Engineering with Computers最新文献

We present a high-performance coupled framework that advances the integration of the finite volume method (FVM) and the lattice Boltzmann method (LBM) for multi-physics thermal flow simulations, including heat conduction, conjugated heat transfer, natural and forced convection, and phase change. The proposed scheme employs a central-moments-based collision operator for both velocity and temperature fields, substantially improving numerical stability and accuracy over traditional approaches within the LBM community. The reconstruction strategy, combining regularised and high-order truncated equilibrium methods, ensures smooth and accurate data exchange at FVM-LBM coupling interfaces. The implementation employs the Parallel Location and Exchange coupling library, enabling efficient and scalable communication between the FVM and LBM. Validation against standard benchmark problems and complex melting scenarios demonstrates excellent numerical accuracy and convergence. These algorithmic advances establish the proposed framework as a significant step forward in coupled FVM-LBM methods for multiscale thermal flow problems.

This paper presents two performance optimization techniques for a mesh adaptation method that is designed to help streamline the discretization of complex vascular geometries within the numerical modeling process. This method is integrated into a pipeline with an image-to-mesh conversion tool to generate adaptive anisotropic meshes from segmented medical images. The pipeline is shown to satisfy quality, fidelity, smoothness, and robustness requirements while providing near real-time performance for medical image-to-mesh conversion. Tested with two brain aneurysm cases and utilizing up to 96 CPU cores within a single, multicore node on Purdue University's Anvil supercomputer, the parallel adaptive anisotropic meshing method utilizes a hierarchical load balancing model (designed for large, cc-NUMA shared memory architectures) and contains an optimized local reconnection operation that performs three times faster than its original implementation from previous studies. While utilizing a new user-defined sizing function, we also show an adaptive isotropic method that generates meshes with good quality and fidelity of up to approximately 50 million elements in less than a minute while the adaptive anisotropic method is shown to generate approximately the same number of elements in about 5 min.

Differential equation-driven evolution strategies are often associated with boundary-driven topology optimization methods, such as the level set method. However, differential equations can also be utilized effectively in density-based approaches. This paper presents a design update scheme formulated using differential equations to evolve elemental densities in topology optimization. The proposed scheme transforms the differential equation into an absolute increment format, closely related to the optimality criteria (OC) method, which is traditionally implemented in a relative increment format in density-based methods. The relative increment format of the OC method typically ensures an efficient and stable optimization process, whereas the absolute increment format tends to enable a more active and responsive optimization process, potentially leading to optimized results with improved performance. Furthermore, the absolute increment format can be converted into a relative one if needed. This study explores compliance minimization problems for both isotropic composite and single-material cases. Detailed MATLAB implementations for these cases are presented and thoroughly explained. Numerical examples demonstrate that the differential equation-driven update scheme effectively addresses density distribution optimization problems, offering an alternative to classical density methods.

This paper presents spline-based coupling methods for partitioned multiphysics simulations, specifically designed for isogeometric analysis (IGA) based solvers. Traditional vertex-based coupling approaches face significant challenges when applied to IGA solvers, including geometric accuracy issues, interpolation errors, and substantial communication overhead. The methodology draws on the IGA mathematical framework to deliver coupling solutions that preserve the high-order continuity and exact geometric representation of splines. We develop two complementary strategies: (1) a spline-vertex coupling method that enables efficient interaction between IGA and conventional solvers, and (2) a fully isogeometric coupling approach that maximizes accuracy for IGA-to-IGA communication. Both theoretical analysis and extensive numerical experiments demonstrate that our spline-based methods significantly reduce communication overhead compared to traditional approaches while simultaneously enhancing geometric accuracy through exact boundary representation and maintaining higher-order solution continuity across the coupled interfaces. We quantitatively confirm the communication efficiency benefits through systematic measurements of both transfer times and data volumes across various mesh refinement levels, with experimental results closely aligning with our theoretical predictions. Our benchmark studies further demonstrate the geometric fidelity advantages through exact boundary representation, while also highlighting how the inherent mathematical structure of splines naturally preserves solution derivatives across interfaces without requiring additional computation or specialized transfer algorithms. This work not only provides efficient coupling strategies tailored to IGA-based solvers but also establishes a practical bridge between IGA and traditional discretization methods in partitioned multiphysics simulations. By offering viable options for coupling conventional solvers with IGA-based components, our approach enables broader adoption of IGA in established simulation workflows while ensuring accurate and high-performance interface communications.

Numerical modelling of structural self-contact and crack propagation presents significant challenges due to the inherently discontinuous and non-differentiable nature of the underlying physical phenomena. Traditional contact models demand explicit definition and tracking of contact points, while fracture models often rely on predefined crack initiation sites, sharp interfaces, and re-meshing. This study introduces a novel framework that overcomes these limitations within a unified and numerically stable variational formulation. The contact phenomenon is described through the hyperelastic third medium contact model and fracture is represented by a phase field. Structures are embedded in a third medium that stiffens under compression, enabling the transfer of forces between structural members. Crack propagation occurs in regions in which it is energetically favourable for the system to evolve toward a fully damaged state, specifically where the critical energy release rate is exceeded. Careful treatment is required when coupling the two phenomena, particularly concerning the void material behaviour. This work presents an efficient and differentiable numerical model that captures both nonlinear phenomena within a unified framework. This framework will allow designers and engineers to efficiently analyse complex nonlinear structural behaviours, previously requiring separate models that involved pre-defined crack initiation sites and contact points. Lastly, the differentiable nature of the model facilitates straightforward future integration into topology optimisation pipelines, providing designers the ability to intentionally design for and leverage self-contact interactions and material failure as functional, performance-enhancing features.

Understanding the mechanical behaviour of defective materials is key to predicting failure and enhancing performance. Traditional fracture mechanics often requires assumptions about geometry and loading that are unavailable in experimental systems. We present a MATLAB-based computational toolbox that extracts configurational forces and mixed-mode SIFs directly from experimentally measured displacement or deformation gradient fields, like digital image/volume correlation and high (angular) resolution electron backscatter diffraction. The toolbox implements path-independent energy integrals, including the J- and M-integrals, and introduces a novel mode decomposition formulation that isolates mode I-III SIFs contributions without predefined specimen geometries, applied loads, or boundary conditions. Applications to microcracks, dislocations, and fatigue cracks demonstrate its robust, geometry-independent characterisation, which can enable data-driven analysis of defect behaviour in anisotropic and complex materials. The framework is material-agnostic in principle and operates directly on experimental fields; however, its current implementation assumes small-strain kinematics, making it most applicable to linear and anisotropic elastic and elastoplastic materials such as metals and ceramics.

Supplementary information: The online version contains supplementary material available at 10.1007/s00366-025-02262-5.

Weak imposition of essential boundary conditions (i.e., weak BCs) for the Navier-Stokes equations of incompressible flows allows a certain amount of controlled numerical flow slip on the solid surface. Numerical flow slip mimics the presence of a thin boundary layer that would otherwise need to be captured using a fine mesh resolution. As a result, weak BCs enable the use of coarser meshes near solid walls without sacrificing numerical solution accuracy, which significantly reduces the computational costs, especially for 3D, wall-bounded turbulent flows. However, weak BCs for compressible flows are not as well understood as those for the incompressible-flow case. In particular, numerical instabilities were observed in some cases where the weak BCs were simultaneously imposed for the velocity and temperature fields. In the present effort, to address these stability issues, we develop a methodology for the design of compressible-flow weak BC operators and demonstrate the improved performance of the resulting weak BC formulations using challenging 2D and 3D test cases.

Many engineering challenges involve optimising multiple criteria that often represent conflicting targets, posing significant difficulties for standard methods like gradient-based algorithms. This complexity is especially important in the context of acoustic wave propagation, where noise barriers are designed to attenuate sound pressure level (SPL). Achieving optimal performance requires carefully balancing design factors such as shape and material selection with economic constraints, making the optimisation process both technically demanding and computationally intensive. This paper proposes the development of a noise prediction surrogate model for the multi-objective optimisation of acoustic barriers. This model is developed based on data set generated employing a two-dimensional singular boundary method. The optimisation process is conducted using a multi-objective Bayesian optimisation algorithm, which is applied to the problem of acoustic line source diffraction in the presence of a porous noise barrier. Two distinct barrier configurations are considered: a straight-walled barrier and a T-shaped barrier. With a view to reduce the SPL behind the noise barrier, the set of spanned parameters includes the SPL on the side of the barrier opposite to the source, barrier's height, cap length of T-shaped barrier, porosity, tortuosity, and airflow resistivity of the material, integrating both microstructural and macrostructural aspects into the optimisation. Surface impedance boundary condition is used in the model to represent the dissipation at the surface of the noise barrier. The results demonstrate that the proposed optimisation framework enables efficient exploration of trade-offs to achieve an optimal barrier design that balances acoustic performance, material cost, and shape constraints.

Magnetic Resonance Imaging (MRI) scanners employ superconducting magnets to produce a strong uniform magnetic field over the bore of the scanner as part of the imaging process. Superconductors are preferred, as they can generate the required field strengths without electrical resistance, but, to do this, the materials need to be cooled to very low temperatures, typically around 4.2 K. However, due to imperfections in the windings, cracks and small air gaps in the epoxy resin between the wires, heating can occur leading to a process known as magnet quench. During magnet quench, the magnet temperature rises quickly, and the magnet loses its superconductivity. This work presents an accurate numerical model for predicting magnet quench for axisymmetric MRI scanners by solving the coupled system of thermal, electromagnetic and circuit equations by means of a high order/hp-version finite element method where regions of high gradients are resolved with boundary layer elements. A series of numerical results are included to demonstrate the effectiveness of the approach.

A generic side mirror can be approximated to the combination of a half cylinder topped with a quarter of sphere. The flow structure in the wake of the side mirror is highly transient and the turbulence plays an important role affecting aeroacoustics through pressure fluctuation. Thus, this geometry is one of the test cases object of several numerical studies in recent years to assess the aerodynamic and aeroacoustic capabilities of the turbulence models. In this context, this study presents how the second-generation URANS closure STRUCT-(epsilon ) is able to properly predict the expected stagnation, flow separation and vortex shedding phenomena. Besides, the predictive accuracy for the noise generation mechanism is evaluated by comparing the spectra of the sound pressure level measured at several static pressure sensors with the numerical results obtained with the STRUCT-(epsilon ). The response of this turbulence model has exceeded that from other hybrid methods and is in good agreement with the results from Large-Eddy Simulations or the experiments. To conclude the paper, the applicability of STRUCT-(epsilon ) to construct a Spectral Proper Orthogonal Decomposition method that helps identifying the most energetic modes to appropriately capture the dominant flow structures is also introduced.