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A Neural Network Constitutive Model and Automatic Stiffness Evaluation for Multiscale Finite Elements

APPLIED SCIENCES-BASEL 2025年第7期15卷 3697-3697页

作者： Mouratidou, Aliki D. Stavroulakis, Georgios E. Tech Univ Crete Inst Computat Mech & Optimizat Sch Prod Engn & Management Khania 73100 Greece

A neural network model for a constitutive law in nonlinear structures is proposed in this paper. The artificial neural network (ANN) model is constructed based on a data set of responses from representative volume elements, which was calculated by finite elements and using an open scientific software machine learning platform. The tangential stiffness matrix, which can be used within a multiscale finite element analysis, is calculated via the method of automatic differentiation. Two types of constitutive neural networks are proposed. The first approach involves training a residual model with three respective surrogate models for the stress components, ensuring less computing cost. The second approach considers a separate ANN for each stress component, ensuring a high rate of convergence. The numerical results are compared with the given data set as well as with the results obtained after applying a polynomial regression. The loss function, without and including the Sobolev metrics, is considered. In addition, a physics-informed constitutive neural model, which enforces hyperelasticity principles, is also analyzed. The choice of the hyperparameters is discussed.

关键词： neural network constitutive law composite structure representative volume element computational procedure material consistency-informed constitutive neural network

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Nanoparticles Shape-Dependent Thermal Analysis of Non-Newtonian Hybrid Nanofluid over a Radiated Stretching Sheet

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BIONANOSCIENCE 2025年第2期15卷 1-20页

作者： AL Garalleh, Hakim Univ Business & Technol Coll Engn Dept Math Sci Jeddah 21361 Saudi Arabia

Chemical activated and magnetized nanomaterials have gained significant attention in several medical applications due to their exceptional thermal and physical attributes. Particularly gold and silver nanoparticles with pure blood, making it suitable for many medical interventions. By taking the full benefits of their advanced and tailored thermophysical attributes, the study's primary aim is to investigate shape-dependent thermal transport dynamics in hybrid bio-nanofluid by employing a computational-based theoretical model. The physical model incorporates the Cross-viscosity model with the aid diverse factors such as heat source, thermal radiation, Brownian motion, and magnetohydrodynamics (MHD) consequences. The system of governing partial differential equations (PDEs) is shifted into a coupled system of ordinary differential equations (ODEs) by introducing similarity variables. Numerical treatment of resulting system is made through a well-known and robust bvp4c computational procedure. The effectiveness of the influential parameters on velocity, temperature, and concentration profile is examined comprehensively. It is noted that, postive variation in the numeric values of heat source and radiation parameters enhanced the heat transfer process. Furthermore, cylindrical-shaped nanoparticles enhance thermal transport in hybrid blood nanofluids because of reduced agglomeration and superior thermal conductivity compared to spherical nanoparticles. Cylindrical shape influences the temperature distribution rapidly with variant concentration of nanoparticles due to more conductive routes, and improved thermal conductivity facilitates effective heat dissemination within the hybrid blood nanofluids. The elongated shape promotes better thermal mixing and directional heat transfer, making them more effective for optimizing heat dissipation. Moreover, velocity and temperature distribution are sensitive to thermal slip consequences. The proposed results could be useful in se

关键词： Hemodynamics computational procedure Thermal transport mechanism Shapes dynamics MHD Hybrid nanofluids

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Chemisorption of NO2 on V-Based SCR Catalysts: A Fundamental Study toward the Mechanism of "Fast SCR" Reaction

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JOURNAL OF PHYSICAL CHEMISTRY C 2019年第33期123卷 20451-20458页

作者： Wang, Xiangmin Du, Xuesen Yang, Guangpeng Xue, Jingyu Chen, Yanrong Zhang, Li Chongqing Univ Key Lab Low Grade Energy Utilizat Technol & Syst Minist Educ PRC Chongqing 400044 Peoples R China Chongqing Univ Sch Energy & Power Engn Chongqing 400044 Peoples R China Georgia Inst Technol Brook Byers Inst Sustainable Syst Sch Civil & Environm Engn Atlanta GA 30332 USA

The "fast selective catalytic reduction (SCR)" process, with its superior efficiency, is promising for removing NOx from flue gas with low temperature and high gas velocity. Chemisorption of NO2 is a crucial step in this heterogeneous catalysis process. In this study, density functional theory calculations and experimental methods were implemented to study the chemisorption behaviors of NO2 on the industrial V-based SCR catalyst. Both the (001) and (101) surfaces of the TiO2 support were applied in the modeling and calculation process. Theoretical results show varied profiles of NO2 adsorption on the fresh and reduced V2O5/TiO2 catalysts. For the fresh catalyst, NO2 tends to adsorb on the TiO2 support rather than on the vanadium oxide. On the contrary, NO2 exhibits a strong interaction with the -OH site of the reduced vanadium oxide. NO2 temperature-programmed desorption, X-ray photoelectron spectroscopy, and a designed redox experiment were implemented to verify the calculation results. On the basis of the NO2 adsorption behaviors, we concluded two different reaction mechanisms of the "fast SCR" reaction. One is that NO2 significantly accelerates the reoxidation process of the reduced vanadia sites and the other is that the adsorbed NO2 on TiO2 reacts with NH3 and NO in the path of the "Nitrate route" with the assistance of an adjacent vanadia site.

关键词： Chemisorption Nitrogen Dioxide computational procedure Catalysts

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Plausible Petri nets as self-adaptive expert systems: A tool for infrastructure asset monitoring

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COMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING 2019年第4期34卷 281-298页

作者： Chiachio, Manuel Chiachio, Juan Prescott, Darren Andrews, John Univ Nottingham Fac Engn Resilience Engn Res Grp Nottingham NG7 2RD England Univ Granada Dept Struct Mech & Hydraul Engn Granada Spain

This article provides a computational framework to model self-adaptive expert systems using the Petri net (PN) formalism. Self-adaptive expert systems are understood here as expert systems with the ability to autonomously learn from external inputs, like monitoring data. To this end, the Bayesian learning principles are investigated and also combined with the Plausible PNs (PPNs) methodology. PPNs are a variant within the PN paradigm, which are efficient to jointly consider the dynamics of discrete events, like maintenance actions, together with multiple sources of uncertain information about a state variable. The manuscript shows the mathematical conditions and computational procedure where the Bayesian updating becomes a particular case of a more general basic operation within the PPN execution semantics, which enables the uncertain knowledge being updated from monitoring data. The approach is general, but here it is demonstrated in a novel computational model acting as expert system for railway track inspection management taken as a case study using published data from a laboratory simulation of train loading on ballast. The results reveal self-adaptability and uncertainty management as key enabling aspects to optimize inspection actions in railway track, only being adaptively and autonomously triggered based on the actual learnt state of track and other contextual issues, like resource availability, as opposed to scheduled periodic maintenance activities.

关键词： Imprecise knowledge train load monitoring data computational procedure Railway track Expert System self-adaptive State variable maintenance activities external input Petri nets computational modeling

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An Endoscopic Optical Coherence Tomography System with Improved Precision of Probe Positioning

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BIOMEDICAL ENGINEERING-MEDITSINSKAYA TEKNIKA 2019年第1期53卷 6-10页

作者： Frolov, S., V Potlov, A. Yu Tambov State Tech Univ Tambov Russia

An improved optical coherence tomography system equipped with an endoscopic probe is presented. A key feature of the described device is the possibility of high-precision positioning of the endoscopic probe. This effect is achieved by the use of microelectromechanical systems for assessing the angular velocity and acceleration. The scanning process is optically synchronized with the process of calculation of the spatial coordinates of the endoscopic probe. The expediency of using the developed system for real-time evaluation of the biomechanical properties of blood vessel walls or their phantoms is discussed.

关键词： Real time Microelectromechanical systems computational procedure blood vessel wall Precision precise registration spatial coordinates tomography system optical coherence tomography

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Method for Realizing on Line Condition Monitoring of Protective Device Based on Data of Information Processing System

Method for Realizing on Line Condition Monitoring of Protect...

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International Conference on Electronics Technology (ICET)

作者： Luo Kun Shi Yongxiao Liu Li Li Zhengxin Zhou Kun Hao Dongfang Bijie Power Supply Bureau BiJie China

ISBN: (数字)9781728162836

ISBN: (纸本)9781728162843

Aiming at the problems existing in the traditional fault mode and impact analysis (FMEA) method in the risk assessment of relay protection devices, a fuzzy TOPSIS-FMEA method combining fuzzy evidence reasoning and TOPSIS is introduced to calculate the risk assessment of relay protection devices. . The method uses the fuzzy confidence structure to carry out the fuzzy processing of O (Occurrence), S (Severity) and D (Detection) of the three fault factors of FMEA, and reduces the subjective error of the maintenance personnel's rating in principle. Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) is introduced as a multi-index comprehensive evaluation sorting method to solve the problem that the traditional FMEA cannot distinguish two fault modes due to the same RPN value in the calculation process. Finally, the effectiveness of the method is proved by an example.

关键词： fuzzy reasoning technique for order preference by similarity to ideal solution failure mode and influence degree relay protection risk assessment Relay protection Risk Assessment Risk Management fuzzy reasoning FAILURE MODES Failure Mode and Effect Analysis safety devices computational procedure Fuzzy

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Low-Dimension Robust computational Algorithm for a Linear Distributed Parameter Water Hammer Model 23

Low-Dimension Robust Computational Algorithm for a Linear Di...

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23rd International Conference on System Theory, Control and Computing (ICSTCC)

作者： Danciu, Daniela Stinga, Florin Univ Craiova Dept Automat Control & Elect Craiova Romania

ISBN: (纸本)9781728106991

Water hammer is a hydraulic phenomenon occurring in cases of sudden load drop e.g. hydraulic turbine shutdown. These undesirable events lead to fast transients processes which require taking into account the distributed parameters. As a system with distributed parameters, the most realistic mathematical model of the water hammer phenomenon is that described by hyperbolic Partial Differential Equations. The qualitative evaluation of this phenomenon is performed by means of its computational model obtained by using a loworder robust computational algorithm previously introduced. Simulated experiments are discussed from the points of view of the engineering problem as well as of the numerical approach.

关键词： Distributed Parameter Systems Hyperbolic Partial Differential Equations Water hammer computational procedure

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Implementation of an Airfoil Information Database for Usage in Conceptual Aircraft Wing Design Process

Implementation of an Airfoil Information Database for Usage ...

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AIAA Science and Technology (SciTech) Forum and Exposition

作者： Schueltke, F. Stumpf, E. Rhein Westfal TH Aachen Inst Aerosp Syst ILR Wuellnerstr 7 D-52062 Aachen Germany

ISBN: (数字)9781624105784

ISBN: (纸本)9781624105784

This paper presents an airfoil information database which is intended to be used during the wing sizing and analysis process within the conceptual aircraft design phase. The focus of this paper in general lies in the setup, creation and handling of such a database. The database itself consists of five tables including an overview of all airfoils stored in the database, the belonging airfoil coordinates, a set of aerodynamic input data in terms of free stream conditions, and two tables for the information of the flow solution of the corresponding free stream condition. For the flow solution, the 2D flow solver MSES is used to calculate these data and the SQL database format is utilized to store them. This process of calculation and storage can be executed fully automatized and in parallel via a Python script for a large input matrix of free stream conditions. Within this paper, a first version of the database is built including three airfoils. This version is available at CeRAS for public use. The results of the flow solution stored in the database are compared to commonly used handbook methods. It is found that these handbook methods are not accurate enough to estimate important parameters that are needed for the wing design process or the methods even depend on airfoil information. This underlines the need for an airfoil information database to close the gap between the requirements arising from the top-level aircraft requirements and the wing sizing process.

关键词： Database Wings Airfoils computational procedure design process incoming data information Aircraft conceptual

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Interpolation method for 2S-DIRK-based EMT simulations

Interpolation method for 2S-DIRK-based EMT simulations

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2020 Tsinghua - HUST-IET Electrical Engineering Academic Forum

作者： Xiaohui Ye Yong Tang Yiming Lu Guangxian Lyu Yantao Zhang Xinli Song China Electrical Power Research Institute Haidian District Beijing 100192 China

ISBN: (纸本)9781839533914

Interpolation algorithm plays an important role in the fixed step integration method, it can accurately get the action time of the switch. 2S-DIRK method has L-stability and 2-order accuracy, but the linear interpolation method based on 2S-DIRK will reduce the calculation accuracy to 1-order, which cannot be used in large power grid simulation. In this paper, based on Runge Kutta formula, a special 2-order interpolation algorithm was proposed. This algorithm does not satisfy the value of the middle point but can ensure that the accuracy of the interpolation process is not less than 2-order. The L-stability and the 2 order of accuracy in 2S-DRIK method are guaranteed. Finally, a combined example of LCC-HVDC system and IEEE9 system is used to verify that the proposed method can maintain the 2-order of accuracy in the whole calculation process.

关键词： Linear interpolation 2S-DIRK butcher tableau EMTP accuracy linearly independant Electromagnetic Transients Program Interpolation Arithmetic computation accuracy computational procedure Interpolation Emergency Medical Technicians SLC22A3 gene ITK gene

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Multi-layer Modeling for Capability Generation of UAV Swarm System

Multi-layer Modeling for Capability Generation of UAV Swarm ...

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IEEE International Conference on System of Systems Engineering (SoSE)

作者： Jun Shao Minghao Li Kewei Yang College of Systems Engineering National University of Defense Technology Changsha China

ISBN: (数字)9781728180502

ISBN: (纸本)9781728180519

Unmanned aerial vehicle (UAV) swarm, as a large-scale integrated system, has been widely used in civil and military fields. Building a model of a drone swarm and assessing the system capabilities is a challenging task. In this paper, a multi-layer network modeling method, considering the indicator, logic and collaboration of the constituent systems (CSs), is proposed to build the architecture of the UAV swarm system. On this basis, the generation processes of system-level capabilities in multi-layer networks are studied. Finally, we take the UAV swarm system as a case to illustrate the calculation process and results of the proposed model. It shows that the multi-layer network model can effectively assist the system-level capability generation of the UAV swarm, and the network structure can have both positive and negative effects on the system.

关键词： capability generation UAV swarm system system architecture multi-layer modeling system integration Systems Integration drone honey bees Unmanned Aerial Vehicle multilayer network dike swarms computational procedure Building systems hierarchical network NETWORK STRUCTURE Civil

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