Field Analysis Method Research Articles

Experimental investigation on in-situ laser-assisted machining of single crystal silicon based on response surface methodology

Abstract In this paper, Response Surface Methodology (RSM) was utilized as a robust and convenient predictive tool to establish the correlation between process parameters in in situ laser-assisted machining and the surface roughness of single-crystal silicon. An optimized design of the diamond tool, a novel temperature field analysis method, and Response Surface Methodology (RSM) were utilized. The contribution rate of each process parameter on surface roughness was laser power > rotation speed > cutting depth > feed rate. The optimal process parameter combination is: rotation speed as 1001 r min−1, feed rate as 4.9 μm/r, cutting depth as 7.55 μm, and laser power as 28.81 W. Experimental validation of these optimal parameters compared surface roughness values obtained experimentally with those predicted. The surface roughness model showed a maximum relative error of 5.2%, with an average error of 4.8% across three experimental sets. These errors are within acceptable limits, indicating an alignment between predicted and experimental results.

Study on suction effect of water jet propulsion pump based on entropy weight theory

Water jet propulsion pumps start at special stages such as mooring and sailing, the ship is in shallow water, and the underwater keen clearance (UKC) is relatively small, which is easy to induce underwater suction vortex near the inlet position and cause violent vibration of the pumping unit. The powerful suction effect of the water-jet propulsion pump can draw in debris from the bottom of the riverbed, causing damage to the propulsion pump. This research investigated the suction effect of water jet propulsion pump under different UKC conditions. A flow field analysis method based on the entropy weight theory was constructed to reveal the flow characteristics of the flow field where the underwater suction vortex occurs. The research found that the suction effect on the flow field tends to stabilize under the condition of UKC greater than 2.5D0. After UKC reaches 4.2D0, suction effects essentially cease to create large-scale shear stresses near the riverbed. In addition, this research analyzes the vorticity field using vorticity and net circulation to elucidate the vortex strength within the flow field under different UKC conditions. The probability of generation of underwater suction vortices will be greatly reduced when the UKC is greater than 0.83D0.

Research on optimum design and control of permanent magnet synchronous motor for elevator

Abstract Due to the impact of the world energy crisis and environmental pollution problems, the combination of frequency converter and permanent magnet synchronous motor (PMSM) as the core of elevator drive has become a new direction for the development of the elevator industry. Compared with the traditional electric excitation synchronous motor, because the rotor of PMSM adopts permanent magnet excitation, no excitation winding, brush and slip ring are needed, the motor volume is greatly reduced. At the same time, for there is no excitation loss, the efficiency of PMSM) is higher than that of electric excitation synchronous motor. Therefore, the application of PMSM in elevator drive system has more obvious advantages. In this paper, PMSM for elevator is taken as the research object, and motor design software Motor-CAD is used to optimize the design of a kind of PMSM with power level. Then, the fine-tuned and optimized model is imported into the finite element analysis software, and the magnetic field analysis method is used to simulate the electromagnetic field of PMSM, so as to observe the magnetic field distribution of PMSM in the static field. At the same time, the three phase EMF and current waveform of PMSM is analysed to verify the design meets the requirements. Finally, the cogging torque of PMSM is studied in detail. Because the stator fractional slot winding design is adopted, the cogging torque of the prototype is greatly reduced.

Improved GAN-based deep learning approach for strain field prediction and failure analysis of precast bridge slab joints

Nonlinear finite element analysis (FEA) is crucial for understanding complex stress-strain behaviors and assessing potential structural failure risks. Building on the recent success of deep learning (DL) methods in physical field predictions, there has been growing interest in forecasting internal force fields of structures beyond the existing data scope. In this study, a data-driven strain field analysis model based on an improved Generative Adversarial Network (GAN) is proposed. To enrich the input data, this novel approach incorporates the Signed Distance Field (SDF) derived from the characteristics of the original Finite Element (FE) models. The generator, based on U-Net, is enhanced with channel attention mechanisms and loss penalty terms, forming the core of the improved GAN. The effectiveness of the proposed method is demonstrated using two parallel datasets comprising 3-Headed bar tension models across two planes. Subsequently, the generated strain field is subjected to feature extraction using the 2D-Principal Component Analysis (2D-PCA) method, followed by structural failure determination through the K-Nearest Neighbor (KNN) algorithm. The results indicate that the proposed improved approach achieves a significant reduction in Root Mean Square Error (RMSE) of 20.71 % and 13.21 % across the two datasets, with the structural failure determination method reaching an F1-score of 0.971. Thus, the intelligent strain field analysis method introduced here effectively predicts strain distributions and promptly identifies failure states, offering valuable insights for further numerical analysis and structural design.

A real-time temperature field prediction method for steel rolling heating furnaces based on graph neural networks

In the billet reheating process during steel rolling, the real-time and accurate prediction of the temperature field is a prerequisite for the dynamic regulation of the heating process, which is crucial for ensuring the quality of billet reheating and reducing the energy consumption of the reheating furnace. The most commonly used finite element thermal field simulation and analysis methods are unable to meet the demand for real-time prediction under dynamic working conditions. Furthermore, traditional machine learning methods struggle to handle irregular data that includes spatial location information, resulting in inaccurate temperature field predictions, which in turn affect the furnace control efficiency and the quality of the product. In light of these limitations, this study proposes a Graph Neural Network (GNN)-based temperature field prediction method for steel rolling reheating furnaces. This method considers the interactions between the nodes within the reheating furnace and constructs a temperature field topology graph to effectively capture these interactions, including heat conduction and convection. Additionally, in the feature fusion and state updating mechanism of the model, we introduce process parameters, such as the air-fuel ratio, as additional inputs to enhance the ability of the GNN to handle complex variables. This enables real-time accurate simulation of the internal temperature distribution of the reheating furnace. The experimental results demonstrate that the model prediction error is controlled within 2.9 % and the response time is maintained within 20 ms, thereby validating the reliability and efficacy of the method in practical applications.

Speciation analysis of Sb(III) and Sb(V) by hydride generation-smartphone colorimetric system using metal organic framework as substrate

A portable and easy-use analytical system was established for speciation analysis of inorganic antimony (Sb(III) and Sb(V)) based on hydride generation-smartphone colorimetric method. Metal organic framework (Ag-MOF) was served as substrate here. Sb(III) was transformed to stibine (SbH3) during hydride generation process, SbH3 was then transported and reacted with Ag-MOF in reaction bottle, leading to its color turn to black from light gray, the variance was then distinguished by visual and smartphone mode. A detectable limit as low as 0.01 μg/mL can be readout by smartphone mode. Besides, citric acid was used as masking reagent for speciation analysis of Sb(III) and Sb(V). Several real environmental water samples were further detected using this colorimetric system and recoveries for those samples were 90–106 %. The potential application of this method for rapid and field analysis of inorganic antimony was further demonstrated by analysis of a certified reference water sample (BWZ6657-2016B).

3D deformation velocity field analysis and TEM method to detect the tectonic influence on the land subsidence in Zamora, Mexico

The city of Zamora is situated in a tectonic basin and, according to previous interferometric studies, has been experiencing sinking up to 13 cm/yr (2007-2011). Although the reported subsidence pattern (WNW-ESE) is similar to the orientation of the regional fault system, there is a lack of detailed studies to establish the connection between this phenomenon, the thickness of sediments, and the basement geometry. Therefore, this paper presents a 3D deformation velocity field analysis for the period of 2014–2021, using 130 images from the Sentinel-2 satellite to calculate the vertical and east-west components of the subsidence. Likewise, a campaign of 28 Transient Electromagnetic soundings was carried out around the city to determine the thickness of sediments and bedrock geometry. The results of the interferometric analysis reveal a WNW-ESE sinking pattern with the maximum vertical velocities observed near the Zamora Museum, amounting to 108 mm/yr (2014–2017) and 102 mm/yr (2018–2021). Meanwhile, the horizontal component has a heterogeneous behavior in both periods with rates reaching up to 1 cm/year. The Transient Electromagnetic survey results show the presence of two grabens, a horst, and a series of half-grabens. The thickness of sediments varies between 94 and 314 m, with the latter corresponding to the main graben located beneath the city. The axis of this structure and the largest sediment deposits are linked to the area of maximum sinking and the spatial pattern of subsidence.

Pitch Registration and Harmonic Fields in Works of Pierre Boulez, Marco Stroppa, and Yukiko Watanabe

This paper discusses a method for harmonic field analysis of serial and post-serial music. The method is informed by perception-oriented considerations and was specifically designed for an analysis of Pierre Boulez’s early serial music. It is therefore exemplified by his 1951 composition Polyphonie X. Harmonic field analysis can however be applied to any music where pitch registration plays an important role. Accordingly, I will provide a brief overview of harmonic relations in two more recent compositions by Marco Stroppa and Yukiko Watanabe, demonstrating that harmonic fields have been used by composers to mediate between the generative layers of pitch organization and the sounding surface.

A fully synthetic three-dimensional human cerebrovascular model based on histological characteristics to investigate the hemodynamic fingerprint of the layer BOLD fMRI signal formation.

Recent advances in functional magnetic resonance imaging (fMRI) at ultra-high field (≥7 tesla), novel hardware, and data analysis methods have enabled detailed research on neurovascular function, such as cortical layer-specific activity, in both human and nonhuman species. A widely used fMRI technique relies on the blood oxygen level-dependent (BOLD) signal. BOLD fMRI offers insights into brain function by measuring local changes in cerebral blood volume, cerebral blood flow, and oxygen metabolism induced by increased neuronal activity. Despite its potential, interpreting BOLD fMRI data is challenging as it is only an indirect measurement of neuronal activity. Computational modeling can help interpret BOLD data by simulating the BOLD signal formation. Current developments have focused on realistic 3D vascular models based on rodent data to understand the spatial and temporal BOLD characteristics. While such rodent-based vascular models highlight the impact of the angioarchitecture on the BOLD signal amplitude, anatomical differences between the rodent and human vasculature necessitate the development of human-specific models. Therefore, a computational framework integrating human cortical vasculature, hemodynamic changes, and biophysical properties is essential. Here, we present a novel computational approach: a three-dimensional VAscular MOdel based on Statistics (3D VAMOS), enabling the investigation of the hemodynamic fingerprint of the BOLD signal within a model encompassing a fully synthetic human 3D cortical vasculature and hemodynamics. Our algorithm generates microvascular and macrovascular architectures based on morphological and topological features from the literature on human cortical vasculature. By simulating specific oxygen saturation states and biophysical interactions, our framework characterizes the intravascular and extravascular signal contributions across cortical depth and voxel-wise levels for gradient-echo and spin-echo readouts. Thereby, the 3D VAMOS computational framework demonstrates that using human characteristics significantly affects the BOLD fingerprint, making it an essential step in understanding the fundamental underpinnings of layer-specific fMRI experiments.

Research on the calculation method of grinding temperature field of spiral bevel gear based on generative machining

At present, the process parameter setting of spiral bevel gear grinding is mainly based on an empirical method, and the tooth surface temperature is difficult to estimate effectively during grinding, which may lead to excessive tooth surface temperature and surface burn caused by improper selection of process parameters. Aiming at the above problems, this paper presents a method for calculating the temperature field of spiral bevel gear forming based on a combination of analytical and numerical methods. The motion equation of spiral bevel gear grinding is derived based on the method of tooth surface development. The time-varying heat flow calculation method in tooth surface grinding was developed through the discrete and two-dimensional contact zone. The time-varying temperature field analysis method of spiral bevel gear forming is developed using the time-varying heat flow and finite element calculation method. The related research can realize the temperature prediction of grinding tooth surfaces and provide the basis for improving grinding technology.

Modelling permanent magnet excited uniform fields with rational approximations

PurposeA novel method for modelling permanent magnets is investigated based on numerical approximations with rational functions. This study aims to introduce the AAA algorithm and other recently developed, cutting-edge mathematical tools, which provide outstandingly fast and accurate numerical computation of potentials and vector fields.Design/methodology/approachFirst, the AAA algorithm is briefly introduced along with its main variants and other advanced mathematical tools involved in the modelling. Then, the analysis of a circular Halbach array with a one-pole pair is carried out by means of the AAA-least squares method, focusing on vector potential and flux density in the bore and validating results by means of classic finite element software. Finally, the investigation is completed by a finite difference analysis.FindingsAAA methods for field analysis prove to be strikingly fast and accurate. Results are in excellent agreement with those provided by the finite element model, and the very good agreement with those from finite differences suggests future improvements. They are also easy programming; the MATLAB code is less than 200 lines. This indicates they can provide an effective tool for rapid analysis.Research limitations/implicationsAAA methods in magnetostatics are novel, but their extension to analogous physical problems seems straightforward. Being a meshless method, it is unlikely that local non-linearities can be considered. An aspect of particular interest, left for future research, is the capability of handling inhomogeneous domains, i.e. solving general interface problems.Originality/valueThe authors use cutting-edge mathematical tools for the modelling of complex physical objects in magnetostatics.

Temperature field analysis and equal-amplitude temperature rise constraint current control method under open-circuit fault-tolerant operation for five-phase permanent magnet motor

The phase redundancy and freedom of the five-phase permanent magnet motor (FPPMM) enhance the reliability of the motor system. However, the temperature rise and torque reduction issues of the motor during open-circuit fault operation need to be further studied. In order to study the temperature distribution characteristics and the output capability of the motor under fault operation subject to temperature rise constraints, a 3-D global temperature field model containing a complex heat dissipation structure has been established. And the equal-amplitude temperature rise constraint current control method is proposed under open-circuit fault-tolerant operation to improve its output capability. The temperature distribution of the motor during steady state operation under rated operating conditions is analyzed with emphasis. Based on this, the temperature field changes of the motor during single-phase and two-phase open-circuit fault-tolerant operation are investigated. Then, the proposed equal-amplitude temperature rise constrained current method is introduced in detail to ensure the safe operation of the motor. An experimental platform is built, which verifies the accuracy of the temperature field calculation, as well as the correctness of equal-amplitude temperature rise constrained current method.

Study on fire temperature fields of air-supported membrane structures considering thermal–fluid–solid coupling and boundary correction

The study analyzed and compared the effects of thermal–fluid–solid coupling dynamic boundary conditions and traditional fixed-boundary conditions on the distribution of the temperature field under fires. The feasibility of simulating the temperature field distribution was confirmed by using thermal–fluid–solid coupling dynamic boundary conditions. Then, the traditional temperature field analysis methods were corrected by including a flow-based heat exchange coefficient, and the feasibility of this approach was also confirmed. The fire temperature field in a rectangular air-supported membrane structure was analyzed through parameterization. The fire temperature field model of the air-supported membrane structure was established using temperature field data fitting. Furthermore, the study explored the high-temperature material properties of P-type membranes and analyzed and compared the temperature field of the air-supported membrane structure with time-varying mechanical properties of the membrane material to that without time-varying properties.

Motor magnetic field analysis using the edge-based smooth finite element method (ES-FEM)

This paper proposes a smooth finite element method (S-FEM) for efficient and accurate analysis of motor magnetic fields. The edge-based smooth finite element (ES-FEM) formulations are derived for two-dimensional triangular element meshes suitable for multi-material motor structures, and then a magnetic flux density calculation method appropriate for S-FEM to calculate nonlinear electromagnetic fields is introduced. In the calculation of motor magnetic field, ES-FEM has a proper softening effect on the stiffness matrix of the finite elements, which makes the calculation more accurate and more efficient than FEM. The magnetic flux intensity calculation method introduced in this paper is not only appropriate for ES-FEM to calculate the nonlinear electromagnetic field of motor, but also can improve the calculation accuracy of magnetic flux density. In the calculation of nonlinear magnetic field of motor, ES-FEM can also improve the calculation accuracy of magnetic field analysis compared with FEM. Several numerical examples demonstrate the improving effect of the ES-FEM discussed above on the motor's magnetic field calculation.

Dual-stage theoretical model of magnetorheological dampers and experimental verification

The theoretical model for predicting the damping characteristics of magnetorheological dampers (MRDs) not only facilitates the optimization of MRD parameters, but also provides assistance for the theoretical design of MRDs. However, some existing models have limitations in fully characterizing the damping characteristics of MRDs. In this paper, the working stage of MRDs was categorized into yield and pre-yield stages based on whether the internal magnetorheological fluid attains the dynamic shear yield state or not, and the Herschel–Bulkley model with pre-yield viscosity (HBPV) and improved polynomial model (IPOL) were employed to respectively characterize the yield and pre-yield stages of MRDs. Subsequently, the HBPV-IPOL model was proposed to characterize the complete damping characteristics of MRDs in low-frequency vibration conditions, with considering the local loss effect of the fluid in the model. To accurately characterize the magnetic induction intensity in the MRD damping channel, employing the steady-state finite element method for magnetic field analysis; on this basis, dividing the damping channel to investigate the variation trends of the magnetic induction intensity in different regions. Simultaneously, the zero-field region hypothesis was proposed to quantitatively consider the influence of minute magnetic induction intensity in the traditional zero-field regions on the damping characteristics of MRDs. Finally, integrating the impact trends of currents in different regions, and employing the HBPV model to determine the impact magnitude of each region within the damping channel on the damping characteristics of the MRD in the yield stage. In the pre-yield stage, polynomial curves were fitted to experimental damping force–velocity curves, and the obtained polynomials were employed to predict the damping characteristics. Extensive experiments have been conducted on MRD samples to assess the predictive performance of the model on MRD damping characteristics under sinusoidal displacement excitation vibration conditions with different excitation currents, vibration frequencies and vibration amplitudes.

Exploring the Intelligent Emergency Management Mode of Rural Natural Disasters in the Era of Digital Technology

In recent years, rural areas of China have experienced frequent occurrences of various natural disasters. These calamities pose significant threats to the safety, property, and mental well-being of rural residents while also presenting substantial obstacles to the sustainable development of the rural economy. Currently, emergency management in China faces several challenges such as inadequate emergency institutions, insufficient security policies, weak disaster infrastructure, and difficulties in information sharing. In light of this situation, we propose an intelligent command mode based on modern digital technology that capitalizes on its advantages and integrates early warning systems with decision-making processes and rescue operations to establish a comprehensive emergency event processing system. This innovative approach opens up new avenues for exploring and researching effective modes of rural emergency management. The article elaborates on how the construction of a smart rural emergency management mode facilitates the digital integration of disaster elements while enhancing the efficiency of emergency response efforts and promoting sustainable development. The research methodology employed includes literature review methods along with field research techniques and analysis methods. Finally, this discussion evaluates both the benefits and challenges associated with implementing this mode within rural emergency management practices.

Electromagnetic analysis of a wound rotor synchronous machine using an improved subdomain technique considering finite permeability of the core

This study proposed an improved analytical method for electromagnetic field analysis of a wound rotor synchronous machine (WRSM) considering the permeability of soft magnetic materials. A simplified analytical model considering the magnetic permeability of each region is presented. The governing equations of each region are derived from Maxwell’s equations and the electromagnetic field theory, and a general solution is derived by using mathematical techniques. The analytical solutions of all domains are derived by calculating the boundary conditions. To validate the proposed analytical method, the radial and circumferential magnetic flux densities are compared with finite element analysis (FEA) results. In addition, electromagnetic performance parameters such as flux linkage, back-electromotive force, and torque are determined using electromagnetic theories. In particular, the magnetic saturation of the soft magnetic material is due to field and armature current, and the superiority of the proposed method is demonstrated by comparing the improved analytical method considering the global saturation of each region with the nonlinear FEA result considering local saturation. The proposed analytical method can be widely used in the initial and optimal design of WRSM because it can consider saturation of the core due to changes in field and armature current.

Multi-physical Field Analysis Method for Enclosed Isolated Phase Busbar of Hydropower Station

In this paper, geometrical modelling and finite element multi-physical field analysis method are carried out for the actual layout of the enclosed isolated phase busbar (EIPB) of a hydropower station, for the horizontal and vertical connection parts that can hardly be considered in the analytical calculation process. The finite element model is able to accurately represent the main structure of the EIPB by reasonably simplifying some of the components. Meanwhile, the finite element model incorporates the coupling of magnetic field and transient structural field, allowing for analysis of the magnetic field distribution, stress-strain distribution, modal analysis, and harmonic response of each component of the EIPB. It is capable of analyzing the vibration response of the complex horizontal-vertical structure EIPB under different excitations. This method can overcome the limitations of analytical calculation methods in calculating complex structure EIPBs. It can also provide valuable guidance for the structural optimization design of future EIPBs.

Identifying barriers and benefits of shared e-scooters in promoting sustainability in Kuwait using Delphi and Force Field Analysis Methods

People are wasting time during their way to their destination due to traffic jam. Shared electronic scooter is ana alternative transport mode that saves time. This mode of transportation widely spread after COVID-19 pandemic. This research investigates the main opportunities and barriers of adopting this technology in Kuwait from three sides which are social, environmental, economic, and safety aspects taking into consideration the travel behavior and urban infrastructure sides. Experts’ opinions were collected from two rounds of the Delphi questionnaire. The collected data was analyzed using Force Field Analysis Method in order to get a precises prediction of the most significant facilitators and barriers after the period of COVID-19 to figure out the importance of the sustainability of the e-scooters. According to the urban infrastructure side, the e-scooters adoption was favorable from all aspects except the economic aspect. On the other hand, travel behavior was challenging, it was unfavorable form environmental and safety aspects. It’s recommended to regulate more laws that ensure all road users’ safety.

Concentration‐number (C‐N) fractal models reveal the distribution pattern of the elements in ancient nephrite measured by portable X‐ray fluorescence: Based on nephrite objects excavated from different sites in Nanyang, Henan Province

AbstractChanges in the composition of various chemical elements in ancient nephrite artifacts due to prolonged burial are critical factors that should not be underestimated. However, the increasingly stringent heritage management has made many techniques impractical. Consequently, portable X‐ray fluorescence (pXRF) has become an indispensable nondestructive field analysis method. This paper aims to make use of the pXRF dataset to distinguish which elements tested are endogenous or exogenous, as well as to gauge which elements have been affected by stronger burial effects. More specifically, we carry out this work on the example of 103 pieces of nephrite excavated from different cemeteries in the Nanyang area. In addition to traditional statistical techniques, a new tool, the concentration‐number (C‐N) fractal method can shed new light on the analysis of the distribution patterns of different elements in excavated nephrite. The anomalous boundaries generated by the method have clear geochemical significance and can be delineated between background zone and disturbed regions. The degree of resistance of different elements to fluctuations in external factors was assessed, which has a direct relationship with the content of the buried soil. Considering the richness of the model, it has the potential to be used in archaeometrics.