linear ones. More turns resulted in smaller radii of curvature (tighter spiral) and the Dean Number ( De) reached ∼ 70 for N = 2 and as high as ∼ 130 for N = 5 at Re = 650, showing the generation of secondary flow. Overall, the heat transfer coefficient ( h ) and Nusselt Number ( Nu ) improved by almost 20% and 30%, respectively, indicating that both change in heat exchanger geometry and nanoparticle concentration significantly affected the thermal performance, leading to substantial improvements in heat transfer rates. The performance evaluation criterion (PEC) reached ∼3.95, confirming the design's superiority offsetting the adverse pressure gradient effects. The spiral configuration provided more heat transfer surface part per unit footprint length than the linear exchanger and thus suitable for compact footprint thermal applications.

The solidification of volcanic rock-like materials using cohesive zone models and finite element method

The biomechanical effects of different materials on the application of femoral external fixator: Stainless steel versus titanium alloy and healthy versus osteoporosis bone properties.

An uncoupled scheme for predicting the dynamic mooring tension based on the finite element method and artificial neural networks

Shape morphing, widely required in aerospace and aeronautical structures, utilizes embedded actuators to regulate shape changes. From a structural design perspective, the objective is to minimize the discrepancy between target and achieved displacements at certain degrees-of-freedom (DOF). This work introduces a shape control problem that considers full-field (all-DOF) displacement matching, and investigates mesoscale topology optimization of cellular lattice structures for this problem. The proposed approach models lattice structures with uniform mesostructures using a two-scale homogenization-based finite element method (FEM) and solves the optimization problem with an extended Moving Iso-surface Threshold (MIST) framework. Numerical examples are investigated for design cases considering typical desired morphing shapes in engineering practice and shapes not achievable for natural isotropic material to demonstrate the effectiveness and efficiency of the proposed method: a near-zero shear modulus mesostructure is obtained for pure shear deformation; a near-zero Poisson’s ratio design is achieved for one-dimensional extension; and a maximum shear modulus configuration is realized for trailing edge morphing, where the shape errors are 1.02%, 5.36% and 6.35% respectively. Furthermore, full-scale finite element analysis validates the performance of the optimized mesostructures, confirming the efficacy of the overall design and modeling framework. • Propose shape control problem considering full-field (all-DOF) displacement matching • Model lattice structures via two-scale homogenization-based finite element method • Moving Iso-surface Threshold (MIST) framework to solve mesostructure design problem • Achieve desired morphing shapes not attainable with natural isotropic materials

Hybrid-controlled induction heating for ammonium bisulfate removal in power plant air preheaters

This paper presents a winding model for predicting winding losses in planar inductors. In transformer windings, the magnetic field can often be simplified to a one-dimensional problem, as the net current flowing into the core window is nearly zero. However, this simplification is not applicable to inductors, where two-dimensional (2D) magnetic fields are always present. The 2D field arises from two primary sources: the non-zero total current flowing into the core window and the fringing field around air gaps. Consequently, a 2D modeling approach is essential for accurate inductor analysis. Existing methods are often computationally intensive or simplified for a specific situation; this work aims to provide a method that balances accuracy and computational speed. This paper proposes an easily applicable 2D numerical method, based on Green's function and Gaussian quadrature, to solve the quasi-static magnetic field problems in planar windings. Various quadrature methods are compared, leading to the selection of Lobatto quadrature for this application. The proposed 2D numerical method is then incorporated into a winding model to construct the impedance matrix for planar windings. This comprehensive model can calculate losses resulting from non-uniform 2D magnetic fields on foil windings and accounts for current sharing among parallel conductors. The method is validated through comparisons with 2D finite element method (FEM) simulations and measurements performed on a planar inductor with parallel windings.

Finite element analysis of transnasal, zygomatic and pterygoid implants in the rehabilitation of the atrophic maxilla.

A global-local two-level inverse finite element method for structural local displacement field reconstruction under non-simple boundary conditions

• A simple and low-cost piezoelectric vector hydrophone is reported. • This device uses a piezoelectric circular plate with different clamped conditions. • Simulation models and experimental results of vector hydrophones are presented. • The design of the hydrophone facilities its application in marine environments. • This hydrophone can be used to detect hydroacoustic signals in marine ecosystems. Vector hydrophones enable the acquisition of underwater acoustic signals for monitoring aquatic fauna and supporting marine ecosystem protection. However, conventional underwater acoustic technologies often involve complex structural designs, challenging component integration, high fabrication costs, and demanding signal-processing requirements, which limit their cost-effectiveness. To address these challenges, we propose a low-cost and simple vector hydrophone based on a piezoelectric diaphragm structure of commercial lead zirconate titanate (PZT) film. The hydrophone design enables the easy integration of its main components, simplifying the measurement system for underwater acoustic signals. In addition, the proposed hydrophone features a simple piezoelectric cantilever structure, enabling its use and portability in various marine scenarios. The resonance frequencies and directivity patterns of the hydrophone structure are modeled using finite element method simulations. Also, the hydrophone performance is measured within a calibration tank.. The fabricated hydrophone exhibits a resonant frequency near 8 kHz and a sensitivity of −200 dB (re 1 V/µPa), together with a well-defined figure-of-eight directivity pattern. The dipole directivity pattern of the hydrophone at resonance achieves 22 dB difference between normal and perpendicular sound incidence. Thus, the reported vector hydrophone has potential applications for underwater acoustic signal sensing in marine ecosystems, without requiring sophisticated and expensive components.

Optimal convergence analysis of arbitrary Lagrangian–Eulerian finite element methods in energy norm for Poisson–Nernst–Planck moving boundary problems

A comprehensive analysis on obstacle-driven flow reconfiguration inclined MHD thermo-bioconvection: A porous cavity study with Galerkin finite element method and XGBoost machine learning surrogates

Advances and adoptions of digital technology and computer simulation in engineering are driving the development of fully-automated methods for engineering analysis. The paper reviews the scaled boundary finite element method (SBFEM) and its salient features as a general-purpose tool for modern computational engineering. Emphasis is placed on its capacity on achieving a fully-automated framework suitable to high-performance computing. In the SBFEM, an element is constructed semi-analytically. The boundary of the element is discretized and the solution in the radial direction is obtained from the solution of ordinary differential equations. The SBFEM formulation can easily satisfy radiation boundary conditions and model stress singularities accurately using its analytical feature. Furthermore, it supports arbitrary polygonal and polyhedral elements. Recent advances have focused on integrating SBFEM with fully automated mesh generation techniques, such as octree and quadtree algorithms, enabling seamless workflows from multiple geometric modeling formats (e.g., digital images, point clouds, and CAD data) to computational analysis. This automation facilitates applications in dynamic response analysis, fracture mechanics, inverse problems, topology optimization, and high-performance computing.

Dirac cones and topological torsional modes in phononic nanowires using Su-Schrieffer-Heeger Model.