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The existence of cracks is a key factor affecting the strength of concrete. However, traditional numerical methods still have some limitations in the simulation of crack growth in fissured concrete structures. Based on this background, the numerical treatment method of particle failure in smoothed particle hydrodynamics (SPH) is proposed, and the generation method for concrete meso-structures under the smoothed particle hydrodynamics (SPH) framework is developed. The concrete meso-models under different pre-existing micro-fissure inclinations and bridge angles (the inner tip line of the double pre-existing micro-fissure is defined as a bridge, and the angle between the bridge and the horizontal direction is defined as the bridge angle) were established, and numerical simulations of the crack propagation processes of concrete structures under tensile stress were carried out. The main findings were as follows: The concrete meso-structures and the pre-existing micro-fissures all have great impacts on the final failure modes of concrete. The stress–strain curve of the concrete model presents four typical stages. Finally, the crack initiation and propagation mechanisms of fissured concrete are discussed, and the application of smoothed particle hydrodynamics (SPH) in crack simulations of fissured concrete is prospected. [ABSTRACT FROM AUTHOR]

In this article, the performances of the SPH method to solve Shallow Water Equations SWEs with three investigation parameters were studied, such as the type of kernel functions, namely: cubic spline, Gaussian and quintic spline kernels, the number of particles used and the stabilization terms injected, specifically: Lax Friedrichs flux, artificial viscosity and two shocks Riemann solver. Three benchmarking tests make the subject of unsteady free surface flow in this study. It is 1D typical dam-break on wet and dry bottom; 2D partial dam-break on a dry floodplain and 2D partial dam-break on channel with 90° bend. The analysis of the different errors between the numerical and analytical solutions and/or the experimental data shows that the SPH method gives reliable values with the selected optimal parameters which are the cubic kernel function and the artificial viscosity term. The increase in the number of particles increases the precision but also the calculation time. [ABSTRACT FROM AUTHOR]

Slow and very slow landslides can cause severe economic damage to structures. Due to their velocity of propagation, it is possible to take action such as programmed maintenance or evacuation of affected zones. Modeling is an important tool that allows scientists, engineers, and geologists to better understand their causes and predict their propagation. There are many available models of different complexities which can be used for this purpose, ranging from very simple infinite landslide models which can be implemented in spreadsheets to fully coupled 3D models. This approach is expensive because of the time span in which the problems are studied (sometimes years), simpler methods such as depth‐integrated models could provide a good compromise between accuracy and cost. However, there, the time step limitation due to CFL condition (which states that the time step has to be slower than the ratio between the node spacing Δx$\Delta x$ and the physical velocity of the waves results in time increments which are of the order of one‐10th of a second on many occasions. This paper extends a technique that has been used in the past to glacier evolution problems using finite differences or elements to SPH depth‐integrated models for landslide propagation. The approach is based on assuming that (i) the flow is shallow, (ii) the rheological behavior determining the velocity of propagation is viscoplastic, and (iii) accelerations can be neglected. In this case, the model changes from hyperbolic to parabolic, with a time increment much larger than that of classic hyperbolic formulations. [ABSTRACT FROM AUTHOR]

The widely used weakly compressible variant of Smoothed Particle Hydrodynamics (SPH) method suffers from density and hence pressure oscillations. This is due to the particle Lagrangian nature of the SPH method in combination with weakly compressible assumption, explicit time scheme and that the substitutions of the derivatives in the SPH method are central. There are two common strategies how to suppress these issues. One of them is to use numerical diffusive term which is added to the continuity equation in order to suppress the spurious oscillation of density field. The second option is to describe the particle-particle interaction in terms of Riemann problem and use Riemann solver, which provides numerical dissipation, to handle particle interactions. In our work, we deal with the relation between these two approaches. For the constant reconstruction and for the linear reconstruction we show that the usage of Riemann solvers is due to its intrinsic numerical viscosity equivalent to the usage of diffusive terms based on even derivatives, with the difference that the Riemann solvers lead to a significantly higher diffusivity value then the standard diffusive terms. We also discuss the usage of limiters for cases with the linear reconstruction of the solution. Moreover, for both, the constant and the linear reconstruction, we analyze additional terms resulting from the employed Riemann solver also for the momentum equation. Combining these results we obtain equivalent partial differential equations, which are the result of the usage of the Riemann solver. • We show that Riemann based SPH is equivalent with the δ -WCSPH and they differ only in the diffusive coefficient. • We show additional resulting terms which are generated by the used Riemann scheme. [ABSTRACT FROM AUTHOR]

The first and fully validated smoothed particle hydrodynamics (SPH) model is presented to tackle coupled flow–deformation problems in unsaturated porous media that undergo large deformation and post-failure behaviour. Unlike the commonly adopted double-layer SPH framework for saturated soils, this paper presents a three-phase single-layer SPH model capable of predicting anisotropic seepage flows through porous media and their complete time-dependent transition from unsaturated to saturated states, as well as their influence on the mechanical behaviour of the porous media and vice versa. The mathematical framework is developed based on Biot's mixture theory and discretised using the authors' recently developed novel SPH approximation scheme for the second derivatives of a field quantity. The soil is modelled using a suction-dependent elastoplastic constitutive model, expressed in terms of effective stress and suction. In addition, an adaptive two-timescale scheme is proposed for the first time to address existing challenges in solving coupled-flow large-deformation problems that involve a significant difference in the timescale required for the solid and fluid phases. The capability of the proposed SPH model was demonstrated through fundamental consolidation tests and a large-scale rainfall-induced slope failure experiment. Very good agreements with theoretical solutions and experimental results are achieved, suggesting that the proposed SPH model can be readily extended to solve a wide range of large-scale geotechnical applications involving coupled unsaturated seepage–deformation problems. [ABSTRACT FROM AUTHOR]

This research utilised an open-sourced smoothed particle hydrodynamics (SPH) tool to model and predict the change in wave-induced forces and motions of a free-floating bergy bits approaching a fixed structure in regular waves. Simulation parameters, including particle resolution, fluid viscosity, initial wave condition and boundary treatments, are varied, and their effect on the load imparted to the bergy bit and the structure are investigated. The predicted motions are compared with previously published physical measurements for corresponding scenarios. Both predictions and measurements showed that, in regular waves, the surge motion slowed as the bergy bit approached the structure, and the heave motion increased. For wave loading on bergy bits, the agreement with the experimental data for the root mean square (RMS) force was within 2%. The pressure and velocity fields of the wave–structure–bergy bit interactions are discussed in light of the SPH predictions. This work confirms that the SPH model can accurately capture viscosity–dominated interactions, hydrodynamic damping, and eccentric impact like phenomena and predict both the impact and hydrodynamic loads due to a bergy bit drifting in waves towards a fixed offshore structure. [ABSTRACT FROM AUTHOR]

The non-uniform distributed pressure of impact wave is usually simplified into concentrated or uniform load equivalently in the optimization design of constrained layer damping structure. However, for the thin-walled structure, it becomes necessary to regard the load as a non-uniform distribution. In this paper, a topology optimization approach is proposed considering the blast load with non-uniform distribution, aiming to unveil its impact on optimization layouts and dynamic responses. Initially, the smoothed particle hydrodynamics (SPH) algorithm is used to obtain the blast pressure what are extracted and integrated into the optimization model. Subsequently, the relative density is regarded as design variable. The construction of material penalty model and the topology optimization model are based on polynomial interpolation scheme (PIS). The sensitivity of objective function is deduced employing an improved adjoint variable method (AVM) to fit the load forms, and the Newmark- β method is used to calculate the dynamic response. The optimization criterion (OC) is adopted to update the design variables. Finally, two numerical examples are used to exhibit the validity and accuracy of the presented methodology. The findings indicate that the distributed form, spread velocity, excited position and excited amplitude of the blast load all exert a notable influence on optimization results and dynamic response. These results underscore the valuable engineering application of this research and introduce a fresh perspective to the challenge of topology optimization under the blast case. [ABSTRACT FROM AUTHOR]

The ingested particles or debris will cause high-speed & low-energy impact to the hot end components of aeroengine. Few literature focus on the projectile impact of SiC/SiC with Environmental Barrier Coating(EBC). The impact of 2 mm projectile was specially studied for Si/Yb2Si2O7/Yb2SiO5-SiC/SiC. Gas gun system was used to conduct impact testing at the speed of 3 m/s∼353m/s. The optical microscope, Scanning Electronic Microscope(SEM), micro CT were used to observe the impact and tension after impact(TAI) damage. For TAI, Digital Image Correlation (DIC) was used to conduct the full-field strain detection around the impact point. Meanwhile, the Smoothed Particle Hydrodynamics (SPH) methodology was programmed in C++ and developed to simulate SiC/SiC impact problem by introducing modified Hashin-Rotem criteria, extending interface method to 3D and adding GPU accelerated algorithm. The results indicate that threshold velocities of EBC huge peeling and SiC/SiC penetration are different, TAI residual strength also has extinct threshold at the velocity of 246 m/s with 37.1% declining extent, and the impact pit depth of SPH simulation is in good agreement with the experiment. [ABSTRACT FROM AUTHOR]

In rural areas, landslides can bury houses and result in major disasters in affected areas, which can greatly hinder local economic development and construction. When landslides occur, sliding debris can result in large impact forces, causing varying degrees of damage to building structures. Given the great harm caused by landslides, this paper studies the prediction of dynamic response characteristics of building structures under the impact of the Zhengjiamo landslide. The engineering geological background of the Zhengjiamo landslide is analyzed in detail via field investigations. Then, a numerical method is presented to simulate the runout process of the sliding debris, and the runout process and final deposition area are studied. A node-to-surface contact algorithm is adopted to transfer the displacements and contact forces between the sliding debris and the building. The building structure is simulated via the finite element method (FEM). The sliding debris is simulated via the smoothed particle hydrodynamics (SPH) method. An element erosion algorithm is adopted to simulate the destruction process. The SPH-FEM fluid–structure coupling method is implemented to simulate the landslide dynamic disaster process (the impact behavior for the building). The destruction process is considered in the interactions between the sliding debris and the building on the three-dimensional terrain. The landslide motion during each stage is analyzed, including the sliding, energy dissipation, impact, and damage to the building structure. The maximum runout of the landslide is about 280 m. The maximum stress of the impact on the building is 2 × 106 Pa. The impact speed of the sliding body is generally 16.5–24.07 m/s. On the basis of this, the disaster background, disaster status, and prediction of the landslide disaster effect are studied to provide new insights into landslide disaster prevention and reduction. [ABSTRACT FROM AUTHOR]

The fatigue crack propagation analysis based on the SPH framework "SPH-Fatigue" is accelerated by using the single precision program on GPU. It is found that the single precision program slightly disorders the stress wave but doubles the computational speed. In addition, the computational results of the fatigue crack propagation by the single precision program show almost the same crack shapes as the experimental ones. Accordingly, it is concluded that the use of the single precision program is one of the choices to accelerate the SPH-Fatigue computation. [ABSTRACT FROM AUTHOR]

The landslide is one of the most serious natural hazards that could greatly change the natural and man-made environments through the high-speed spreading and long-distance sliding. It has been widely accepted that the geomaterials are usually heterogenous with the nature of spatial variability that will affect the spatiotemporal evolution of a landslide. To address this problem, this study proposed a stochastic non-Newtonian smoothed particle hydrodynamics (SPH) model to analyze the flow process and run-out distance of landslides under spatially variable cohesion. Based on a conceptual landslide, the sliding process and run-out distance of each random sample were obtained from the Monte Carlo simulations. According to analysis results, the post-failure process and run-out distance distribution were discussed to reveal the influences of mean value ad coefficient of variation. Finally, simulated data were fitted to infer which type of distribution the run-out distance belongs to, and the determination coefficients for different distribution types were calculated to verify the proposed inference. It can be found that the average run-out distance changes with the mean cohesion, the distribution becomes wider as the coefficient of variation increases and the landslide run-out distance has the same distribution type as that of cohesion. [ABSTRACT FROM AUTHOR]

In many industrial, automobile, and defence products, there is a need to produce holes of a diameter larger than 25 mm. This requires the use of heavy machines, which requires more time and produces higher cutting forces. The cutting time and cutting forces can be considerably reduced by using trepanning in place of conventional drilling operations. Though a few trepanning tools are available commercially, they are costly, and not much literature is available on the design of such tools. Conventional design approach and manufacturing, and then experimental validation if the tool is costly and time-consuming. Hence, this research work follows finite element analysis and simulation for the tool design, followed by experimental validation of the performance. The developed trepanning tool uses two carbide parting inserts to produce holes of 40 mm in diameter in a 40 mm thick stainless steel 304 work-piece. The effects of machining parameters, cutting speed and feed rate, on the torque and thrust force were studied. The experimental and simulation results for the torque and thrust force were found to be in good agreement and the percentage error was less than 7% and 15%, respectively. The average thrust forces of 344 N and 258 N and average torque of 18.87 Nm and 6.97 Nm were observed for the two levels of cutting speed and feed rate chosen for machining trials. This simulation-based design approach can be used for developing similar cutting tools. The proposed methodology of CAD design, analysis, physical tool development, and then its performance validation could lead to an increase in innovation and a time and cost reduction during the development process of any tool used for machining. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Debris flow is a highly destructive natural disaster, necessitating accurate simulation and prediction. Existing simulation methods tend to be overly simplified, neglecting the three‐dimensional complexity and multiphase fluid interactions, and they also lack comprehensive consideration of soil conditions. We propose a novel two‐particle debris flow simulation method based on smoothed particle hydrodynamics (SPH) for enhanced accuracy. Our method employs a sophisticated two‐particle model coupling debris flow dynamics with SPH to simulate fluid‐solid interaction effectively, which considers various soil factors, dividing terrain into variable and fixed areas, incorporating soil impact factors for realistic simulation. By dynamically updating positions and reconstructing surfaces, and employing GPU and hash lookup acceleration methods, we achieve accurate simulation with significantly efficiency. Experimental results validate the effectiveness of our method across different conditions, making it valuable for debris flow risk assessment in natural disaster management. [ABSTRACT FROM AUTHOR]

Total Lagrangian SPH (TLSPH) offers many advantages that can overcome instability and computational time issues. However, it is not naturally applicable to problems with contact. Many problems in solid dynamics and structural analysis require contact definition. In order to use the total Lagrangian formulation, further development for the contact algorithm is required. This research proposes an algorithm to implement inter‐particle contact in TLSPH using an adaptive hybrid‐kernel scheme for the first time. A combination of the updated and total Lagrangian formulations at the contact surface is introduced, in which the kernel type change automatically when particles from a different body are detected. In kernel change from the updated to the total Lagrangian formulation, the gradient correction cannot be performed using a common correction method because different frames of reference are used. Therefore, a hybrid‐kernel correction technique is proposed to maintain the zeroth‐ and first‐order completeness. Then, the contact force is obtained from the inter‐particle force using the conservation of momentum. The proposed method does not require a user‐defined parameter that makes the application straightforward. Based on the test, the proposed method agrees well with the data available in published literature and the finite element method. Compared with the contact method in classical SPH, the proposed TLSPH shows a significant stability improvement. [ABSTRACT FROM AUTHOR]

This article presents a novel approach to calibrating the digital twin of a laboratory mill used for copper ore milling. By integrating computer vision techniques for real-time data extraction and employing DualSPHysics simulations for various milling scenarios, including balls only, balls with ore, and balls with slurry, we achieve a high degree of accuracy in matching the digital twin's behavior with actual mill operations. The calibration process is detailed for mills with three different diameters, highlighting the adjustments in simulation parameters necessary to account for the absence of ore. Understanding the dynamics between the suspension within the mill and the operation of the grinders is crucial for the future improvement of the grinding process. This knowledge paves the way for optimizing the process, not only in terms of the quality of the end product but primarily in terms of energy efficiency. A profound understanding of these interactions will enable engineers and technologists to design mills and grinding processes in a way that maximizes efficiency while minimizing energy consumption. [ABSTRACT FROM AUTHOR]

In order to explore the removal mechanism and influence law of grinding force in grinding SiC ceramics, the simulation model of single abrasive striking SiC ceramics was established based on the SPH (smoothed particle hydrodynamics) method, and the crack generation and propagation mechanism during grinding SiC ceramics were analyzed; the effect of grinding velocity (vs), feeding rate (vw) and grinding depth (ap) on the removal mechanism, the normal grinding force and tangential grinding force of grinding SiC ceramics were analyzed by the single factor experiment. The results showed that the abrasives striking the workpiece lead to the generation of the median cracks and the transverse cracks. With the increase of abrasive pressing depth, the transverse crack expands to the material surface, and when the transverse crack expands to the material surface, the brittle fracture occurs. With the increase of vs, the decrease of vw and ap, and the decrease of the area and depth of the pits on the grinding surface, the plastic removal area becomes larger, and the normal grinding force and tangential grinding force both decrease. These results may provide an important basis for high‐efficiency and low‐ damage machining of SiC ceramic components. [ABSTRACT FROM AUTHOR]

Performance of a new incompressible smoothed particle hydrodynamics (I-SPH) model for simulating free surface flows using Lagrangian description of motion is numerically evaluated. In the SPH method, kernel or weight functions are used for approximation of a function and its spatial derivatives based on the theory of integral interpolants exhibiting poor accuracy. In this study, the pressure field is obtained by solving a pressure Poisson equation that is derived from a two-step prediction–correction approach applied for temporal discretization of the governing equations of fluid flows and enforcement of incompressibility. A newly developed gradient model in the context of the mesh-less moving particle semi-implicit (MPS) method is applied to improve the standard gradient and Laplacian models of I-SPH method in the proposed approach. The higher accuracy of the modified SPH scheme, which is a kernel gradient-free model, in comparison with the standard I-SPH method is validated trough solving the classic benchmark problems including the dam break flow, solitary wave propagation, standing wave motion, liquid sloshing and water drop stretching. [ABSTRACT FROM AUTHOR]

Landslide-generated impulsive waves (LGWs) in reservoir areas can seriously threaten waterway safety as well as human life and properties around the two side slopes. The risk reduction and mitigation of such a hazard require the accurate prediction of near-field wave characteristics, such as wave amplitude and run-up. However, near-field LGW involves complicated fluid-solid interactions. Furthermore, the wave characteristics are closely related to various aspects, including the geometry and physical features of the slide, river, and body of water. However, the empirical or analytical methods used for rough estimation cannot derive accurate results, especially for deformable landslides, due to their significant geometry changes during the sliding process. In this study, the near-field waves generated by deformable landslides were simulated by smoothed particle hydrodynamics (SPH) based on multiphase flow. The deformable landslides were generalized as a kind of viscous flow by adopting the Herschel-Bulkley-Papanastasiou (HBP)-based nonNewtonian rheology model. The HBP model is capable of producing deformable landslide dynamics even though the high-speed sliding process is involved. In this study, an idealized experiment case originating from Lituya LGW and a practical case of Gongjiafang LGW were reproduced for verification and demonstration. The simulation results of both cases show satisfactory consistency with the experiment/investigation data in terms of landslide movement and near-field impulsive wave characteristics, thus indicating the applicability and accuracy of the proposed method. Finally, the effects of the HBP model's rheological parameters on the landslide dynamics and near-field wave characteristics are discussed, providing a parameter calibration method along with suggestions for further applications. [ABSTRACT FROM AUTHOR]

The integration of artificial intelligence (AI) into computational fluid dynamics (CFD) has significantly expanded the scope of fluid modeling, allowing enhanced analysis capabilities and improved simulation performance. While Eulerian methods already benefit extensively from AI, notably in reliable weather prediction, the application of AI to Lagrangian methods remains less consolidated. Smoothed particle hydrodynamics (SPH) is a Lagrangian mesh-less numerical method for CFD with well-established advantages for the simulation of highly dynamic free-surface flows. Here, we explore an application of AI to SPH simulations, utilizing an artificial neural network (ANN) to estimate hydrodynamic forces between particle pairs, learning from SPH-simulated results. A model of this nature, which emulates the mathematical representation of physics, is termed an emulator. We examine the physical significance of the emulator, presenting its applications in benchmark tests, assessing its faithfulness to traditional SPH simulations, and highlighting its ability to generalize and simulate test cases with varying levels of complexity beyond its training data.

The landslide-induced overtopping waves on the dam possesses the potential to release significant energy, presenting a severe hazard to infrastructures and human lives downstream. To gain insight into the complex dynamics of landslide-wave-dam interactions, this study systematically investigates the relationship between landslide-related influential factors and the characteristics of resultant overtopping waves with different bed connection schemes. The validated Smoothed Particle Hydrodynamics (SPH) framework is applied to simulate 58 well-designed scenarios, incorporating varying bed connection schemes and diverse influential factors. Results indicate that the landslide position exerts minimal influence on overtopping waves, whereas the initial water depth and landslide size demonstrate a significant impact. Notably, arc-shaped connection can lead to more significant overtopping waves compared to rigid sloped connection due to lower dissipation resulted from collisions. The maximum ratio between the arc-shaped and rigid sloped for overtopping wave height and safety term are 1.688 and 1.659. In addition, we propose prediction equations for maximum overtopping wave height, safety term, and individual overtopping volume, quantitatively assessing the impact of diverse initial influential factors on overtopping waves. The presented SPH framework and prediction equations improve understanding of landslide-induced overtopping waves, providing a valuable guide for disaster prevention and mitigation efforts.Highlights An SPH framework is presented to simulate landslide-induced wave overtopping.Rigid sloped connection generates smaller overtopping waves than arc-shaped connection due to high energy dissipation.Initial water depth and landslide size dominantly influence the overtopping waves.A systematic method is presented to derive predictive equations.We propose prediction equations correlating influential factors with overtopping wave characteristics.

AbstractFilling ability is one of the prominent rheological properties of the self-compacting concrete (SCC), which has been studied in this research work deploying the functional behavior of the concrete through the Orimet apparatus using the coupled ANSYS-SPH interface. Seven (7) model cases: Case 1: 0% coarse particles and 100% fine particles, Case 2: 60% coarse particles and 40% fine particles, Case 3: 55% coarse particles and 45% fine particles, Case 4: 50% coarse particles and 50% fine particles, Case 5: 45% coarse particles and 55% fine particles, Case 6: 40% coarse particles and 60% fine particles and Case 7: 100% coarse particles and 0% fine particles were studied and optimized. The maximum size of the coarse aggregates considered is 20 mm and that of the fine aggregates is below 4 mm. The Bingham model properties for the multiphysics (SPH)-ANSYS models’ simulation are; Viscosity = 20 ≤ μ ≤ 100 and the Yield stress = 50 [Formula: see text] standard flow time, t (s) ranges; 0 ≤ t ≤ 6, and the Orimet volume is 10 l. The minimum boundary flow time, which represents the time (0 ≤ t ≤ 6) it takes for the SCC to completely flow through a specified distance, typically measured in seconds was modeled for in the seven (7) model cases. The first case; 0%C mixed with 100%F flowed out completely in 6 s, second case; 40%C mixed with 60%F completely flowed out in 5 s, third case; 45%C mixed with 55%F completely flowed out in 9 s, fourth case; 50%C mixed with 50%F completely flowed out in 12 s, fifth case; 55%C mixed with 45%F completely flowed out in 11 s, sixth case; 60%C mixed with 40%F completely flowed out in 12 s, and lastly, the 7th case; 100%C mixed with 0%F completely flowed out in 20 s. The minimum flow time was considered alongside other relevant parameters and tests, such as slump flow, passing ability, segregation resistance, and rheological properties (stresses), to comprehensively assess the filling ability of SCC in this model. By considering these factors and the optimized mix (40%C + 60%F:5 s), engineers and researchers can optimize the SCC mix design to achieve the desired flowability and filling performance for their specific construction applications. The multiphase optimized mix (40%C + 60%F:5 s) was further simulated using the coupled interface of the ANSYS-SPH platform operating with the CFX command at air temperature of 25 °C, which incorporated the studied density of 2400 kg/m3, plastic viscosity boundary, yield stress, and aggregate sampling. The model simulation operated on total number of nodes = 143,083, total number of elements = 753,292, total number of tetrahedrons = 753,292, and total number of faces = 68,488, and produced Dynamic Viscosity = 1.831E-05 kg m−1 s−1, Thermal Conductivity = 2.61E-02 W m−1 K−1, Absorption Coefficient = 0.01 m−1, Thermal Conductivity = 2.61E-02 W m−1 K−1, Refractive Index = 1.0 m m−1, Molar Mass = 1 kg kmol−1, Specific Heat Capacity = 8.80E + 02 J kg−1 K−1, Normal Speed = 165 mm s−1, Pressure Profile Blend = 0.05, and Maximum Partition Smoothing Sweeps = 100. Also, the Global Length = 1.9144E-01, Minimum Extent = 1.1800E-01, Maximum Extent = 6.5976E-01, Density = 1.1850E + 00, Velocity = 1.6500E-01, Advection Time = 1.1602E + 00, and Reynolds Number = 2.0443E + 03. The simulation also produced wall forces and moments on the wall of the Orimet for the optimized mix containing 40%C + 60%F:5 s flow mix as follows; pressure force on wall; −3.0996E-08, −2.0863E-07, and −3.5048E-04 for x-component, y-component, and z-component, respectively, viscous force on wall; −5.5332E-10, −9.2298E-10, and −2.7250E-05 for the x-, y-, and z-components, respectively, pressure moment on wall; −5.0051E-05, 3.1362E-06, and 2.2774E-09 for the x-, y-, and z-components, respectively and viscous moment on wall; −3.8925E-06, 2.4396E-07, and −7.2693E-11 for the x-, y-, and z-components, respectively. Also, the maximum residuals were located at node 110413 for the pressure, node 76766 for the K-TurbKE, and node 110724 for the E-Diss.K. Ideally, the mix, 40%C + 60%F:5 s has been proposed as the mix with the most efficient flow to achieve the filling ability for sustainable structural concrete construction.

Herein, the polycrystalline CuCr 2 O 4 (CCO) electro-ceramic was prepared via the sol-gel self-combustion route. The X-ray powder diffraction analysis at room temperature revealed that the CCO chromite was synthesized in a single phase tetragonally distorted normal spinel structure with I 4 1 / amd space group. Transmission electron microscopy (TEM) and selected area electron diffraction (SAED) investigated the polycrystalline nature of the compound. The microstructural analysis by field emission scanning electron microscopy (FESEM) explored the surface morphology of micron-sized grains (Gs) distinguished by well-pronounced grain boundaries (GBs) available for electrical response of the material. The color mapping images of elements by energy-dispersive X-ray spectroscopy (EDS) divulged the homogeneous distribution of elements in the compound. The surface chemistry of the compound was studied by X-ray photoelectron spectroscopy (XPS). This information helped in understanding the electronic states of the ions contributing to the electrical networks and mechanisms responsible for the charge transport within the CCO system. The dielectric relaxation and electrical transport properties were analyzed using complex impedance spectroscopy (CIS) over the experimental range of frequency and temperature from 40 Hz to 1 MHz and 243–493 K, respectively. The experimental complex impedance data were analyzed by R G Q G R GB Q GB equivalent circuit model which resolved the electro-active contributions of bulk and interface of the CCO spinel to its electrical dynamics. The dispersion in AC conductivity was explained by Jonscher's double power law which provided evidence of small polaron hopping (SPH) as a dominant transport mechanism governing electrical conduction in the compound. The temperature-dependent DC conductivity pattern exhibited an Arrhenius-like behavior that followed Mott and Davis's model of SPH. The analysis of complex electrical modulus M * (ω , T) professed the localized and de-localized movements of the charge carriers. The dielectric permittivity response of CCO followed Havriliak-Negami (HN) phenomenology that divulged the existence of non-Debye type dielectric relaxation processes. The interfacial polarization was observed to be accountable for the dispersion in dielectric loss spectra. [ABSTRACT FROM AUTHOR]

We present a framework that captures sparse Lagrangian flow information from a volume of real liquid and reconstructs its detailed kinematic information in real time. Our framework can perform flow reconstruction even when the liquid is disturbed by an object of unknown movement and shape. Through a large dataset of liquid moving under external disturbance, an agent is trained using reinforcement learning to reproduce the target flow kinematics with only the captured sparse information as inputs while remaining oblivious to the movement and the shape of the disturbance sources. To ensure that the underlying simulation model faithfully obeys physical reality, we also optimize the viscosity parameters in Smoothed Particle Hydrodynamics (SPH) using classical fluid dynamics knowledge and gradient-based optimization. By quantitatively comparing the reconstruction results against real-world and simulated ground truth, we verified that our reconstruction method is resilient to different agitation patterns. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Applied Mechanics is the property of Chinese Journal of Applied Mechanics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

AbstractIn order to study the whole process of the high temperature liquid slag fly ash produced after the combustion of high alkali coal as power coal in the boiler furnace, which moves in the furnace and impinges on the water wall, the heat exchange occurs and then the cooling phase transformation deposits and slags, and the possible factors of slagging particles are studied by changing the environmental variables. In this paper, based on Smoothed Particle Hydrodynamics (SPH), the dynamic behavior of boiler molten ash impacting vertical wall is studied, and the flow spreading and solidification model of molten slag impacting vertical wall is established. Thus, the process of phase change deposition of slag particles against wall is simulated. By observing the phase distribution of slag and the change in spreading process, the complete process of the slag particles hitting the wall, spreading, shrinking and solidifying is analyzed. Based on the cohesive and repulsive surface force method, a temperature-dependent surface tension model is established to simulate the effect of surface tension on flow characteristics when molten ash impinges on low-temperature vertical walls. The influences of slag impact velocity, initial temperature and water wall temperature on deformation and solidification heat transfer are discussed. The results show that the initial velocity and initial temperature of slag particles affect the phase change deposition velocity and the final spreading factor of slag, while the temperature of the water wall has little effect on the deposition deformation and solidification process of slag. [ABSTRACT FROM AUTHOR]

Modeling strong shock waves in fluids remains a persistent challenge in computational physics. Essential to research efforts in industry and defense, numerous methods have been devised to improve the accuracy and efficiency of shock simulations. A novel, hybrid Finite Volume Method (FVM)-Smoothed Particle Hydrodynamics (SPH) approach is capable of further improving efficiency and retaining accuracy by exploiting the favorable characteristics of each respective method. This hybrid approach is presented for shock capturing in compressible fluids. The Python framework Pyro2 is employed to simulate a coarse FVM mesh, while the Python framework PySPH is utilized to model the fluid in regions with high gradients through SPH particles. The performance of the hybrid FVM-SPH scheme, compared to the individual FVM and SPH methods, is assessed in 1 kt and 10 kt blast simulations. Our results indicate that the hybrid approach offers higher computational efficiency than SPH while preserving its accuracy and characteristics. The hybrid approach had a relative speedup of 11.3x and 22.3x over the FVM and SPH approaches for the 1 kt simulation and a relative speedup of 14.7x and 20.9x over the FVM and SPH approaches for the 10 kt simulation. The hybrid SPH algorithm enables future compressible fluid simulations with more extensive capabilities than grid-based methods alone, presenting potential applications in modeling fluid-structure interactions and solid deformation and fracturing in blast simulations. [ABSTRACT FROM AUTHOR]

The landslide dynamics model is one of the methods for evaluating landslide motion processes, contributing to disaster prevention and mitigation. With the advancement of science and technology, GIS has become the mainstream platform for landslide simulation. However, the three-dimensional movement of landslides is intricate, leading to a lack of methods for three-dimensional landslide numerical simulation on GIS platforms. In this paper, we propose a three-dimensional, two-phase landslide dynamics model. Through the proposed solution, three-dimensional modeling and numerical simulation of landslides can be achieved on GIS platforms. Simultaneously, drawing inspiration from the SPH kernel functions, we visualize the results of the three-dimensional model on the GIS platform. Simulation of the Yigong landslide demonstrates that our solution can realize three-dimensional landslide simulation on the GIS platform. Our model adeptly captures numerous details in the landslide motion process. However, constrained by the inherent limitations of the three-dimensional model, the model results are susceptible to numerical oscillations and diffusion, with the accuracy of the model being controlled by grid partitioning. [ABSTRACT FROM AUTHOR]

We consider the micro- and the macro-scale to investigate the motion of single grains in a dilute suspension under shear flow and Poiseuille flow to analyze effects like shear-wall migration and rolling of grains as observed in physical experiments. To be able to simulate the behavior of fresh concrete or mud flow, as realistically as possible, we are taking into account a non-Newtonian Bingham–Papanastasiou rheology for the carrier fluid. Due to a surface coupled approach, Smoothed Particle Hydrodynamics (SPH) gives the opportunity to consider both, the motion of a solid particle, by tracking its center of mass and also surface points, and the interaction and influence on the near field of the velocity field in the fluid phase. We show an independence of the motion of solid grains from the surrounding carrier fluid. While the macroscopic flow reaches a stationary flow field quite fast, the motion of the solid grains still oscillates between parts of the fluid that flow with different velocities and does not show a stable steady state. Providing a comparison between the motion in a Newtonian and a non-Newtonian fluid, we point out the differences and thus the importance of the choice of the material model for the carrier fluid in numerical simulations. • SPH simulations of suspensions with Newtonian or non-Newtonian carrier fluid. • Detailed analysis of the motion of solid grains in a suspension on different scales. • Focus on the analysis of the near velocity field at the surface of solid grains. [Display omitted] [ABSTRACT FROM AUTHOR]

Mini-tiller is an indispensable agricultural machinery in hilly and mountainous areas of China. Rotary blade is an important working part of mini-tiller, which directly affects the operation quality and power consumption of mini-tiller. In order to reduce the cutting resistance and power consumption of the rotary blade of mini-tiller, the cutting process of the rotary blade was analyzed by numerical simulation, and the tangential bending radius (R), bending angle (β) and edge thickness (c) of the rotary blade were selected as factors to optimize it. After comparing the cutting resistance and cutting power consumption of the rotary blade before and after optimization, the results show that the cutting force of the optimized rotary blade is smaller than that of the rotary blade before optimization. The cutting power consumption of the optimized rotary blade is 2.4% lower than that of the unoptimized rotary blade, which achieves the purpose of drag reduction and consumption reduction. [ABSTRACT FROM AUTHOR]

Filling ability is one of the prominent rheological properties of the self-compacting concrete (SCC), which has been studied in this research work deploying the functional behavior of the concrete through the Orimet apparatus using the coupled ANSYS-SPH interface. Seven (7) model cases: Case 1: 0% coarse particles and 100% fine particles, Case 2: 60% coarse particles and 40% fine particles, Case 3: 55% coarse particles and 45% fine particles, Case 4: 50% coarse particles and 50% fine particles, Case 5: 45% coarse particles and 55% fine particles, Case 6: 40% coarse particles and 60% fine particles and Case 7: 100% coarse particles and 0% fine particles were studied and optimized. The maximum size of the coarse aggregates considered is 20 mm and that of the fine aggregates is below 4 mm. The Bingham model properties for the multiphysics (SPH)-ANSYS models' simulation are; Viscosity = 20 ≤ μ ≤ 100 and the Yield stress = 50 ≤ τ0 ≤ 200, standard flow time, t (s) ranges; 0 ≤ t ≤ 6, and the Orimet volume is 10 l. The minimum boundary flow time, which represents the time (0 ≤ t ≤ 6) it takes for the SCC to completely flow through a specified distance, typically measured in seconds was modeled for in the seven (7) model cases. The first case; 0%C mixed with 100%F flowed out completely in 6 s, second case; 40%C mixed with 60%F completely flowed out in 5 s, third case; 45%C mixed with 55%F completely flowed out in 9 s, fourth case; 50%C mixed with 50%F completely flowed out in 12 s, fifth case; 55%C mixed with 45%F completely flowed out in 11 s, sixth case; 60%C mixed with 40%F completely flowed out in 12 s, and lastly, the 7th case; 100%C mixed with 0%F completely flowed out in 20 s. The minimum flow time was considered alongside other relevant parameters and tests, such as slump flow, passing ability, segregation resistance, and rheological properties (stresses), to comprehensively assess the filling ability of SCC in this model. By considering these factors and the optimized mix (40%C + 60%F:5 s), engineers and researchers can optimize the SCC mix design to achieve the desired flowability and filling performance for their specific construction applications. The multiphase optimized mix (40%C + 60%F:5 s) was further simulated using the coupled interface of the ANSYS-SPH platform operating with the CFX command at air temperature of 25 °C, which incorporated the studied density of 2400 kg/m³, plastic viscosity boundary, yield stress, and aggregate sampling. The model simulation operated on total number of nodes = 143,083, total number of elements = 753,292, total number of tetrahedrons = 753,292, and total number of faces = 68,488, and produced Dynamic Viscosity = 1.831E-05 kg m-1 s-1, Thermal Conductivity = 2.61E-02 W m-1 K-1, Absorption Coefficient = 0.01 m-1, Thermal Conductivity = 2.61E-02 W m-1 K-1, Refractive Index = 1.0 m m-1, Molar Mass = 1 kg kmol-1, Specific Heat Capacity = 8.80E + 02 J kg-1 K-1, Normal Speed = 165 mm s-1, Pressure Profile Blend = 0.05, and Maximum Partition Smoothing Sweeps = 100. Also, the Global Length = 1.9144E-01, Minimum Extent = 1.1800E-01, Maximum Extent = 6.5976E-01, Density = 1.1850E + 00, Velocity = 1.6500E-01, Advection Time = 1.1602E + 00, and Reynolds Number = 2.0443E + 03. The simulation also produced wall forces and moments on the wall of the Orimet for the optimized mix containing 40%C + 60%F:5 s flow mix as follows; pressure force on wall; -3.0996E-08, -2.0863E-07, and -3.5048E-04 for x-component, y-component, and z-component, respectively, viscous force on wall; -5.5332E-10, -9.2298E-10, and -2.7250E-05 for the x-, y-, and z-components, respectively, pressure moment on wall; -5.0051E-05, 3.1362E-06, and 2.2774E-09 for the x-, y-, and z-components, respectively and viscous moment on wall; -3.8925E-06, 2.4396E-07, and -7.2693E-11 for the x-, y-, and z-components, respectively. Also, the maximum residuals were located at node 110413 for the pressure, node 76766 for the K-TurbKE, and node 110724 for the E-Diss.K. Ideally, the mix, 40%C + 60%F:5 s has been proposed as the mix with the most efficient flow to achieve the filling ability for sustainable structural concrete construction. [ABSTRACT FROM AUTHOR]

Background: Ultraviolet (UV) is the main reason to cause photoaging skin which not only hinders beauty, brings the patients with psychological burden, but also pathologically leads to the occurrence of tumors in skin. Objective: This study goes into the inhibitory effect and mechanism of seawater pearl hydrolysate (SPH) to address human skin keratinocytes photoaging induced by UVB. Methods: The photoaging model of Hacat cell was constructed by UVB irradiation, the levels of oxidative stress, apoptosis, aging, autophagy and autophagy‐related protein and signal pathway expression were assessed to characterize the inhibitory effect and mechanism of SPH on photoaging Hacat cell. Results: Seawater pearl hydrolysate significantly accelerated (p < 0.05) the activities of superoxide dismutase, catalase, and glutathione peroxidase, and markedly reduced (p < 0.05) the contents of reactive oxygen species (ROS), malondialdehyde, protein carbonyl compound and nitrosylated tyrosine protein, aging level, apoptosis rate in Hacat cell induced by 200 mJ cm−2 UVB after 24 and 48 h of culture; high dose SPH significantly raised (p < 0.05) relative expression level of p‐Akt, p‐mTOR proteins, and markedly decreased (p < 0.05) relative expression level of LC3II protein, p‐AMPK, and autophagy level in Hacat cell induced by 200 mJ cm−2 UVB, or in combination with the intervention of PI3K inhibitor or AMPK overexpression after 48 h of culture. Conclusion: Seawater pearl hydrolysate can effectively inhibit 200 mJ cm−2 UVB‐induced photoaging of Hacat cells. The mechanism indicates removing the excessive ROS through increasing the antioxidation of photoaging Hacat cells. Once redundant ROS is eliminated, SPH works to reduce AMPK, increase PI3K‐Akt pathway expression, activate mTOR pathway to lowdown autophagy level, and as a result, inhibit apoptosis and aging in photoaging Hacat cells. [ABSTRACT FROM AUTHOR]

Fine cracks are easy to occur in the processing of monocrystalline silicon, which affects the surface processing quality. Laser assisted machining (LAM) can soften the substitute machining area, effectively reduce the cutting force, extend the tool life and improve the surface quality. In this paper, a thermo mechanical coupled smooth particle model is established to simulate the laser assisted turning process of single crystal silicon. Under different temperature conditions, crack propagation damage and cutting stress are explored. The influence of speed and cutting depth on surface roughness. Finally, the accuracy of simulation results is verified by laser assisted cutting experiments. The results show that increasing the temperature is beneficial to the plastic cutting of monocrystalline silicon. With the increase of the cutting zone temperature, the tool stress gradually decreases. The tool stress at 300 ℃ is about 50% lower than that at room temperature, and the surface processing quality is significantly improved. At 600 ℃, the chip is a plastic flow sawtooth line, and the plasticity is greatly improved. During cutting, a smaller cutting depth shall be selected, the rotating speed shall be lower than 4 500 r/min, and the surface roughness Sa of monocrystalline silicon can be less than 1 nm.

Explosive welding has been extensively harnessed to create composite materials for various applications in recent years. Integrating 3D-printed metal materials in explosive welding is important for future research and the broader application of 3D-printed materials in practical scenarios. In this study, 3D Printing-SUS316L/A1060 was employed for explosive welding to assess the feasibility of using 3D printed materials in this process and to examine the microstructural changes at the interface, emphasizing changes in the pores of the 3D-printed materials during welding. The resulting joint microstructures were analyzed using a scanning electron microscope (SEM) alongside an energy-dispersive X-ray spectroscopy (EDS) system and electron backscatter diffraction (EBSD). Tensile, three-point bending, Vickers-hardness, and nanoindentation tests were conducted to investigate the mechanical properties. X-ray computed tomography (XCT) scanning was utilized to observe the weld material in three dimensions and measure porosity. Moreover, ANSYS AUTODYN numerical simulation was employed to study the welding interface evolution mechanism and pore changes and further investigate the explosive welding window. The results indicate that explosive welding can successfully merge 3D-printed SUS316L and pure aluminum A1060. Both microstructure investigation and mechanical property testing validated that the bonding was of good quality, and simulation and welding windows corresponded with the experimental results.

The existence of cracks is a key factor affecting the strength of concrete. However, traditional numerical methods still have some limitations in the simulation of crack growth in fissured concrete structures. Based on this background, the numerical treatment method of particle failure in smoothed particle hydrodynamics (SPH) is proposed, and the generation method for concrete meso-structures under the smoothed particle hydrodynamics (SPH) framework is developed. The concrete meso-models under different pre-existing micro-fissure inclinations and bridge angles (the inner tip line of the double pre-existing micro-fissure is defined as a bridge, and the angle between the bridge and the horizontal direction is defined as the bridge angle) were established, and numerical simulations of the crack propagation processes of concrete structures under tensile stress were carried out. The main findings were as follows: The concrete meso-structures and the pre-existing micro-fissures all have great impacts on the final failure modes of concrete. The stress–strain curve of the concrete model presents four typical stages. Finally, the crack initiation and propagation mechanisms of fissured concrete are discussed, and the application of smoothed particle hydrodynamics (SPH) in crack simulations of fissured concrete is prospected.

This research utilised an open-sourced smoothed particle hydrodynamics (SPH) tool to model and predict the change in wave-induced forces and motions of a free-floating bergy bits approaching a fixed structure in regular waves. Simulation parameters, including particle resolution, fluid viscosity, initial wave condition and boundary treatments, are varied, and their effect on the load imparted to the bergy bit and the structure are investigated. The predicted motions are compared with previously published physical measurements for corresponding scenarios. Both predictions and measurements showed that, in regular waves, the surge motion slowed as the bergy bit approached the structure, and the heave motion increased. For wave loading on bergy bits, the agreement with the experimental data for the root mean square (RMS) force was within 2%. The pressure and velocity fields of the wave–structure–bergy bit interactions are discussed in light of the SPH predictions. This work confirms that the SPH model can accurately capture viscosity–dominated interactions, hydrodynamic damping, and eccentric impact like phenomena and predict both the impact and hydrodynamic loads due to a bergy bit drifting in waves towards a fixed offshore structure.