基于PHF(permeability-based hydraulic fracture)模型,采用水平集方法(level set method,LSM)描述材料边界分布,并用多尺度方法MT模型,对材料有效参数进行均匀化,建立适用于考虑非均质岩石材料细观界面特征分布与水力裂缝动态发展过程...基于PHF(permeability-based hydraulic fracture)模型,采用水平集方法(level set method,LSM)描述材料边界分布,并用多尺度方法MT模型,对材料有效参数进行均匀化,建立适用于考虑非均质岩石材料细观界面特征分布与水力裂缝动态发展过程的PHF-LSM-MT数值计算模型.该模型解决了已有PHF-LSM模型无法精确描述积分点作用范围内细观尺度材料分布特征的问题.通过比较包裹体几何分布和体积分数影响下的有效弹性参数,验证了采用MT模型均匀化细观特征的可行性;在此基础上,对非均质岩石水力裂缝发展过程进行研究,得到了考虑细观界面特征情况下的裂缝发展过程,探讨了等效开裂区域影响范围内关键位置的水压力变化特征和应力路径发展过程.展开更多
Knowledge-Based Engineering （KBE） is introduced into the ship structural design in this paper. From the implementation of KBE, the design solutions for both Rules Design Method （RDM） and Interpolation Design Meth...Knowledge-Based Engineering （KBE） is introduced into the ship structural design in this paper. From the implementation of KBE, the design solutions for both Rules Design Method （RDM） and Interpolation Design Method （IDM） are generated. The corresponding Finite Element （FE） models are generated. Topological design of the longitudinal structures is studied where the Gaussian Process （GP） is employed to build the surrogate model for FE analysis. Multi-objective optimization methods inspired by Pareto Front are used to reduce the design tank weight and outer surface area simultaneously. Additionally, an enhanced Level Set Method （LSM） which employs implicit algorithm is applied to the topological design of typical bracket plate which is used extensively in ship structures. Two different sets of boundary conditions are considered. The proposed methods show satisfactory efficiency and accuracy.展开更多
To implement the prediction of the logistics demand capacity of a certain region,a comprehensive index system is constructed,which is composed of freight volume and other eight relevant economic indices,such as gross ...To implement the prediction of the logistics demand capacity of a certain region,a comprehensive index system is constructed,which is composed of freight volume and other eight relevant economic indices,such as gross domestic product(GDP),consumer price index(CPI),total import and export volume,port's cargo throughput,total retail sales of consumer goods,total fixed asset investment,highway mileage,and resident population,to form the foundation for the model calculation.Based on the least square method(LSM)to fit the parameters,the study obtains an accurate mathematical model and predicts the changes of each index in the next five years.Using artificial intelligence software,the research establishes the logistics demand model of multi-layer perceptron(MLP)neural network,makes an empirical analysis on the logistics demand of Quanzhou City,and predicts its logistics demand in the next five years,which provides some references for formulating logistics planning and development strategy.展开更多
智能化科研(AI4R)是科研方法的重大变革。提出科技界不仅要关注科学智能(AI for Science,AI4S),更要重视技术智能(AI for Technology,AI4T);不仅要关注大语言模型(LLM),更要重视大科学模型(LSM)。同时提出,人工智能的突破主要不是靠大算...智能化科研(AI4R)是科研方法的重大变革。提出科技界不仅要关注科学智能(AI for Science,AI4S),更要重视技术智能(AI for Technology,AI4T);不仅要关注大语言模型(LLM),更要重视大科学模型(LSM)。同时提出,人工智能的突破主要不是靠大算力,而是计算模型的转变,中国应当争取在基础模型上做出颠覆性的创新;智能化科研适合做复杂问题的组合搜索,神经网络模型也许已接近能处理困难问题的复杂度阈值点;智能化科研的一种趋势是放弃绝对性,拥抱不确定性,一定时期内要适当容忍“黑盒模型”。展开更多
A sink vortex is a common physical phenomenon in continuous casting,chemical extraction,water conservancy,and other industrial processes,and often causes damage and loss in production.Therefore,the real-time monitorin...A sink vortex is a common physical phenomenon in continuous casting,chemical extraction,water conservancy,and other industrial processes,and often causes damage and loss in production.Therefore,the real-time monitoring of the sink vortex state is important for improving industrial production efficiency.However,its suction-extraction phenomenon and shock vibration characteristics in the course of its formation are complex mechanical dynamic factors for flow field state monitoring.To address this issue,we set up a multi-physics model using the level set method(LSM)for a free sink vortex to study the two-phase interaction mechanism.Then,a fluid–solid coupling dynamic model was deduced to investigate the shock vibration characteristics and reveal the transition mechanism of the critical flow state.The numerical results show that the coupling energy shock induces a pressure oscillation phenomenon,which appears to be a transient enhancement of vibration at the vortex penetration state.The central part of the transient enhancement signal is a high-frequency signal.Based on the dynamic coupling model,an experimental observation platform was established to verify the accuracy of the numerical results.The water-model experiment results were accordant with the numerical results.The above results provide a reference for fluid state recognition and active vortex control for industrial monitoring systems,such as those in aerospace pipe transport,hydropower generation,and microfluidic devices.展开更多
为精确模拟含软弱夹层的隧道爆破应力波传播过程,探究爆破振动穿越软弱层前后的动力响应规律,本研究基于JHB-4D-LSM(Johnson-Holmquist-Beissel-four-dimensional lattice spring model)连续-非连续方法,建立单孔爆破数值模型,重点分析...为精确模拟含软弱夹层的隧道爆破应力波传播过程,探究爆破振动穿越软弱层前后的动力响应规律,本研究基于JHB-4D-LSM(Johnson-Holmquist-Beissel-four-dimensional lattice spring model)连续-非连续方法,建立单孔爆破数值模型,重点分析不同爆破距离、夹层厚度及倾角等因素的影响。结果表明:基于JHB-4D-LSM模型模拟了隧道爆破应力波传播过程,计算结果与LS-DYNA模拟结果吻合较好,验证了该方法的有效性。软弱夹层的迎波面岩体局部应力集中、峰值应力增加,背波面岩体应力峰值降低;说明夹层具有双重作用,应波面应力增强及背波面应力衰减,且双重作用效应随着软弱夹层厚度的增加,呈正相关的关系,对施工安全控制具有指导意义。软弱夹层与炮孔距离越小,夹层迎波面岩体应力集中现象越明显,当两者的距离大于30 cm时,软弱夹层对应力传播的影响减小;软弱夹层倾角对爆破应力波传播的影响,主要取决于炮孔与软弱夹层的垂直距离,垂直距离越小,炮孔附近岩体的应力峰值越高,应力阻隔效应越明显。本研究结果为软弱层发育地区隧道爆破振动控制技术的优化提供了借鉴和参考。展开更多
文摘基于PHF(permeability-based hydraulic fracture)模型,采用水平集方法(level set method,LSM)描述材料边界分布,并用多尺度方法MT模型,对材料有效参数进行均匀化,建立适用于考虑非均质岩石材料细观界面特征分布与水力裂缝动态发展过程的PHF-LSM-MT数值计算模型.该模型解决了已有PHF-LSM模型无法精确描述积分点作用范围内细观尺度材料分布特征的问题.通过比较包裹体几何分布和体积分数影响下的有效弹性参数,验证了采用MT模型均匀化细观特征的可行性;在此基础上,对非均质岩石水力裂缝发展过程进行研究,得到了考虑细观界面特征情况下的裂缝发展过程,探讨了等效开裂区域影响范围内关键位置的水压力变化特征和应力路径发展过程.
基金financially supported by the Project of Ministry of Education and Finance of China(Grant Nos.200512 and 201335)the Project of the State Key Laboratory of Ocean Engineering,Shanghai Jiao Tong University(Grant No.GKZD010053-10)
文摘Knowledge-Based Engineering （KBE） is introduced into the ship structural design in this paper. From the implementation of KBE, the design solutions for both Rules Design Method （RDM） and Interpolation Design Method （IDM） are generated. The corresponding Finite Element （FE） models are generated. Topological design of the longitudinal structures is studied where the Gaussian Process （GP） is employed to build the surrogate model for FE analysis. Multi-objective optimization methods inspired by Pareto Front are used to reduce the design tank weight and outer surface area simultaneously. Additionally, an enhanced Level Set Method （LSM） which employs implicit algorithm is applied to the topological design of typical bracket plate which is used extensively in ship structures. Two different sets of boundary conditions are considered. The proposed methods show satisfactory efficiency and accuracy.
基金Educational Research Project of Social Science for Young and Middle Aged Teachers in Fujian Province,China(No.JAS19371)Social Science Research Project of Education Department of Fujian Province,China(No.JAS160571)Key Project of Education and Teaching Reform of Undergraduate Universities in Fujian Province,China(No.FBJG20190130)。
文摘To implement the prediction of the logistics demand capacity of a certain region,a comprehensive index system is constructed,which is composed of freight volume and other eight relevant economic indices,such as gross domestic product(GDP),consumer price index(CPI),total import and export volume,port's cargo throughput,total retail sales of consumer goods,total fixed asset investment,highway mileage,and resident population,to form the foundation for the model calculation.Based on the least square method(LSM)to fit the parameters,the study obtains an accurate mathematical model and predicts the changes of each index in the next five years.Using artificial intelligence software,the research establishes the logistics demand model of multi-layer perceptron(MLP)neural network,makes an empirical analysis on the logistics demand of Quanzhou City,and predicts its logistics demand in the next five years,which provides some references for formulating logistics planning and development strategy.
文摘智能化科研(AI4R)是科研方法的重大变革。提出科技界不仅要关注科学智能(AI for Science,AI4S),更要重视技术智能(AI for Technology,AI4T);不仅要关注大语言模型(LLM),更要重视大科学模型(LSM)。同时提出,人工智能的突破主要不是靠大算力,而是计算模型的转变,中国应当争取在基础模型上做出颠覆性的创新;智能化科研适合做复杂问题的组合搜索,神经网络模型也许已接近能处理困难问题的复杂度阈值点;智能化科研的一种趋势是放弃绝对性,拥抱不确定性,一定时期内要适当容忍“黑盒模型”。
基金supported by the National Natural Science Foundation of China(Nos.52175124 and 52305139)the Zhejiang Provincial Natural Science Foundation of China(No.LZ21E050003)+1 种基金the Fundamental Research Funds for the Zhejiang Provincial Universities(No.RF-C2020004)the Open Foundation of the State Key Laboratory of Fluid Power and Mechatronic Systems(No.GZKF-202125),China.
文摘A sink vortex is a common physical phenomenon in continuous casting,chemical extraction,water conservancy,and other industrial processes,and often causes damage and loss in production.Therefore,the real-time monitoring of the sink vortex state is important for improving industrial production efficiency.However,its suction-extraction phenomenon and shock vibration characteristics in the course of its formation are complex mechanical dynamic factors for flow field state monitoring.To address this issue,we set up a multi-physics model using the level set method(LSM)for a free sink vortex to study the two-phase interaction mechanism.Then,a fluid–solid coupling dynamic model was deduced to investigate the shock vibration characteristics and reveal the transition mechanism of the critical flow state.The numerical results show that the coupling energy shock induces a pressure oscillation phenomenon,which appears to be a transient enhancement of vibration at the vortex penetration state.The central part of the transient enhancement signal is a high-frequency signal.Based on the dynamic coupling model,an experimental observation platform was established to verify the accuracy of the numerical results.The water-model experiment results were accordant with the numerical results.The above results provide a reference for fluid state recognition and active vortex control for industrial monitoring systems,such as those in aerospace pipe transport,hydropower generation,and microfluidic devices.
文摘为精确模拟含软弱夹层的隧道爆破应力波传播过程,探究爆破振动穿越软弱层前后的动力响应规律,本研究基于JHB-4D-LSM(Johnson-Holmquist-Beissel-four-dimensional lattice spring model)连续-非连续方法,建立单孔爆破数值模型,重点分析不同爆破距离、夹层厚度及倾角等因素的影响。结果表明:基于JHB-4D-LSM模型模拟了隧道爆破应力波传播过程,计算结果与LS-DYNA模拟结果吻合较好,验证了该方法的有效性。软弱夹层的迎波面岩体局部应力集中、峰值应力增加,背波面岩体应力峰值降低;说明夹层具有双重作用,应波面应力增强及背波面应力衰减,且双重作用效应随着软弱夹层厚度的增加,呈正相关的关系,对施工安全控制具有指导意义。软弱夹层与炮孔距离越小,夹层迎波面岩体应力集中现象越明显,当两者的距离大于30 cm时,软弱夹层对应力传播的影响减小;软弱夹层倾角对爆破应力波传播的影响,主要取决于炮孔与软弱夹层的垂直距离,垂直距离越小,炮孔附近岩体的应力峰值越高,应力阻隔效应越明显。本研究结果为软弱层发育地区隧道爆破振动控制技术的优化提供了借鉴和参考。
