Numerical Simulation Software Research Articles

Study on blasting fragmentation mechanism of burnt rock in open-pit coal mine

A large number of burnt rocks in some open-pit mines in Xinjiang, Inner Mongolia and Ningxia have a great influence on the blasting effect. For this kind of rock, through the analysis of physical and chemical changes, combined with ANSYS/LS-DYNA and PFC 2D numerical simulation software, a burnt rock model with multiple joint cracks and irregular distribution is constructed to simulate the blasting process of burnt rock under the combined action of stress wave and detonation gas. The results show that the fracture of rock mass affects the propagation of blasting cracks in the fracture area, resulting in stress concentration and stress hindrance. The action time of stress wave is reduced, and the energy of blasting gas is partially absorbed by the fracture, resulting in uneven stress on the burnt rock bench and seriously affecting the bench blasting effect.

An analytical subthreshold I–V model of SiC MOSFETs

In this article, an analytical I–V model for calculating subthreshold current of SiC MOSFETs is presented. This model starts with planar MOSFETs and utilizes the one-dimensional Poisson’s equation to derive an analytical expression for the surface potential. Subsequently, it employs this expression as a foundation for subthreshold current calculations. Then the model is extended to DMOSFETs based on the fact that channel current formation mechanism of DMOSFETs is similar to that of planar MOSFETs. Comparative analysis of our model calculations with two-dimensional numerical simulation software reveals that our model exhibits a high degree of agreement in the case of planar MOSFETs and DMOSFETs. Interface traps were also considered in our analytical model, which agrees well with experimental data published elsewhere. Furthermore, the model retains a certain degree of accuracy and predictive capability even in the presence of short-channel effect. Our subthreshold model becomes complementary to existing models which only describe the I–V characteristics of SiC MOSFETs when the transistors operate above the threshold voltages.

Research on the Failure Mechanism of Surrounding Rock in a Dynamic Pressure Roadway and Active and Passive Coordinated Support Technology

To study the phenomenon of large deformation and the failure of roadways under dynamic pressure, this paper takes the 10607 gas drainage roadway as the research object and presents the results of a theoretical derivation of equations for the boundary of the plastic zone of a dynamic pressure roadway with and without supporting force. The impacts of the mining influence coefficient and supporting force on the plastic zone boundary were explored for various lateral pressure coefficients. As the supporting force was increased, it was observed that there was a slight reduction in the radius of the plastic zone of the dynamic pressure roadway, while its scope and shape barely changed. Based on the failure mechanism of the dynamic pressure roadway, active and passive support technology was proposed, and the support effect was analyzed using FLAC3D 5.0 numerical simulation software for the case of the 10607 gas drainage roadway.

Simulation of Temperature Field in Railway Embankment Filling in Seasonal Frozen Areas

In order to examine the temperature field changes of railway roadbed in seasonal frozen areas under different filling heights, a typical cross-sectional model of Chagan Lake Station railway was established using the finite element numerical simulation software ANSYS. The temperature parameters of the roadbed were calculated based on the atmospheric temperature of local meteorological data, and the temperature fitting curve was used as the temperature boundary condition. Under different filling quantities, the temperature field of the roadbed was simulated for a freeze-thaw cycle, and the temperature curve changes were analyzed. The results indicate that as the filling height increases, the freezing depth line also increases accordingly. When the filling height is 2.5m, the maximum freezing depth at the roadbed is 1.7m. In a freeze-thaw cycle, the freezing process of soil develops from top to bottom, and the melting process develops in two directions: from top to bottom and from a certain depth of soil upwards, with the characteristics of "unidirectional freezing and bidirectional melting". The freezing period starts from early December of each year to the end of March of the following year, and completely melts until the end of April. Melting develops faster than freezing.

Effect of Multiple Factors for the Roadway Excavation Process Stability in FLAC3D

Abstract Appropriate simulation set parameters are the precondition to obtain accurate results; while the simulation results are affected by multiple factors, it is thus crucial to investigate the sensibility of different factors. This paper first analyses the application situation of numerical simulation software in the field of geotechnical engineering and finds that Fast Lagrangian analysis of continua in three dimensions (FLAC3D) has been widely used on roadways or tunnels. Then, taking the roadway excavation process as the engineering background, FLAC3D was used to create 171 schemes of different simulation parameters and analyze the influence of different factors on the simulation results. The findings show that there is a considerable difference in the degree of effect of different parameters on the simulation results. Most of the factors have a remarkable effect on the numerical simulation results (displacement and stress), and only some factors (parameter uniformity and density) have almost no effect on the results. Meanwhile, the trend of displacement and stress is opposite in most cases. In addition, some neglected factors can also have a considerable effect on the simulation results, such as the zone amount; therefore, it is necessary to avoid the variation of nonstudy factors as possible when carrying out the numerical simulation. This study may significantly assist concerned engineers and technicians in developing a more organized and thorough grasp of the impacts of various parameters on simulation outcomes.

Analysis and experimental research on the reliability of the connection between large-diameter bridge piles and caps

This article investigated the construction conditions of the pile foundation in the Wuxing section of the “Shanghai Suzhou Huzhou” railway bridge project. To test the reliability of large diameter connectors, it has established a finite element model with ABAQUS software for numerical simulation. Based on on-site tests, the reliability of the connection between the pipe pile and the cover steel was studied. According to the simulation results, when the load is P= 900 kN, the displacements of A2 and A3 steel pipe piles are 55.8 mm and 60.1 mm, respectively. The load-displacement relationship shows a high-order curve distribution. According to the results of on-site experiments, the displacements are 77.9 mm and 60.2 mm, respectively. The load-displacement relationship is linear. The results for the simulation and on-site testing are consistent. This study provides a basis to the research on the reliability of the connection between large-diameter steel pipe piles.

Simulation of Gas Fracturing in Reservoirs Based on a Coupled Thermo-Hydro-Mechanical-Damage Model

Gas fracturing technology for enhancing rock permeability is an area with considerable potential for development. However, the complexity and variability of underground conditions mean that a variety of rock physical parameters can affect the outcome of gas fracturing, with temperature being a critical factor that cannot be overlooked. The presence of a temperature field adds further complexity to the process of gas-induced rock fracturing. To explore the effects of temperature fields on gas fracturing technology, this paper employs numerical simulation software to model the extraction of shale gas under different temperature conditions using gas fracturing techniques. The computer simulations monitor variations in the mechanical characteristics of rocks during the process of gas fracturing. This analysis is performed both prior to and following the implementation of a temperature field. The results demonstrate that gas fracturing technology significantly improves rock permeability; temperature has an impact on the effectiveness of gas fracturing, with appropriately high temperatures capable of enhancing the fracturing effect. The temperature distribution plays a crucial role in influencing the results of gas fracturing. When the temperature is low, the fracturing effect is diminished, resulting in a lower efficiency of shale gas extraction. Conversely, when the temperature is high, the fracturing effect is more pronounced, leading to a higher shale gas production efficiency. Optimal temperatures can enhance the efficacy of gas fracturing and consequently boost the efficiency of shale gas extraction. Changes in the parameters of the rock have a substantial impact on the efficiency of gas extraction, and selecting suitable rock parameters can enhance the recovery rate of shale gas. This paper, through numerical simulation, investigates the influence of temperature on gas fracturing technology, with the aim of contributing to its improved application in engineering practices.

Dynamics analysis and optimal control study of uncertain information dissemination model triggered after major emergencies

In order to effectively prevent and combat online public opinion crises triggered by major emergencies, this paper explores the dissemination mechanism of uncertain information on online social platforms. According to the decision-making behavior of netizens after receiving uncertain information, they are divided into eight categories. Considering that there will be a portion of netizens who clarify uncertain information after receiving it, this paper proposes a SEFTFbTbMR model of uncertain information clarification behavior. The propagation dynamics equations of the model are given based on the theory of differential equations, the basic regeneration number R0 of the model is calculated, and the existence and stability of the equilibrium point of the model are analyzed. The theoretical analysis of the model is validated using numerical simulation software, and sensitivity analysis is performed on the parameters related to R0. In order to reduce the influence caused by uncertain information, the optimal control strategy of the model is proposed using the Hamiltonian function. It is found that the dissemination of uncertain information among netizens can be suppressed by strengthening the regulation of social platforms, improving netizens’ awareness of identifying the authenticity of information, and encouraging netizens to participate in the clarification of uncertain information. The results of this work can provide a theoretical basis for future research on the uncertain information dissemination mechanism triggered by major emergencies. In addition, the results can also provide methodological support for the relevant government departments to reduce the adverse effects caused by uncertain information in the future.

Heterogeneous ensemble prediction model of CO emission concentration in municipal solid waste incineration process using virtual data and real data hybrid-driven

Carbon monoxide (CO) is a hazardous gas discharged during municipal solid waste incineration (MSWI). Its emission concentration serves as a vital indicator for assessing the stability of the MSWI process. Therefore, accurate prediction of CO emissions is crucial. While existing research predominantly relies on historical real data-driven models, it often overlooks the effective utilization of the combustion mechanism. This article introduced a novel approach: a heterogeneous ensemble prediction model that integrates virtual and real data. Firstly, virtual mechanism data was obtained through a multi-condition mechanism model constructed using coupled numerical simulation software of FLIC and Aspen Plus. Secondly, based on this virtual mechanism data, a linear regression decision tree (LRDT) algorithm was employed to establish the mechanism mapping model. Simultaneously, a real historical data-driven model based on a long short-term memory (LSTM) neural network algorithm was developed. In the offline training verification phase, the heterogeneous models were combined using an inequality-constrained random weighted neural network (CIRWNN) after aligning virtual and real samples representing operating conditions based on the k-nearest neighbor (KNN) approach. Subsequently, in the online testing verification stage, CO online prediction was achieved by ensemble the LRDT-based mechanism mapping model and.the LSTM-based historical data-driven model. The proposed method's effectiveness and rationality were validated through an industrial case study of MSWI process in Beijing.

Performance and Interfacial Microstructure of Al/Steel Joints Welded by Resistance Element Welding.

In this study, an upper sheet of an A6061 aluminum alloy and a lower sheet of Q235 steel were welded by resistance element welding with a steel rivet. The temperature field during welding was calculated using ABAQUS numerical simulation software, and the interfacial microstructure was observed. A nugget was formed between the rivet shank and the lower sheet. With increases in welding current and welding time, the tensile shear load of the joint increased first and then decreased slightly. When the welding current was 14 kA and the welding time was 300 ms, the tensile shear load of the joint reached a maximum of 7.93 kN. The smaller the distance from the position to the lower sheet along the interface between the rivet shank and upper sheet, the longer the high-temperature duration and the higher the peak temperature during welding. At the junction of the rivet shank, upper sheet, and lower sheet in the joint, the high-temperature duration was the longest, at about 392 ms, and the peak temperature was the highest, at about 1237 °C. The results show that the smaller the distance from the position to the lower sheet along the interface between the rivet shank and the upper sheet in the joint, the thicker the reaction layer generated there, and that the thickness of the reaction layer was about 2.0 μm at the junction of the rivet shank, upper sheet, and lower sheet in the joint.

CFD Analysis of Ultra-High-Performance Concrete Rheological Tests

This study connects and compares the results from two different rheological measurement techniques, namely, the slump test and rotational rheometry, on UHPC (Ultra-High-Performance Concrete) through the use of commercially available numerical simulation software ANSYS Fluent 2022 R2. The workability and resulting mechanical properties of the UHPC (a material used in construction) are highly dependent on its rheology and, hence, also on the composition and level of homogeneity of the assessed mixture. It is generally understood that the most suitable rheological model for concrete mixtures is the Hershel–Bulkley model. However, obtaining reliable rheological data is complicated as the wide-gap rotational rheometers developed for concrete show bias in their measurements even on precise laboratory equipment, while common industrial tests, such as the slump test, do not produce the usual shear rate–shear stress relation and, hence, do not allow for more complex analysis. Recently, a new methodology for the rheological measurement of non-Newtonian fluids that utilises a simple power input–rotation speed measurement was published. However, in this study, only model liquids were evaluated, and the method was not validated for more complex fluids such as pastes. Therefore, it was the goal of this study to show this method’s suitability for fine pastes through a comparison with the slump test, using numerical simulation.

Optimization Analysis of Partition Wall Support Scheme of Multi-Arch Tunnel

With the fast progress of infrastructure projects, super-large cross-section projects are constantly emerging, and, therefore, engineering challenges and problems are increasing. Taking the triple-arch tunnel project in the turn-back line section of Santunbei Station in Urumqi Metro Line 1# as a case study, this research applied numerical simulation software Midas GTS/NX 2022 for the analysis of tunnel force and deformation in triple-arch cross-sections under different support forms of partition wall. Following the optimization of the support design of the mixed partition wall to a single straight wall, the following analytical results were obtained: surface settlement was decreased by 21.15% at the original cross-section; maximum values of principal stress and displacement of partition wall were decreased by 6.73 and 10.64%, respectively; and corresponding values for initial support structure were decreased by 21.47% and 54.74%, respectively. Meanwhile, combined with comparative analysis of engineering measurement and numerical simulation results, surface settlement and vault deformation were found to be similar to the optimized simulation results, which not only verified the reliability of simulation results but also ensured the safe and smooth construction of the project, greatly improving construction efficiency and saving construction time and cost.

Research on the Reinforcement Effect and Bearing Characteristics of High-Pressure Jet-Grouting Piles on Covered Road Composite Ground in Landfill Sites

There is a notable difference between garbage pile foundations and general site foundations; due to their uneven particles, complex structure, and diverse composition, there are relatively few cases that can be used for reference. In this study, with the aim of renovating a landfill in Shenzhen, bearing-layer reinforcements were introduced in the overlying road of a garbage heap dominated by construction waste. The bearing capacity of a single-pile composite foundation was studied through a core-pulling test of high-pressure jet-grouting piles, a static load test of the bearing capacity of the single-pile composite foundation, design estimation, and numerical analysis. The results show that the obtained eigenvalue of the design estimate was 267.8 kPa, and the eigenvalue of the field test was between 182.58 kPa and 196.89 kPa, meeting the design requirement of an eigenvalue of no less than 175 kPa. The bearing capacity of the composite foundation of the single jet-grouting pile was analyzed using the ABAQUS numerical simulation software; the characteristic value of the bearing capacity of the single-pile composite foundation was 186.01 kPa, and the variation trend of its settlement–load curve was the same as that of the field test results, which met the design requirements. High-pressure jet-grouting pile technology has achieved remarkable results in the reinforcement of foundations that are mainly composed of construction waste.

Numerical study on the tensile properties of a cylindrical specimen with chopped basalt fibre thermosetting resin matrix composites

For several decades, the disadvantages of traditional metallic rock and soil support structures have become increasingly prominent. As a result, it is urgent to seek lightweight, high-strength, durable and green economic substitute products made from the basalt fibre reinforced composites. Combining the two-phase material summing principle of composite material mechanics and the extension and application of Mohr–Coulomb strength criterion, the uniaxial tensile computing model of a cylindrical polymer specimen containing randomly distributed and discontinuous basalt fibres was established in accordance with the numerical simulation software Flac3D. Furthermore, the influence laws and intrinsic mechanism of the number of discrete fibres and different fibre distribution angles on the integral axial tensile properties of a cylindrical specimen with chopped basalt fibre thermosetting resin matrix composites were investigated and elucidated, and the stress–strain curve of basalt fibre thermosetting resin matrix composites were obtained. Consequently, the results have indicated that: i) the axial tensile strength of the polymer system can be enhanced through the incorporation of a moderate quantity of chopped fibres, with the resultant improvement typically not surpassing a 10% increment; ii) when the number of fibres has increased to the quantitative state, namely, the fibre density reaches 1.02 pieces/cm3 or more, the amplification of axial tensile strength of composite material will be controlled; iii) the fibre distribution directions, are maintaining a 0° parallel state to the axial direction of the specimen and the ones of load application, will ensure that the tensile strength of the composite can be sufficiently utilized. As the production process within the composite industry have become increasingly adept, the research results hold substantial value for further promoting the development, testing and optimizing application of various types of high-performance basalt fibre reinforced composite products.

Evolutionary game analysis of carbon emission reduction of Internet enterprises under multiple constraints.

With the rapid development of information technology, internet enterprises have sprung up, bringing about huge power consumption due to constantly expanding enterprise scale, which in turn leads to significant carbon emissions. Additionally, the large influence of internet enterprises on the public and other businesses makes it particularly necessary to pay attention to their carbon emission reduction efforts. To explore the evolution path and patterns of carbon emission reduction among internet enterprises under the carbon neutrality goal, this paper constructs an evolutionary game model for internet enterprises to enter the carbon emissions trading market based on Externality and Sustainable Development Theories, while considering constraints from the carbon market, financial institutions and the public. The model utilizes Python 3.8.2 software for numerical simulations, aiming to push internet enterprises towards low-carbon development. The research findings indicate that: (1) Carbon emission reduction behavior of internet enterprises exhibits significant externality, and when constraints are weak or incentives are not evident, the motivation for enterprises to reduce carbon emissions is insufficient. (2) The carbon market can effectively promote carbon emission reduction among internet enterprises, and the strategy of entering the carbon market becomes the preferred option for these enterprises gradually. (3) Multiple constraints, including emission reduction costs, penalty for non-compliance, government subsidies, financing costs, opportunity losses, and reputation losses, can force internet enterprises towards low-carbon development.

Semi-Analytical Reservoir Modeling of Non-Linear Gas Diffusion with Gas Desorption Applied to the Horn River Basin Shale Gas Play, British Columbia (Canada)

Adsorbed gas may account for a significant part of the gas resources in shale gas and coalbed methane plays. Understanding gas sorption behaviors and integrating gas desorption into analytical reservoir modeling and an associated transient performance analysis are important for evaluating a system’s gas desorption ability and further analyzing its CO2 injectability, utilization, and storage capacity. However, gas desorption, along with other pressure-dominated gas properties, increases a system’s non-linearity in theoretical studies. Few studies on analytical modeling have integrated the gas desorption feature into a non-linear system and validated the model’s accuracy. In this study, the desorbed gas due to pressure decay was treated as an additional source/sink term in the source-and-sink function methods. This method was combined with the integral image method in a semi-analytical manner to determine the amount of gas desorption. Fundamental reservoir and gas properties from the Horn River Basin shale gas play were chosen to evaluate the methodology and the performance of the associated production well. The results were compared with the commercial fine-gridding numerical simulation software, and good matches were achieved. The results showed that the desorbed gas released from rock will supply free-gas flow when the pressure significantly decreases due to gas production. The production wellbore pressure can be maintained at a higher level, and the production rate was higher than in cases where gas desorption was not considered, depending on the operating conditions.

The mechanical characteristics and cooling performance of a turbine blade with non-homogeneous lattice structure

The turbine blade is working at a high rotation speed and under constant impact from the high-temperature and high-pressure mainstream, causing deformation and a reduction in working efficiency; at the same time, the mainstream temperature at the inlet is increasing to achieve a high heat efficiency. Therefore, there is a high demand for turbine blade cooling technology. In this study, the authors proposed replacing the traditional spoiler with a non-homogeneous lattice structure in the inner cavity of the high-pressure turbine blade. The turbine blade was then simulated and experimend in real-world conditions using numerical simulation software and manufactured actual blades, and the maximum deformation of the turbine blade was measured to assess the impact of the non-homogeneous lattice structure on the blade's strength. The findings are as follows: The maximum deformation of the turbine blade optimized with a non-homogeneous lattice structure is 9.91% less than that of the traditional turbine blade with a spoiler, and its deformation-weight ratio is 11.51% less than the latter; the optimized turbine blade has a large cooling area in the concave surface of the blade, which improves the air film cooling effect, the coverage area of gas film hole outlet flow rate has increased by 12.39%. Finally, the non-homogeneous lattice structure optimizes the inner cavity structure of the turbine blade and is useful for improving the turbine blade's structural design and air film cooling performance.

GFNS: An OpenGL-based tool for shield tunneling simulation in 3D complex stratum

Shield tunneling under complex geological conditions may lead to uneven surface settlement, thereby posing risks of damaging adjacent structures. This paper introduces the Geological Model for Numerical Simulation (GFNS) software, which employs OpenGL to implement a 3D geological model. The software incorporates an advanced geological stratum meshing algorithm based on conditional statements, facilitating the swift construction of numerical models for shield tunneling in intricate geological formations. In this study, a numerical model for shield tunneling in complex geological conditions was developed using GFNS. The research investigated potential risk levels to adjacent structures due to shield tunneling through alternating soft and hard geological strata along the tunnel's longitudinal axis. Moreover, the influence of shield excavation position and construction parameters on surface settlement was analyzed. Finally, a comparison was conducted with the traditional parallel geological modeling approach. The results revealed that simulating shield tunneling while considering complex geological conditions demonstrates a stronger correlation with the laws of stratum settlement. Thus, GFNS offers an auxiliary modeling method for simulating shield tunneling under complex geological conditions.

Development of a Silicone Rubber Mold with an Innovative Waterfall Cooling Channel.

A conformal cooling channel (CCC) follows the mold core or cavity profile to carry out uniform cooling in the cooling stage. However, the significant pressure drop along the cooling channels is a distinct disadvantage of the CCC. In this study, an innovative waterfall cooling channel (WCC) was proposed and implemented. The WCC cools the injected products via surface contact, replacing the conventional line contact to cool the injected products. The WCC was optimized using numerical simulation software. Silicone rubber molds with two kinds of cooling channels were designed and implemented. The cooling time of the molded part was evaluated using a low-pressure wax injection molding machine. The experimental results of the cooling time of the molded part were compared with the simulation results from numerical simulation software. The results showed that the optimal mesh element count was about 1,550,000 with a mesh size of 1 mm. The simulation software predicted the filling time of the water cup injection-molded product to be approximately 2.008 s. The cooling efficiency for a silicone rubber mold with a WCC is better than that of the silicone rubber mold with a CCC since the core and cavity cooling efficiency is close to 50%. The pressure drop of the WCC is smaller than that of the CCC, which reduces the pressure drop by about 56%. Taking a water cup with a mouth diameter of 70 mm, a height of 60 mm, and a thickness of 2 mm as an example, the experimental results confirmed that the use of the WCC can save the cooling time of the product by about 265 s compared with the CCC. This shows how a WCC can increase cooling efficiency by approximately 17.47%.

Effects of multiple hydraulic punching for ultra-deep buried high ground stress powdered coal seam with low permeability

The high ground stress and poor gas permeability of the ultra-deep buried highland stress coal seam make it difficult for conventional unloading and permeability-increasing techniques, such as fracturing or cutting, to achieve the goal of coal seam pressure relief. This article proposes a multi-stage hydraulic punching permeability increasing scheme for the M1-7∼M1-9 gas drainage project of the powdered coal seam with highland stress (44.42 MPa) in tunnel No. 2 of Zhaotong, and studies the effect of cavity formation and gas changes caused by multiple hydraulic punching through theoretical analysis and numerical simulation methods. The gas drainage effect after multiple hydraulic punching was also monitored on-site and systematically compared with natural gas drainage and single hydraulic punching permeability-increasing techniques to determine the optimal solution for multi-stage hydraulic punching. Using the COMSOL numerical simulation software, a coal body model was established based on theoretical analysis. Boundary pressures, ideal gas pressures, and high-pressure water flow pressures were set as boundary conditions to simulate the process of hydraulic punching. The theoretical analysis and numerical simulation were then used to guide on-site experiments. The research results shows that for ultra-deep buried highland stress powdered coal seams, natural gas drainage efficiency is extremely low, and the initial effect of single hydraulic punching permeability increasing is significant, but the fast decay rate of short gas is still due to the time that the cavity formed by hydraulic punching exists. Multiple hydraulic punching effectively alleviates the gas decay rate, and the gas drainage efficiency can reach three times and 22 times that of single hydraulic punching and natural drainage techniques, respectively. When the hydraulic punching interval period is five days and the hydraulic punching frequency is three times, the gas drainage effect is optimal. Multiple hydraulic punching permeability-increasing technologies can provide reference for gas extraction in similar low permeability coal seams with highland stress. The research holds great significance in promoting efficient gas extraction and ensuring the safety construction of gas tunnels.