Numerical Calculation Method Research Articles

Modeling and analysis of the equivalent convex mandrel of the three-dimensional braiding carbon fiber composite robotic arm

The third robotic arm (drive housing) of a six-axis industrial robot often has a vertical inwardly concave surface to facilitate the installation of spatially vertical drive motors. With the inwardly concave surface of the robotic arm it is difficult to realize three-dimensional (3D) braiding directly, and based on this problem, an equivalent convex mandrel is added to the concave mandrel. The mathematical model of the concave mandrel is established, and the mathematical expression of the concave mandrel is obtained. In any cross-section perpendicular to the x-axis, the equivalent outwardly convex cross-sectional line is obtained according to the condition that the length of the outwardly convex and concave mandrel cross-sectional line is equal. All outwardly convex cross-sectional lines form a smooth surface of the equivalent convex mandrel. By the numerical calculation method, the braiding trajectory and the downward pressure trajectory are predicted for various take-up speeds. The length error of the braiding trajectory and the downward pressure trajectory are within 5%, which verifies the accuracy of the convex mandrel. The variation pattern of the braiding angle is smooth, verifying the braidability of the convex mandrel. The experimental results show that the outwardly convex carbon fiber fabric can be pressed down to fit the surface of the concave mandrel. Therefore, a carbon fiber composite arm with an inwardly concave surface can be manufactured by 3D braiding with the addition of an equivalent convex mandrel.

Numerical calculation and experimental analysis of thermal environment in industrialized aquaculture facilities.

With the increasing market demand for high-quality aquatic products, the application of industrialized aquaculture facilities may get more attention. In order to improve the poor performance of thermal insulation, the accuracy of the numerical model was verified in this study through actual measured data. The model verification results shown that the average relative errors of the measured and calculated values of indoor air temperature, water temperature and roof inner surface temperature in the industrialized aquaculture workshop is within 2.5%, it suggested that the numerical calculation results are accurate. Furthermore, the thermal environment and thermal insulation performance of industrialized aquaculture facilities in winter were conducted based on the numerical calculations. After optimized the thermophysical parameters of the workshop enclosure structure, we found that the water body temperature could reach 21°C (which was close to the breeding temperature of grouper (Epinephelinae). Therefore, the numerical calculation method was further used to analyze the energy consumption of aquaculture water in January of a typical year in this area by heating to three constant temperatures (22, 25, and 28°C). When the aquaculture water was heated to the three constant temperature states, it needed to consume 8.56×105, 1.02×106 and 1.22×106 MJ of energy respectively, which were equal to the amount of energy released by the complete combustion of 29.3, 35.1 and 41.8 t standard coal. Moreover, it is concluded that the artificial temperature increase in winter maintains the temperature in the range of 22~25°C to provide the highest heating efficiency. This conclusion can provide theoretical basis and application reference for industrialized aquaculture in winter.

Survey on analytical and numerical methods for lightning-induced voltages calculations

Survey on analytical and numerical methods for lightning-induced voltages calculations

THE RESEARCH OF IMPLEMENTATION OF NUMERICAL RIGOROUS MATHEMATICAL METHODS WITH THE PARAMETER OF THE MEMBERS NUMBER IN THE TAYLOR SERIES

The current level of development of geoinformation technologies makes it possible to determine the cartometric properties of terrain objects with a user-defined accuracy. The author of this paper proposes a mathematical model that allows to implement the function of converting geodetic coordinates into rectangular flat Gauss-Kruger projections in a software environment based on the setting of the parameter of the number of members in the Taylor series, adjusting the accuracy of the coordinate transformation and their dimension. The purpose of this work is to implement a mathematical model of a numerical approximate computer method of converting geodetic coordinates into flat rectangular Gauss-Kruger projections. The results of this study will also be used to create functions for converting coordinates from rectangular flat Gauss-Kruger projections to geodetic coordinates and from one 6-degree zone of the Gauss-Kruger projection to another, taking into account the parameter of the number of members in the Taylor series. The proposed mathematical models are recommended to be implemented in the MATLAB or PhyCharm using the necessary libraries. The following studies will focus on determining the areas and lengths of objects located in two or more 6-degree zones of the Gauss-Kruger projection.

Identification of the effects of pathogenic genetic variations of human CYP2C9 and CYP2D6: an in silico approach

Genetic variations in the human cytochrome P450 family 2 subfamily C member 9 (CYP2C9) and cytochrome P450 family 2 subfamily D member 6 (CYP2D6) genes may affect drug metabolism and lead to alterations in phenotypes. Genetic variations are associated with toxicity, adverse drug reactions, inefficient treatment. Various in silico tools were combined to investigate the deleterious effects of missense non-synonymous single nucleotide polymorphisms (nsSNPs) of the human CYP2C9 and CYP2D6. The structural and functional effects of the high-risk non-synonymous SNPs in the human CYP2C9 and CYP2D6 were predicted by numerous computational mutation analysis methods. Out of 24 pathogenic missense SNPs in the CYP2C9, 22 nsSNPs had a decreasing effect on protein stability and 13 SNPs were showed to be located at conserved positions. Out of 27 high-risk deleterious non-synonymous SNPs in the human CYP2D6, 21 SNPs decreased protein stability and 16 nsSNPs were predicted to be positioned at conserved regions. Our present study suggests that the identified functional SNPs may affect drug metabolism associated with CYP2C9 and CYP2D6 enzymes.

Spatio-temporal characterization of tightly focused femtosecond laser fields formed by paraboloidal mirrors with different F-numbers.

The focusing spatiotemporal property of a femtosecond laser pulse is presented under tight focusing conditions by using the frequency-resolved incident electric field and vector diffraction formulas with the wavefront correction term. In the ideal case, the focused laser intensity reaches its maximum at the F-number of ∼0.35 due to the strong diffraction effect under extremely tight focusing conditions. In spatio-temporal coupling distortion cases, their spatiotemporal Strehl ratios show a trend of improvement as the F-number decreases and this phenomenon is mainly concentrated along the y-direction. Based on the numerical calculation method used in this work, the precise information of tightly focused ultra-intense femtosecond laser fields can be obtained, which is crucial for assessing a focused intensity and describing the motion of charged particles under an extremely strong electric field. Moreover, the evolution law of focal fields with spatiotemporal distortions found in this paper can offer some theoretical guidance for realizing ultrahigh laser intensity in the near future.

Mechanism of Cement Deep Mixing and Design Method Improving Soft Ground in Mekong Delta

Soil improvement technique for embankment fill is often needed to rapidly improve the strength of the soft ground. In recent years, the cement deep mixing (CDM) method has been commonly used as an alternative to improve the soft soil foundation of embankment. This method is a reasonable solution used for several applications as to treat the soft soil behind the bridge abutment, to minimize settlement and enhance the bearing capacity of soil foundation for a storage tank, to support segmental retaining walls, and to prevent differential settlement between a new embankment over soft soil and existing embankment where the settlement has ceased. The stability of cement column stabilized embankments can be analyzed either by a numerical calculation method such as the finite element method (FEM) or by a limit equilibrium method. The numerical calculation methods require reliable material parameters as determined by field and laboratory tests or in-situ on excavated columns and on the unstabilized soil. Another method considering simplified method is limit equilibrium method. In analysis of this method, the stability of cement column is analyzed by assuming that failure of the cement columns and the soil.

Refraction correction for deep-water three-dimensional visual measurement based on multi-objective optimization.

Refraction-induced errors affect the accuracy of three-dimensional visual measurements in deepwater environments. In this study, a binocular camera refractive imaging model was established, and a calibration method for the refraction parameters was proposed for high-accuracy shape and deformation measurements in deep-water environments. First, an initial estimate of the refractive axis was obtained using a three-dimensional calibration target. Then, the errors in the distance between the spatial point pairs and the reprojection errors are taken as the dual optimization objectives, and the Non-dominated Sorting Genetic Algorithm II is applied to optimize the refraction parameters. To efficiently calculate the reprojection error, an improved numerical computation method is proposed to accelerate the calculation of the analytical forward projection. Underwater experiments were conducted to verify the method's effectiveness. The results showed that the average error of the absolute position of the reconstructed points was less than 1.1 mm and the average error of the displacement was less than 0.04 mm. This study provides a sound solution for accurate three-dimensional visual measurement in deep-water environments.

Open-source Python library for modeling coupled thermo-hydro-mechanical (THM) processes

Abstract. The interactions between temperature, fluids, and mechanical properties in a repository system are essentially described scientifically by coupled thermo-hydro-mechanical (THM) processes. THM modeling, i.e., the prediction of the behavior of materials under different conditions, is the fundamental numerical tool here. The confident handling and deep understanding of numerical computation methods is thus the prerequisite for performing and evaluating preliminary safety analyses in the site selection process. At the Federal Office for the Safety of Nuclear Waste Management (BASE), a software library for the simulation of coupled THM processes is currently being developed. The main goal of the in-house development is an open-source toolbox in the scripting language Python and is motivated by several long-term sub-goals: targeted development of expertise within BASE regarding numerical modeling of safety-relevant aspects in the long-term safety analyses; diversification of the testing capabilities regarding the preliminary safety investigations by means of an in-house, independent modeling software; foundation of a library of known benchmarks and evaluation examples for the comparison of different software tools; documentation and processing of basic THM scenarios for internal or, if necessary, public technical training. The focus of this development is on creating a toolbox that is easy to use and at the same time highly flexible. The main methodical aspects are as follows: building a new library based on the pyGIMLi pre- and postprocessing framework (Rücker et al., 2017); creating a finite-element reference implementation in the Python scripting language for maximal transparency; creating an easy-to-use interface to the solution of the weak formulation for the finite-element theory with expressions of a symbolic manner allowing maximal flexibility; defining an interface to allow for the integration of alternative, third-party high-performance libraries; creating a collection of Jupyter notebooks of well-documented test cases and benchmarks. Choosing the open-source approach ensures the best possible transparency and, in the long term, also allows the provision of appropriately quality-assured and documented simulation tools to the public. The presented poster shows the current development status of the software library and the currently implemented quality assurance concepts and gives an outline of the potential applications of the library.

Parameter Calibration and System Design of Material Lifting System for Inclined Shaft Construction

As a key transportation equipment in the construction of long tunnels with large slope, the material hoisting system plays an important role in the transportation of materials in sloping shafts. This paper proposes a parameterized calibration scheme for the hoisting system based on the structure and working principle of the hoisting system, taking the wire rope, hoist, motor and overhead wheel as the research objects, and according to the relevant industry specifications and numerical calculation methods. Based on the structural design and functional analysis of the hoisting system, a reasonable control system, monitoring system and safety protection devices are designed, and the calibration scheme and the designed system are introduced into the Dianzhong water diversion project for verification. The parameters of each component of the hoisting system were calculated as follows: maximum breaking tension value of wire rope 490.29 KN, drum diameter 2000 mm, motor hoisting power 213.7 KW, and the system design was as follows: control system selects frequency conversion electric control method, safety protection device selects ZDC30-2.5 anti-running device. The results show that: the hoisting system components structure parameters meet the specification requirements—safety protection devices can effectively prevent the occurrence of sports car slippage and man-car jumping rail overturning accident—to meet the requirements of the construction period transport capacity and transport safety. The relevant experience can provide the basis for the design of a material hoisting system for a similar inclined shaft construction.

Numerical calculation method for the mean free path of single-mode semiconductor nanosheets with surface roughness

A numerical calculation method is proposed to compute the transport mean free path of single-mode semiconductor nanosheets with surface roughness, where the mean free path is extracted from the statistical average of the logarithm of the dimensionless resistance. The present method requires only a computationally less demanding coherent transmission probability, and is applicable to wider channel length ranges from the quasi-ballistic to the localization regime. The channel thickness, T w, dependence of the mean free path calculated by the proposed method within the effective mass approximation shows the well-known T W 6 dependence for thicker T w, while it becomes weaker for thinner T w.

Improving numerical methods for the steel yield strain calculation in reinforced concrete members with Machine Learning algorithms

Improving numerical methods for the steel yield strain calculation in reinforced concrete members with Machine Learning algorithms

Probability life calculation model of beam element application and study in welded structures reliability analysis

Statistical size and geometrical size are the main factors affecting the service life of mechanical structure calculation. To explore the reliability of the lifespan of beam structures, a probability lifespan numerical calculation method based on Vector Form Intrinsic Finite Element Method (VFIFEM) was proposed, and the method was verified through full lifespan experiments on I-beam welded structures. First, a fatigue fracture model that considers the coupling of residual stress (RS) and cyclic load variations was established. Based on this fatigue fracture model, a probability lifespan calculation model for beam elements was defined by proposing a cross-sectional shape correction coefficient and a position correction coefficient. The proposed probability lifespan model for beam elements was used to calculate the I-beam welded structure, and the calculated results were compared with the full lifespan experiment results, which were close in statistical results, with all experimental results falling within the [10%, 90%] interval except for one experiment. This method effectively couples the influence of statistical size and geometric size on probability lifespan, providing a new approach for the structure probability lifespan calculation in the future.

A Review of Numerical Simulation and Analytical Calculation Methods for the Study of Flow over a Wedge

Abstract: The study of flow over a wedge holds immense significance in diverse domains, encompassing aerodynamics and heat transfer applications. This research paper presents a comprehensive investigation of essential flow parameters, including pressure, temperature, velocity, and shock wave characteristics. Moreover, it offers a comparative analysis between analytical and numerical approaches for studying flow over a wedge. Theoretical analyses involve calculating vital parameters like pressure ratio and temperature ratio using 1-D inviscid compressible flow equations coupled with conservation laws for energy, mass, and momentum. On the other hand, the numerical investigation employs Computational Fluid Dynamics (CFD) techniques, specifically the ANSYS Fluent CFD Code, to calculate a wide range of parameters and visualise the flow characteristics for the wedge geometry. In contrast, the ANSYS Fluent simulation employs 2-D inviscid compressible equations to conduct a detailed study of flow behaviour past the wedge geometry. Throughout the paper, the key flow parameters are meticulously analysed, taking into account both analytical and numerical results.

Phylogenetic inference of the emergence of sequence modules and protein-protein interactions in the ADAMTS-TSL family.

Numerous computational methods based on sequences or structures have been developed for the characterization of protein function, but they are still unsatisfactory to deal with the multiple functions of multi-domain protein families. Here we propose an original approach based on 1) the detection of conserved sequence modules using partial local multiple alignment, 2) the phylogenetic inference of species/genes/modules/functions evolutionary histories, and 3) the identification of co-appearances of modules and functions. Applying our framework to the multidomain ADAMTS-TSL family including ADAMTS (A Disintegrin-like and Metalloproteinase with ThromboSpondin motif) and ADAMTS-like proteins over nine species including human, we identify 45 sequence module signatures that are associated with the occurrence of 278 Protein-Protein Interactions in ancestral genes. Some of these signatures are supported by published experimental data and the others provide new insights (e.g. ADAMTS-5). The module signatures of ADAMTS ancestors notably highlight the dual variability of the propeptide and ancillary regions suggesting the importance of these two regions in the specialization of ADAMTS during evolution. Our analyses further indicate convergent interactions of ADAMTS with COMP and CCN2 proteins. Overall, our study provides 186 sequence module signatures that discriminate distinct subgroups of ADAMTS and ADAMTSL and that may result from selective pressures on novel functions and phenotypes.

Solving the RNA inverse folding problem through target structure decomposition and Multiobjective Evolutionary Computation

The RNA inverse folding problem involves discovering a nucleotide sequence that folds into a desired target structure. Although numerous computational methods have been proposed over the years to tackle the problem, none have successfully solved the complete Eterna100 set. The Eterna100 set is widely recognized as a benchmark in this field. Therefore, there is still ample room for improvement in this area. This paper aims to address this challenge by introducing eM2dRNAs, an enhanced version of our previous approach called m2dRNAs, which is a multiobjective metaheuristic to design RNA sequences. By introducing eM2dRNAs, we aim to make significant advancements in RNA inverse folding. Our approach starts with the recursive decomposition of the target structure, simplifying the problem to be solved. We conducted a comparative study of our method against several published methods using the Eterna100 benchmark. The results showed that our proposal performs significantly better than the other methods across almost all metrics and categories considered, thus achieving our objective of improving the ability to solve the RNA inverse folding problem.

Development and Validation of a Novel In Vitro Joint Testing System for Reproduction of In Vivo Dynamic Muscle Force.

In vitro biomechanical experiments utilizing cadaveric specimens are one of the most effective methods for rehearsing surgical procedures, testing implants, and guiding postoperative rehabilitation. Applying dynamic physiological muscle force to the specimens is a challenge to reconstructing the environment of bionic mechanics in vivo, which is often ignored in the in vitro experiment. The current work aims to establish a hardware platform and numerical computation methods to reproduce dynamic muscle forces that can be applied to mechanical testing on in vitro specimens. Dynamic muscle loading is simulated through numerical computation, and the inputs of the platform will be derived. Then, the accuracy and robustness of the platform will be evaluated through actual muscle loading tests in vitro. The tests were run on three muscles (gastrocnemius lateralis, the rectus femoris, and the semitendinosus) around the knee joint and the results showed that the platform can accurately reproduce the magnitude of muscle strength (errors range from -6.2% to 1.81%) and changing pattern (goodness-of-fit range coefficient ranges from 0.00 to 0.06) of target muscle forces. The robustness of the platform is mainly manifested in that the platform can still accurately reproduce muscle force after changing the hardware combination. Additionally, the standard deviation of repeated test results is very small (standard ranges of hardware combination 1: 0.34 N~2.79 N vs. hardware combination 2: 0.68 N~2.93 N). Thus, the platform can stably and accurately reproduce muscle forces in vitro, and it has great potential to be applied in the future musculoskeletal loading system.

Investigation on the Aerodynamic Parameters of the Triangle Shape of Tall Buildings by Using of CFD Method

Wind loading in large buildings has always been a major challenge for civilian engineers. For this purpose, presenting the optimum exterior forms of a building exposed to the wind flow and analyzing aerodynamic forces, including resistance force, bending, and twisting moments, are challenging issues for designers. Nowadays, by combining various numerical calculation methods, like neural networks, genetic algorithms, and other methods, by changing some parameters, they optimize the external form of the building based on aerodynamic parameters. In this research, three optimized triangular models will be investigated using the computational fluid dynamics method. For wind flow, a velocity profile is used in the three simulations, and Reynolds’ Navier–Stokes average equations are used to solve momentum relationships. Additionally, the κ-ε method was used to calculate Reynolds stresses. The results show that the optimized N3 model is in the most optimal condition possible in terms of aerodynamic parameters such as drag, torsion moment, and vortices behind the building. Nowadays, the neural network algorithm is one of the most famous numerical methods for optimizing hull shapes. However, this approach cannot improve aerodynamic parameters either. Hence, computational fluid dynamics is used to deeply analyze. This research is one step forward to assess the optimized hull shapes of tall buildings. All tests are conducted using STAR CCM+.

A hybrid model based on LSTM neural networks with attention mechanism for short-term wind power forecasting

Wind power plants have gained prominence in recent decades owing to their positive environmental and economic impact. However, the unpredictability of wind resources poses significant challenges to the secure and stable operation of the power grid. To address this challenge, numerous computational and statistical methods have been proposed in the literature to forecast short-term wind power generation. However, the demand for more accurate and reliable methodologies to tackle this problem remains. In this context, this paper proposes a new hybrid framework that combines a statistical pre-processing stage with an attention-based deep learning approach to overcome the shortcomings of existing forecasting strategies in accurately predicting multi-seasonal wind power time series. The proposed ensemble model involves a data transformation stage that normalizes the data distribution, along with modeling and removing multiple seasonal patterns from the historical time-series. Considering these results, the proposed model further incorporates an LSTM Recurrent Neural Network (RNN) model with an attention mechanism, for each month of the year, to better capture the relevant temporal dependencies in the input residuals sequence. The model was trained and evaluated on hourly wind power data obtained from the Spanish electricity market, spanning the period from 2008 to 2019. Experimental results show that the proposed model outperforms well-established DL-based models, achieving lower error metrics. These findings have potential applications in energy trading, grid planning, and renewable energy management.

Structural Stability Analysis of Multistory Building Structure under Wind Load Conditions

In the current research the effect of wind load on structural stability of building structure is evaluate using techniques of Computational Fluid Dynamics. The CFD analysis on building is conducted using ANSYS simulation package. The FSI simulations considered the complex interactions between the structural components and the surrounding fluid flow, providing valuable insights into the structural response and its vulnerability to external loading conditions. Through a combination of computational tools and numerical methods, the study was able to accurately predict the structural response, including deformations, stresses, and critical failure points.