Search Results (294)

Modeling and simulation of aneurysm formation, growth, and rupture plays an essential role in a wide spectrum of application scenarios, ranging from risk stratification to stability prediction, and from clinical decision-making to treatment innovation. Unfortunately, it remains a non-trivial task due to the difficulties imposed by the complex and under-researched pathophysiological mechanisms behind the different development stages of various aneurysms. In this paper, we present a novel computational method for aneurysm simulation using smoothed particle hydrodynamics (SPH). Firstly, we consider blood in a vessel as a kind of incompressible fluid and model its flow dynamics using the SPH method; and then, to simulate aneurysm growth and rupture, the relationship between the aneurysm development and the properties of fluid particles is established by solving the motion control equation. In view of the prevalence of aneurysms in bifurcation vessels, we further enhance the capability of the model by introducing a solution for bifurcation aneurysms simulation according to Murray’s law. In addition, a CUDA parallel computing scheme is also designed to speed up the simulation process. To evaluate the performance of the proposed method, we conduct extensive experiments with different physical parameters associated with morphological characteristics of an aneurysm. The experimental results demonstrate the effectiveness and efficiency of proposed method in modeling and simulating aneurysm formation, growth, and rupture. Full article

Various nature-based solutions (NbS)—such as constructed wetlands, drainage ditches, and vegetated buffer strips—have recently demonstrated strong potential for mitigating pollutant transport in open channels and river systems. Numerical modeling is a widely adopted and effective approach for assessing the performance of these interventions. This study presents the first development of a two-dimensional (2D) meshless advection–diffusion model based on an Eulerian smoothed particle hydrodynamics (SPH) framework, specifically designed to simulate passive pollutant transport in open channel flows. The proposed model marks a pioneering application of the ESPH technique to environmental pollutant transport problems. It couples the 2D depth-averaged shallow water equations with an advection–diffusion equation to represent both fluid motion and pollutant concentration dynamics. A uniform particle arrangement ensures that each fluid particle interacts symmetrically with eight neighboring particles for flux computation. To represent the pollutant transport process, the dispersion coefficient is defined as the sum of molecular and turbulent diffusion components. The turbulent diffusion coefficient is calculated using a prescribed turbulent Schmidt number and the eddy viscosity obtained from a Smagorinsky-type mixing-length turbulence model. Three analytical case studies, including one-dimensional transcritical open channel flow, 2D isotropic and anisotropic diffusion in still water, and advection–diffusion in a 2D uniform flow, are employed to verify the model’s accuracy and convergence. The model demonstrates first-order convergence, with relative root mean square errors (RRMSEs) of approximately 0.2% for water depth and velocity, and 0.1–0.5% for concentration. Additionally, the model is applied to a laboratory experiment involving 2D pollutant dispersion in a 90° junction channel. The simulated results show good agreement with measured velocity and concentration distributions. These findings indicate that the developed model is a reliable and effective tool for evaluating the performance of NbS in mitigating pollutant transport in open channels and river systems. Full article

Abrasive waterjet technology is a promising sustainable and green technology for cutting underground structures. Abrasive waterjet usage in demolition promotes sustainable and green construction practices by reduction of noise, dust, secondary waste, and disturbances to the surrounding infrastructure. In this study, a numerical framework based on a coupled Smoothed Particle Hydrodynamics (SPH)–Finite Element Method (FEM) algorithm incorporating the Riedel–Hiermaier–Thoma (RHT) constitutive model is proposed to investigate the damage mechanism of concrete subjected to abrasive waterjet. Numerical simulation results show a stratified damage observation in the concrete, consisting of a crushing zone (plastic damage), crack formation zone (plastic and brittle damage), and crack propagation zone (brittle damage). Furthermore, concrete undergoes plastic failure when the shear stress on an element exceeds 5 MPa. Brittle failure due to tensile stress occurs only when both the maximum principal stress (σ₁) and the minimum principal stress (σ₃) are greater than zero at the same time. The damage degree ($\chi$) of the concrete is observed to increase with jet diameter, concentration of abrasive particles, and velocity of jet. A series of orthogonal tests are performed to analyze the influence of velocity of jet, concentration of abrasive particles, and jet diameter on the damage degree and impact depth (h). The parametric numerical studies indicates that jet diameter has the most significant influence on damage degree, followed by abrasive concentration and jet velocity, respectively, whereas the primary determinant of impact depth is the abrasive concentration followed by jet velocity and jet diameter. Based on the parametric analysis, two optimized abrasive waterjet configurations are proposed: one tailored for rock fragmentation in tunnel boring machine (TBM) operations; and another for cutting reinforced concrete piles in shield tunneling applications. These configurations aim to enhance the efficiency and sustainability of excavation and tunneling processes through improved material removal performance and reduced mechanical wear. Full article

Rock-breaking cutters are critical components in tunneling, mining, and drilling operations, where efficiency, durability, and energy consumption are paramount. Traditional cutter designs and empirical process optimization methods often fail to address the dynamic interaction between heterogeneous rock masses and tool structures, leading to premature wear, high specific energy, and suboptimal performance. Topology optimization, as an advanced computational design method, offers transformative potential for lightweight, high-strength cutter structures and adaptive cutting process control. This review systematically examines recent advancements in topology-optimized cutter design and its integration with rock-cutting mechanics. The structural innovations in cutter geometry and materials are analyzed, emphasizing solutions for stress distribution, wear/fatigue resistance, and dynamic load adaptation. The numerical methods for modeling rock–tool interactions are introduced, including discrete element method (DEM) simulations, smoothed particle hydrodynamics (SPH) methods, and machine learning (ML)-enhanced predictive models. The cutting process optimization strategies that leverage topology optimization to balance objectives such as energy efficiency, chip formation control, and tool lifespan are evaluated. Full article

The accurate modeling of dynamic soil–structure interaction processes under impact loading is critical for advancing the design of soil-embedded barrier systems. Full-scale crash testing remains the benchmark for evaluating barrier performance; however, such tests are costly, logistically demanding, and subject to variability that limits repeatability. Recent advancements in computational methods, particularly the development of large-deformation numerical schemes, such as the multi-material arbitrary Lagrangian–Eulerian (MM-ALE) and smoothed particle hydrodynamics (SPH) approaches, offer viable alternatives for simulating soil behavior under impact loading. These methods have enabled a more realistic representation of granular soil dynamics, particularly that of the Manual for Assessing Safety Hardware (MASH) strong soil, a well-graded gravelly soil commonly used in crash testing of soil-embedded barriers and safety features. This soil exhibits complex mechanical responses governed by inter-particle friction, dilatancy, confining pressure, and moisture content. Nonetheless, the predictive fidelity of these simulations is governed by the selection and implementation of soil constitutive models, which must capture the nonlinear, dilatant, and pressure-sensitive behavior of granular materials under high strain rate loading. This review critically examines the theoretical foundations and practical applications of a range of soil constitutive models embedded in the LS-DYNA hydrocode, including elastic, elastoplastic, elasto-viscoplastic, and multi-yield surface formulations. Emphasis is placed on the unique behaviors of MASH strong soil, such as confining-pressure dependence, limited elastic range, and strong dilatancy, which must be accurately represented to model the soil’s transition between solid-like and fluid-like states during impact loading. This paper addresses existing gaps in the literature by offering a structured basis for selecting and evaluating constitutive models in simulations of high-energy vehicular impact events involving soil–structure systems. This framework supports researchers working to improve the numerical analysis of impact-induced responses in soil-embedded structural systems. Full article

Against the backdrop of the global energy transition, offshore wind power has undergone rapid development. As a vital component of offshore wind power infrastructure, dry shrinkage cracking in concrete piles poses a significant threat to the safe and stable operation of offshore wind power systems. However, the fundamental mechanism of concrete pile cracking during dry shrinkage—particularly the coupled effects of moisture diffusion, meso-structural heterogeneity, and stress evolution—remains poorly understood, lacking a unified theoretical framework. This knowledge gap hinders the development of targeted anti-cracking strategies for offshore concrete structures. Hence, investigating the mechanism of dry shrinkage cracking is of substantial importance. This paper employs numerical simulation to explore the patterns and influencing factors of dry shrinkage cracking in concrete piles for offshore wind turbines, aiming to provide theoretical support for enhancing pile performance. A meshless numerical simulation method based on the smoothed particle hydrodynamics (SPH) framework is developed, which generates concrete meso-structures via a specific algorithm, discretizes the moisture diffusion equation, defines dry shrinkage stress terms, and introduces a fracture coefficient to characterize particle failure, enabling the simulation of concrete dry shrinkage cracking processes. Simulation schemes are designed for varying aggregate percentages, aggregate particle sizes, dry shrinkage coefficients, and moisture diffusion coefficients, using a 100 mm-diameter circular concrete model. Qualitative results reveal the following: Increased aggregate percentages lead to more uniform moisture diffusion, with dry shrinkage crack number and length first increasing and then decreasing; larger aggregate particle sizes exacerbate moisture diffusion non-uniformity and intensify dry shrinkage cracking; higher dry shrinkage coefficients correlate with increased crack number and length; elevated moisture diffusion coefficients accelerate surface water loss, with cracking severity first increasing and then decreasing. The proposed SPH-based meshless method effectively simulates dry shrinkage cracking in offshore wind turbine concrete piles, demonstrating the significant impact of different factors on moisture diffusion and cracking patterns. This study offers insights for applying the SPH method in related fields, deepens the understanding of concrete dry shrinkage cracking mechanisms, and provides a theoretical foundation for the design and optimization of offshore wind power concrete piles. Full article

Pipe–soil interaction encompasses the study of stress distributions and deformation mechanisms occurring between buried pipelines and their surrounding soil. Understanding the mechanical behavior of this coupled system is essential for the analysis of deformation patterns and failure modes in buried pipelines, thereby providing critical guidance for construction design and risk assessment protocols. Traditional analytical approaches have relied on classical mechanics theories and experimental methodologies; however, these approaches often incorporate excessive simplifications and assumptions that inadequately represent the complex properties of both soil and pipeline structures. Numerical simulation methodologies have emerged as viable alternatives for investigating pipe–soil interaction. Among these numerical approaches, Smoothed Particle Hydrodynamics (SPH)—an advanced Lagrangian meshless particle method—offers distinct advantages in modeling complex behaviors, including free surfaces, deformable boundaries, and large deformation scenarios that characterize pipe–soil interaction. This research establishes a pipe–soil interaction model for buried pipelines utilizing the SPH method, incorporating elastic–plastic constitutive relationships to represent soil behavior. The investigation examines lateral interaction mechanisms, vertical interaction responses in sandy soils, and the parametric influence of various soil properties on pipe–soil interaction characteristics. This study contributes insights into the application of meshfree numerical simulation techniques for pipe–soil interaction analysis, offering both engineering utility and theoretical advancement for pipeline infrastructure design and safety assessment. Full article

Accurate simulation of fluid flow around vertical cylinders is essential in numerous engineering applications, particularly in the design and assessment of offshore structures, bridge piers, and coastal defenses. This study employs the smoothed particle hydrodynamics (SPH) method to investigate the complex dynamics of breaking waves impacting a vertical pile, a scenario marked by strong free-surface deformation, turbulence, and the wave–structure interaction. The mesh-free nature of SPH makes it especially suitable for capturing such highly nonlinear and transient hydrodynamic phenomena. The primary objective of the research is to evaluate the performance of different SPH dissipation schemes, namely artificial viscosity, laminar viscosity, and sub-particle scale (SPS) turbulence models, in reproducing key hydrodynamic features. Numerical results obtained with each scheme are systematically compared against experimental data to assess their relative accuracy and physical fidelity. Specifically, the laminar + SPS model reproduced the peak horizontal wave force within 5% of experimental values, while the artificial viscosity model overestimated the force by up to 25%. The predicted wave impact occurred at a non-dimensional time of $t/T\approx 0.28$, closely matching the experimental observation. Furthermore, force and elevation predictions with the laminar + SPS model remained consistent across three particle spacings ($dp=0.05\mathrm{m},0.065\mathrm{m},0.076\mathrm{m}$), demonstrating good numerical convergence. This work provides critical insights into the suitability of SPH for modeling wave–structure interactions under breaking wave conditions and highlights the importance of proper dissipation modeling in achieving realistic simulations. The performance of the dissipation schemes remained robust across three tested particle spacings, confirming consistency in force and elevation predictions. Additionally, it underscores the sensitivity of SPH predictions to spatial resolution, highlighting the need for careful calibration to ensure robust and reliable outcomes. The study contributes to advancing SPH as a practical tool for engineering design and hazard assessment in coastal and offshore environments. Full article

In recent years, geological disasters such as water inrush during drilling and blasting operations have posed significant challenges in tunnel engineering. This paper presents a novel continuous-discrete coupling method based on LS-DYNA, combining the finite element method (FEM) and smoothed particle hydrodynamics (SPH), to simulate the water inrush phenomenon in blasting engineering. The proposed FEM-SPH model effectively captures the propagation of explosion shock waves, simulates small deformation areas with solid grids, and models water behavior using SPH. This study systematically investigates the dynamic evolution of water inrush, divided into three distinct phases: the rupture of the water-resistant rock layer, the emergence of fluid-conducting channels, and the onset of large-scale water influx. Results indicate that under blasting load, the stress of the surrounding rock increases sharply, leading to instantaneous water inrush. The FEM-SPH model demonstrates superior performance in simulating the complex interactions between blasting stress waves, water pressure, and rock mass damage. This research provides new insights and methods for water control in tunnel engineering and offers significant potential for preventing water inrush disasters in underground construction. Full article

The cold spray (CS) process has gained momentum as an additive manufacturing technology, due to its low processing temperatures. Computational modelling can accompany CS experiments to optimise deposition parameters, as well as predict coating properties and their final performance. A commonly used plasticity model is the Johnson–Cook (JC) model; however, its accuracy is limited at the high strain rates typical of cold spray. This study aims to assess the robustness of predictions using a modified JC model, particularly for two material systems of commercially pure titanium (CP-Ti) and Al6061-T6, and feedstock powders of two sizes and three morphologies. CP-Ti powders of spherical and irregular morphologies were sprayed onto CP-Ti substrates using a Titomic TKF1000 cold spray system. The cross-sectional splat profiles and flattening ratios were compared against smoothed particle hydrodynamics (SPH) simulations. The deposition process of particles was simulated using a modified JC model, implemented as an ABAQUS (2020) VUHARD user subroutine programme. The results showed that SPH simulations predicted the depth of impact, the splat profiles and the flattening ratios. Additionally, the simulations indicated that the impacting particle temperature remained below the melting point of CP-Ti throughout the process. Lastly, it was demonstrated that the irregular CP-Ti feedstock showed greater tendency of restitution than spherical feedstock. Full article

This study presents a novel unresolved SPH-DEM coupling framework to investigate the complex interactions between rising gas bubbles and sinking solid particles in multiphase systems. Traditional numerical methods often struggle with large deformations, multiphase interfaces, and computational efficiency when simulating dense particle-laden flows. To address these challenges, the proposed model leverages SPH’s Lagrangian nature to resolve fluid motion and bubble dynamics, while the DEM captures particle–particle and particle–bubble interactions. An unresolved coupling strategy is introduced to bridge the scales between fluid and particle phases, enabling efficient simulations of large-scale systems with discrete bubbles/particles. The model is validated against benchmark cases, including single bubbles rising and single particle’s sedimentation. Simulation studies reveal the effects of particle/bubble number and initial distance on phase interaction patterns and clustering behaviors. Results further illustrate the model’s capability to capture complex phenomena such as particle entrainment by bubble wakes and hindered settling in dense suspensions. The framework offers a robust and efficient tool for optimizing industrial processes like mineral flotation, where bubble–particle dynamics play a critical role. Full article

Our investigation delves into the scaling law governing planetary cratering impacts. We meticulously analyze the interplay between dimensionless parameters driving crater growth and the morphological transition of craters and construct the scaling analysis between the scale model tests and the prototype tests by numerical simulation. With practical engineering applications in mind, we design scale model tests based on the experimental setups of geotechnical centrifuges, ensuring the robust validity of test designs. This meticulous approach is integral to achieving fidelity between simulations and experimental scenarios. Validation of our scale model tests is conducted through a numerical modeling framework, coupling the finite element-smoothed particle hydrodynamics adaptive method (FE-SPH). This validation procedure serves to bolster the reliability and credibility of our methodology, facilitating an accurate depiction of the cratering mechanism. Of particular interest is the investigation into the depth-to-diameter ratio of impact craters, wherein we explore its intricate relationship with projectile diameter and gravity. Through rigorous analysis, we delineate the transition diameter at which terrestrial impact craters manifest a transition from simple to complex morphologies, thereby shedding light on the underlying dynamics of crater formation. Moreover, our study meticulously scrutinizes the relationship of crater formation time between the scaling model tests and the prototype tests. Our research underscores the consistency of the crater depth–diameter ratio in the scale model tests and the prototype tests and affirms applicability in replicating prototype tests by scale model tests. Notably, our findings reveal compelling correlations between the depth-to-diameter ratio of impact craters and gravity, as well as projectile diameter, providing valuable insights into the governing dynamics of impact crater formation. These insights not only advance our fundamental understanding of planetary cratering processes but also hold implications for practical applications in planetary science and engineering. Full article

Kinetic impact is an effective way to deal with threatening asteroids, and the momentum transfer coefficient during the impact process is an effective indicator for evaluating the impact effect. This article is based on the use of the Smoothed Particle Hydrodynamics (SPH) method to establish a simulation model of high-speed impact of flying discs on granite targets, and obtain parameters such as the shape of the splashing material and the distribution of the target damage during the impact process. An analysis was conducted on the influence of different impact velocities on the kinetic energy transfer coefficient, and it was found that the momentum transfer coefficient increased with the increase in impact velocity, from 1.59 at 5 km/s to 1.96 at 11.7 km/s. A ground high-speed impact system with a speed of over 10 km/s has been established, and the actual momentum transfer coefficient has increased from 1.73 at 7 km/s to around 2.06 at 11.7 km/s. The variation trend of kinetic energy transfer coefficients obtained from experiments and simulations is consistent, with an error of basically within 10%, and the simulation results are effective. The simulation and experimental analysis of high-speed kinetic impact can provide a reference for the engineering implementation of asteroid impact defense missions. Full article

The coordinated optimization of free-surface dynamics tracking and solid deformation computation remains a persistent challenge in casting filling simulations. While the traditional smoothed particle hydrodynamics (SPH) method suffers from prohibitive computational costs limiting practical applications, the delayed interface updates of the finite element method (FEM) compromise simulation fidelity. This study proposes a symmetric SPH-FEM coupling algorithm that integrates real-time particle-grid data exchange, and validation through ring filling simulations demonstrated close agreement with Schmid’s benchmark experiments, confirming flow field reconstruction reliability. Furthermore, bottom-injection plate experiments verified the method’s thermal modeling stability, achieving fully coupled flow–thermal–stress simulations with enhanced computational efficiency. The proposed symmetric coupling framework achieves engineering-ready simulation speeds without compromising accuracy, and this advancement establishes a novel computational tool for predicting casting defects including porosity and hot tears, significantly advancing the implementation of high-fidelity numerical simulation in foundry engineering applications. Full article

This study examines the conversion of an overflow ball mill into a new discharge system via Discrete Element Method (DEM) and Smoothed Particle Hydrodynamics (SPH) simulations, demonstrating significant performance improvements. The methodology integrates SPH to assess the effects of the slurry on energy dissipation, power loss, breakage rates, and material transport. The findings highlight significant operational inefficiencies in the overflow setup, extensive dead zones, and excessive charge volume that hinder milling efficiency by limiting grinding media interaction with the ore and reducing energy for comminution. Additionally, slurry pooling shifts the center of gravity, causing torque losses and direct material bypass to the discharge zone. Our simulations replicate these challenges and benchmark them against industrial-scale operations, identifying critical charge excesses that constrain throughput and elevate power consumption. The new proposed discharge system decouples the filling charge from the evacuation mechanism, releasing the effective volume in the mill, in addition to tackling common issues in the traditional grate discharge setups like backflow and carry-over. This arrangement substantially improved grinding efficiency, as demonstrated by enhanced breakage rates and diminished specific energy consumption. The results provide a robust framework for mill design and operational optimization, underscoring the value of integrated slurry behavior analysis in mill performance enhancement. Full article