A physics-informed neural network for simulation of finite deformation in hyperelastic-magnetic coupling problems

Recently,numerous studies have demonstrated that the physics-informed neural network(PINN)can effectively and accurately resolve hyperelastic finite deformation problems.In this paper,a PINN framework for tackling hyperelastic-magnetic coupling problems is proposed.Since the solution space consists of two-phase domains,two separate networks are constructed to independently predict the solution for each phase region.In addition,a conscious point allocation strategy is incorporated to enhance the prediction precision of the PINN in regions characterized by sharp gradients.With the developed framework,the magnetic fields and deformation fields of magnetorheological elastomers(MREs)are solved under the control of hyperelastic-magnetic coupling equations.Illustrative examples are provided and contrasted with the reference results to validate the predictive accuracy of the proposed framework.Moreover,the advantages of the proposed framework in solving hyperelastic-magnetic coupling problems are validated,particularly in handling small data sets,as well as its ability in swiftly and precisely forecasting magnetostrictive motion.

Virtually coupled train set control subject to space-time separation:A distributed economic MPC approach with emergency braking configuration

The emerging virtual coupling technology aims to operate multiple train units in a Virtually Coupled Train Set(VCTS)at a minimal but safe distance.To guarantee collision avoidance,the safety distance should be calculated using the state-of-the-art space-time separation principle that separates the Emergency Braking(EB)trajectories of two successive units during the whole EB process.In this case,the minimal safety distance is usually numerically calculated without an analytic formulation.Thus,the constrained VCTS control problem is hard to address with space-time separation,which is still a gap in the existing literature.To solve this problem,we propose a Distributed Economic Model Predictive Control(DEMPC)approach with computation efficiency and theoretical guarantee.Specifically,to alleviate the computation burden,we transform implicit safety constraints into explicitly linear ones,such that the optimal control problem in DEMPC is a quadratic programming problem that can be solved efficiently.For theoretical analysis,sufficient conditions are derived to guarantee the recursive feasibility and stability of DEMPC,employing compatibility constraints,tube techniques and terminal ingredient tuning.Moreover,we extend our approach with globally optimal and distributed online EB configuration methods to shorten the minimal distance among VCTS.Finally,experimental results demonstrate the performance and advantages of the proposed approaches.

Application of General Fractal Dimension to Coupling Fault Diagnosis

This paper presents the coucept of general and sensitive dimension, and also proposes the calculation formula of the general dimension least squares method. By calculating and analyzing the power spectrum and general dimension from the fault sample, the relationship is achieved between sample status and the general dimension from vibration signals of the equipment so as to provide reference to fault diagnosis. Furthermore, a correlation function of general dimension is proposed, and calculations are carried out for a monitor signal and samples signal. The diagnosis method based on fractal theory is effective through the concrete examples of the steam electric generating set fault diagnosis, and the correlation coefficient of general dimension between a monitor signal and samples signal can improve the accuracy for fault diagnosis.

Blow-up Sets to a Coupled Heat System

This paper deals with a heat system coupled via local and localized sources subject to null Dirichlet boundary conditions. In a previous paper of the authors, a complete result on the multiple blow-up rates was obtained. In the present paper, we continue to consider the blow-up sets to the system via a complete classification for the nonlinear parameters. That is the discussion on single point versus total blow-up of the solutions. It is mentioned that due to the influence of the localized sources, there is some substantial difficulty to be overcomed there to deal with the single point blow-up of the solutions.

文化和旅游融合发展的多重驱动路径研究——基于“需求—供给—支持”框架的组态分析

文旅融合是实现我国旅游业高质量发展的必然要求,也是补齐旅游业发展短板、推进转型升级的内在需要。本文利用耦合协调模型对我国2010—2019年30个省区市的文旅融合发展水平展开评估,随后引入模糊集定性比较分析方法,基于需求、供给和支持3个方面的驱动条件探究我国文旅融合发展路径。研究发现:(1)研究期内我国文旅产业整体发展水平有所提高,但不同地区存在较大的区域异质性。(2)从我国整体文旅融合发展路径来看,需求与支持条件起重要作用,居民消费能力与区位交通条件的作用尤其突出。(3)东、中、西部地区发展路径存在明显差异,东部地区主要为需求—支持条件叠加型发展路径,中部则呈现出支持条件驱动型与需求条件驱动型两种发展路径,西部存在需求条件驱动型与需求—支持条件叠加型两种路径。因此,地方政府应重视供给、需求、支持多重条件的协同匹配,根据地方发展条件切实调整文旅开发策略,有针对性地提升核心驱动能力以突破发展瓶颈。

湖南省高职院校专业设置与产业结构耦合性研究——以航空产业为例

航空产业是我国战略性新兴产业,更是先进制造业的重要组成部分,湖南省航空产业拥有较好的经济总量支撑、雄厚的产业基础和一批竞争力强的市场主体,但也面临着来自周边省份的挑战和通航产业基础较为薄弱的弊端。职业教育与产业发展紧密联系,职业教育为产业发展提供技术与人才支撑。通过分析湖南省高职院校航空类专业设置与航空产业的耦合性,发现存在专业布局与产业布局耦合度、专业规模与产业规模耦合度、技能人才培养规模与产业人才需求耦合度有待提高的问题,以期通过加强顶层设计,对接产业设置专业;发挥聚集效应,构建专业集群;校企深度合作,提升人才适配性进行改善。

粤港澳大湾区高职院校专业设置适应性研究

粤港澳大湾区发展驱动产业结构转型升级,势必会对湾区高职院校的人才培养质量提出更高的要求。通过调查研究发现,湾区高职院校的专业设置与产业结构存在一定的偏离,办学规模滞后产业集群发展、专业设置与市场需求匹配度不高、实践能力培养体系构建不完整、职业教育学生发展不均衡问题凸显。据于此,粤港澳大湾区高职院校应面向产业,构建校企优势互补的发展格局;面向市场,专业设置与市场需要相对接;面向实践,深化职业教育三教改革;面对学生,构建适应生源特点的人才培养模式,完善专业结构,促进学生健康自由全面发展。

基于Level-set法的液体晃荡与弹性液舱耦合作用研究

对基于Level-set法模拟液舱液体晃荡的数值模型进行了改进,实现了对大幅晃荡引起的抨击载荷的模拟.运用水弹性力学理论论述了液体晃荡与弹性液舱耦合作用的分析方法,建立了相应的水弹性力学方程.数值算例与实验结果的比较验证了对抨击载荷模拟的正确性;通过对晃荡载荷引起的结构响应的计算分析,得出一些关于结构响应特性的重要结论.

高职院校专业设置的实践困境、逻辑遵循与路径选择

随着生产技术的迭代更新,作为以技术学习为特征的高等职业教育也受到影响。在此背景下,加强高职院校的专业设置,对提升高素质技术技能人才培养质量具有积极作用。目前高职院校在专业设置上仍然面临内外部产业链对接不强、专业设置趋同、学生素养体现不足等实践困境。为破解僵局,从高职院校专业设置的内部机制切入,提出外部产业链、内部教育端、学生主体三者皆为专业设置的逻辑起点,且它们彼此之间存在内部互动联系。立足于新发展格局,高职院校专业设置应充分考虑外部产业链发展要求、内部教育端需求以及学生主体发展诉求,通过形成三者的耦合机制,为高职院校专业设置走向科学化进程探寻新路径,以切实提高技术技能人才培养质量。

浮式风机一体化模拟的计算参数设置影响研究

随着海上浮式风机的大型化发展,针对漂浮式风机的一体化耦合分析越来越重要。本文利用Simo-Riflex-Aerodyn仿真工具建立OC4-Deepcwind漂浮式风机一体化耦合模型,分析计算时间步长、初始截断时间、弹性结构单元离散数等计算参数对模拟结果的影响,包括浮式基础运动、系缆张力、叶片受力等。结果表明:当计算时间步长为0.005 s、0.01 s、0.02 s时,浮式风机的响应结果差别较小,而计算消耗时间相差较大,0.01 s、0.02 s的计算时间分别是0.005 s的70%、37%。相同工况下,不同参量响应达到稳定所需时间不同,纵荡需要的时间较长,最长达200 s;不同工况下,同一参量达到稳定所需时间也不相同,切出工况需要的时间最短,较额定工况快约60 s。结构单元离散数对塔柱受力影响较小,对叶片变形影响相对明显,当叶片离散数目减小时,响应值增大12%。实际中应根据具体工况选择合理的计算时间步长、初始截断时间和弹性结构单元离散数量。

页岩气水平井暂堵坐封机制与可控暂堵压裂工艺

水平井暂堵转向压裂技术是页岩气增产的关键技术之一。文中采用流体动力学软件FLUENT与离散元方法(DEM)相结合的数值建模方法,研究了水平井暂堵转向压裂技术中暂堵球在井筒中的运移规律以及颗粒间的相互作用。通过建立DEM-DDPM耦合模型发现,施工排量、暂堵球密度、暂堵球直径和压裂液黏度是影响暂堵球坐封效果的主要因素。模拟结果表明:当施工排量在4~6 m^(3)/min时,暂堵球的密度小于或等于流体密度;射孔炮眼磨蚀率在6.15%以内可以有效提高封堵效率;同时,随着压裂液黏度的增加,封堵效率先升后降。该研究结果对于优化水平井压裂暂堵球用量以及施工工艺具有重要的理论意义和指导价值。

基于level set的Eulerian-Lagrangian耦合方法及其应用

提出了一种基于水平集的Eulerian-Lagrangian耦合方法,其中Lagrangian方法采用相容显式有限元拉氏方法,Eulerian方法采用基于近似Riemann解的有限体积Eulerian方法,多介质界面处理采用新的水平集和Ghost方法计算.给出了若干数值算例,包括激波管问题以及金属和气体的运动界面及其大变形问题,并分别与精确解和相容显式有限元拉氏方法的计算结果进行了对比.数值结果表明,该方法计算结果正确,精度较高,能够准确捕捉物质界面,适用于处理大变形问题.

The Quantum Microverse: A Prime Number Framework for Understanding the Universe

This study aims to demonstrate a proof of concept for a novel theory of the universe based on the Fine Structure Constant (α), derived from n-dimensional prime number property sets, specifically α = 137 and α = 139. The FSC Model introduces a new perspective on the fundamental nature of our universe, showing that α = 137.036 can be calculated from these prime property sets. The Fine Structure Constant, a cornerstone in Quantum Electrodynamics (QED) and Quantum Chromodynamics (QCD), implies an underlying structure. This study identifies this mathematical framework and demonstrates how the FSC model theory aligns with our current understanding of physics and cosmology. The results unveil a hierarchy of α values for twin prime pairs U{3/2} through U{199/197}. These values, represented by their fraction parts α♊ (e.g., 0.036), define the relative electromagnetic forces driving quantum energy systems. The lower twin prime pairs, such as U{3/2}, exhibit higher EM forces that decrease as the twin pairs increase, turning dark when they drop below the α♊ for light. The results provide classical definitions for Baryonic Matter/Energy, Dark Matter, Dark Energy, and Antimatter but mostly illustrate how the combined α♊ values for three adjacent twin primes, U{7/5/3/2} mirrors the strong nuclear force of gluons holding quarks together.

基于加权潮流熵和耦合支路介数的大停电故障集构建方法研究

随着电网互联程度的加深,电网因连锁故障引发大停电的概率增大,构建连锁故障集是预防大停电的有效措施之一。首先,研究对电网稳定运行影响巨大的故障支路集,定量评估电网运行状态的加权潮流熵计算方法。然后,结合全过程动态仿真软件,提出基于加权潮流熵和耦合支路介数的大停电故障集构建方法。最后,以某地区电网为例验证所提方法的正确性和有效性。该方法既考虑电网结构变化又考虑电网状态变化,能够准确反映电网故障动态过程。

喷印金属双液滴撞击固体形成气泡的模拟研究

喷墨打印镓金属液滴撞击固体表面时会产生空气夹带,造成气泡沉积出现喷墨打印导线不互联现象,深入理解气泡形成的影响因素是解决此问题的关键。为消除气泡,提高打印导线互联性,本研究使用Ansys Fluent软件,采用VOF耦合水平集方法,建立了二维镓金属双液滴撞击固体铜基板过程的仿真模型,研究了水平壁面温度、双液滴间距、倾斜壁面角度、倾斜壁面温度等参数对金属双液滴撞击固体壁面形成气泡过程的影响规律。研究结果表明,对于水平基板,在不同基板温度下气泡的大小呈现双向变化,金属双液滴间距的增加更有利于液滴铺展。当金属双液滴间距S=D_(0)-2.38D_(0)时,有气泡形成;当S=2.38D_(0)-2.5 D_(0)时,液滴铺展出现断裂,且气泡随温度的增加没有明显变化;当金属双液滴间距S=2.6 D_(0)时,随着温度的增加不再产生气泡,此时喷墨打印液滴表现出最佳精度,提高了打印导线的互联性。对于倾斜基板,使用参数韦伯数(We⊥)和参数(K⊥)表征金属双液滴形成的气泡,当撞击倾斜壁面韦伯数We⊥>15、K⊥>0.035时,液滴会在固体表面上形成气泡;当We⊥>16、K⊥>0.04时,形成的气泡直径随壁面温度的增加而减小;当15<We⊥<16、0.035<K⊥<0.04时,液滴出现铺展断裂,并且气泡直径随着壁面温度的增加而减小;当5<We⊥<15、0.015<K⊥<0.035时,液滴铺展断裂且气泡直径变大;当We⊥<5、K⊥<0.01时,液滴在基板形成的气泡消失,此时为喷墨打印液滴的最佳精度,可提高打印导线的互联性。该研究为优化喷墨打印金属液滴的工艺提供了重要理论依据,有望在实际应用中消除气泡,进一步提高喷墨打印导线的互联性。

路内停车与动态交通的耦合关系建模研究

为了研究路内停车与动态交通之间的相互关系,采用层次分析法对路内停车与动态交通之间的影响因素进行定量分析。利用MATLAB计算出各耦合指标的合成权重,依据合成权重选择停车频数、停车平均耗时和道路交通量作为研究的耦合指标。构建路内停车与动态交通的耦合关系模型,并提出相应的停车泊位设置方案。通过对子实路路内停车和动态交通流的分析对其耦合关系进行实例验证。研究结果表明:实施停车泊位设置方案,使动态交通流的行驶速度平均增加11.1%,有效地降低了路内停车对动态交通流的负面影响,并提高了道路的运行效率。

大型混流式机组水发联轴螺栓拆卸研究

大型混流式水轮发电机大修主要任务完成水轮机和发电机拆卸检查回装,而其中各联轴螺栓和过盈配合部位的拆卸过程尤为重要,一旦发生螺栓卡死的情况将大大影响检修工期。从某电站大型混流式机组检修时大轴螺栓卡死原因上深入分析,提出了多条改善措施,经过实施后大大降低了螺栓卡死发生的概率。

界面捕捉中耦合Level-set与VOF算法

针对传统的level-set方法在处理界面问题时守恒性差的缺点,提出了一种耦合level-set方法和VOF方法的算法(CLSVOF)。不仅保持了level-set界面光滑性好的特点,还结合了VOF高守恒性的优点。Level-set方程的求解采用五阶WENO格式,而VOF的体积分数输运方程采用Gueyffier的界面重构方法求解。三维数值计算结果表明这种耦合算法对level-set的守恒性有明显的改善。

Nonlinear Dynamic Characteristic Analysis of the Shaft System in Water Turbine Generator Set

A 3D finite element vibration model of water turbine generator set is constructed considering the coupling with hydropower house foundation. The method of determining guide bearing dynamic characteristic coefficients according to the swing of the shaft is proposed, which can be used for studying the self-vibration characteristic and stability of the water turbine generator set. The method fully considers the complex supporting boundary and loading conditions; especially the nonlinear variation of guide bearing dynamic characteristic coefficients and the coupling effect of the whole power-house foundation. The swing and critical rotating speed of an actual generator set shaft system are calculated. The simulated results of the generator set indicate that the coupling vibration model and calculation method presented in this paper are suitable for stability analysis of the water turbine generator set.

New development of sets equipment technologies for coal mine longwall face in China

Background of the development and achievement on sets equipment technologies for coal mine longwall face in China was reviewed initially. On the theoretical side, a coupling model of hydraulic support and surrounding rock, support pa- rameters optimization and threedimensional （3D） dynamic design method were presented. On the practical side, this paper out lined some of practical issues and discussed some relative methods and technologies. In thin seam coal longwall mining, how to lower equipment height is the first problem that should be solved. Roof pressure regularity, control of rooffall and collapse, and hydraulic support stability were investigated preferentially in 5-7 m coal seam longwall mining. The application of equip- ment for longwall mining with 5-7 m cutting height in China was concluded. The characteristics of full-mechanized top coal caving for extra thick seam coal were presented. The automation of top-caving hydraulic support and relevant equipment have achieved important breakthrough. At the end of this paper, further development of China＇s coal industry and longwall mining technologies and equipment were prospected in brief. This paper gives readers a comprehensive understanding of China＇s coal mine longwall face equipment technologies. It will give help to other countries on its coal mining development.