期刊文献+
共找到1,435篇文章
< 1 2 72 >
每页显示 20 50 100
LÉVY AREA ANALYSIS AND PARAMETER ESTIMATION FOR FOU PROCESSES VIA NON-GEOMETRIC ROUGH PATH THEORY
1
作者 Zhongmin QIAN Xingcheng XU 《Acta Mathematica Scientia》 SCIE CSCD 2024年第5期1609-1638,共30页
This paper addresses the estimation problem of an unknown drift parameter matrix for a fractional Ornstein-Uhlenbeck process in a multi-dimensional setting.To tackle this problem,we propose a novel approach based on r... This paper addresses the estimation problem of an unknown drift parameter matrix for a fractional Ornstein-Uhlenbeck process in a multi-dimensional setting.To tackle this problem,we propose a novel approach based on rough path theory that allows us to construct pathwise rough path estimators from both continuous and discrete observations of a single path.Our approach is particularly suitable for high-frequency data.To formulate the parameter estimators,we introduce a theory of pathwise Itôintegrals with respect to fractional Brownian motion.By establishing the regularity of fractional Ornstein-Uhlenbeck processes and analyzing the long-term behavior of the associated Lévy area processes,we demonstrate that our estimators are strongly consistent and pathwise stable.Our findings offer a new perspective on estimating the drift parameter matrix for fractional Ornstein-Uhlenbeck processes in multi-dimensional settings,and may have practical implications for fields including finance,economics,and engineering. 展开更多
关键词 Itôintegration Lévy area non-geometric rough path fOU processes pathwise stability long time asymptotic high-frequency data
下载PDF
Towards the processing breakdown of syntactic garden path phenomenon: A semantic perspective of natural language expert system 被引量:1
2
作者 DU Jia-li YU Ping-fang +1 位作者 XU Jing ZHAO Hong-yan 《通讯和计算机(中英文版)》 2008年第11期53-61,共9页
关键词 数据库 语言学 计算机技术 语义
下载PDF
The inheritance path research of the processing of Chinese materia medica in Anguo herbs market 被引量:2
3
作者 Ying Chen Li-Na Zhang +4 位作者 Yu-Hui Ma Miao-Miao Lin Xing Zhang Yu Wang Guo-Wei Zhang 《TMR Theory and Hypothesis》 2019年第1期128-134,共7页
Anguo,known as Qizhou in ancient time,its herbs industry began in Song Dynasty,boomed in Ming,and flourished in Qing.During the development of Qizhou herbs industry,a number of special processing techniques of Chinese... Anguo,known as Qizhou in ancient time,its herbs industry began in Song Dynasty,boomed in Ming,and flourished in Qing.During the development of Qizhou herbs industry,a number of special processing techniques of Chinese Materia Medicine were produced."Qizhou's Four Uniqueness",of which,the most representative medicine includes"Hundred pieces areca","Cicada feather of Qingxia","Yunpian deer antler"and"Pound Rhinoceros unicornis L".To investigate the present inheritance situation of the traditional processing technology of Chinese Materia Medicine in Anguo herbs market,we will consult literature including the ancient books and records,Anguo local chronicles and visit the inheritors of the traditional processing technology in Anguo,and research the processing technology historical origin.This study aims to create the Anguo herbs cultural card,and enrich the cultural heritage of Chinese medicine industry of Anguo country even Hebei province. 展开更多
关键词 Qizhou's Four UNIQUENESS processING of Chinese Materia Medicine Anguo HERBS MARKET INHERITANCE path
下载PDF
Tracy-Widom distribution, Airy2 process and its sample path properties
4
作者 SU Zhong-gen LEI Yu-huan SHEN Tian 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2021年第1期128-158,共31页
Tracy-Widom distribution was rst discovered in the study of largest eigenvalues of high dimensional Gaussian unitary ensembles(GUE),and since then it has appeared in a number of apparently distinct research elds.It is... Tracy-Widom distribution was rst discovered in the study of largest eigenvalues of high dimensional Gaussian unitary ensembles(GUE),and since then it has appeared in a number of apparently distinct research elds.It is believed that Tracy-Widom distribution have a universal feature like classic normal distribution.Airy2 process is de ned through nite dimensional distributions with Tracy-Widom distribution as its marginal distributions.In this introductory survey,we will briey review some basic notions,intuitive background and fundamental properties concerning Tracy-Widom distribution and Airy2 process.For sake of reading,the paper starts with some simple and well-known facts about normal distributions,Gaussian processes and their sample path properties. 展开更多
关键词 Airy2 process Dyson Brownian motion Tracy-Widom distribution sample path property.
下载PDF
Path-dependent speciation in dynamic fitness landscapes
5
作者 Min-Lan Li Chao Wang Rui-Wu Wang 《Zoological Research(Diversity and Conservation)》 2024年第2期133-140,共8页
Species is a fundamental concept in evolutionary biology and biodiversity.However,existing species definitions are often influenced by artificial factors or are challenging in practical application,leading to confusio... Species is a fundamental concept in evolutionary biology and biodiversity.However,existing species definitions are often influenced by artificial factors or are challenging in practical application,leading to confusion in species classification.Due to uncertain environmental changes and random genetic drift,the fitness expectations of a population may shift,causing species to evolve to a new evolutionary state based on their current instantaneous fitness within a dynamic fitness landscape.This contrasts with the classic static fitness landscape,where fitness expectations are constant.In a dynamic fitness landscape,speciation may exhibit path dependence,where the evolution of traits follows a probabilistic path,creating feedback that shapes evolutionary trajectories.The path-dependent evolutionary mechanism suggests that species survival within an ecosystem is not directly determined by their fitness but by the probability of their evolutionary pathways.This model also indicates that species can coexist with varying probabilities under limited environmental pressures.Consequently,new species,cryptic species,or sympatric species may emerge via path-dependent evolutionary processes.Within this framework,we developed a mathematical species concept,which may guide future species classification methodologies. 展开更多
关键词 BIODIVERSITY Ecological/evolutionary model Fitness landscape Stochastic process path dependence
下载PDF
Fuzzy Q learning algorithm for dual-aircraft path planning to cooperatively detect targets by passive radars 被引量:6
6
作者 Xiang Gao Yangwang Fang Youli Wu 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2013年第5期800-810,共11页
The problem of passive detection discussed in this paper involves searching and locating an aerial emitter by dualaircraft using passive radars. In order to improve the detection probability and accuracy, a fuzzy Q le... The problem of passive detection discussed in this paper involves searching and locating an aerial emitter by dualaircraft using passive radars. In order to improve the detection probability and accuracy, a fuzzy Q learning algorithrn for dual-aircraft flight path planning is proposed. The passive detection task model of the dual-aircraft is set up based on the partition of the target active radar's radiation area. The problem is formulated as a Markov decision process (MDP) by using the fuzzy theory to make a generalization of the state space and defining the transition functions, action space and reward function properly. Details of the path planning algorithm are presented. Simulation results indicate that the algorithm can provide adaptive strategies for dual-aircraft to control their flight paths to detect a non-maneuvering or maneu- vering target. 展开更多
关键词 Markov decision process (MDP) fuzzy Q learning dual-aircraft coordination path planning passive detection.
下载PDF
Research on Opportunity-Driven Redesign Process to Cooperate With Training Innovative Engineers in China 被引量:3
7
作者 Run-Hua Tan Ya-Fan Dong +1 位作者 Bo-Jun Yang Peng Zhang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2018年第4期148-159,共12页
Many design engineers in cross-domain industries have attended training classes of TRIZ to improve their innovative abilities in China. Most of them are successful, but others are not. So the latest target of the trai... Many design engineers in cross-domain industries have attended training classes of TRIZ to improve their innovative abilities in China. Most of them are successful, but others are not. So the latest target of the trainers is to improve the training process used now in industry in China and to make the engineers to understand the basic principles of TRIZ better. Based on the mass-engineer-oriented training model(MEOTM) and mechanical engineers’ design cases, a relationship between managing activities about the opportunities for innovation and the training process is set up. It is shown that the inventive problems come first from opportunity searching for engineers. A training and gate system for evaluation is developed to involve the managing activities of the companies in the training process. Then comparison between the general analogous process and the application of TRIZ is made, which shows the advantages and depth principles of TRIZ for the engineers to apply them confidently. Lastly a new process is formed in which opportunity searching, engineers training, inventive problems identifying and solving,and three redesign paths are connected seamlessly. The research proposes an opportunity-driven redesign path that cooperates the training and opportunity searching, which will be applied in future training classes to make more and more engineers to follow. 展开更多
关键词 TRIZ Mass-engineer oriented training model Redesign path Opportunity-driven Redesign process
下载PDF
Modeling of UAV path planning based on IMM under POMDP framework 被引量:4
8
作者 YANG Qiming ZHANG Jiandong SHI Guoqing 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2019年第3期545-554,共10页
In order to enhance the capability of tracking targets autonomously of unmanned aerial vehicle (UAV), the partially observable Markov decision process (POMDP) model for UAV path planning is established based on the PO... In order to enhance the capability of tracking targets autonomously of unmanned aerial vehicle (UAV), the partially observable Markov decision process (POMDP) model for UAV path planning is established based on the POMDP framework. The elements of the POMDP model are analyzed and described. The state transfer law in the model can be described by the method of interactive multiple model (IMM) due to the diversity of the target motion law, which is used to switch the motion model to accommodate target maneuvers, and hence improving the tracking accuracy. The simulation results show that the model can achieve efficient planning for the UAV route, and effective tracking for the target. Furthermore, the path planned by this model is more reasonable and efficient than that by using the single state transition law. 展开更多
关键词 PARTIALLY OBSERVABLE MARKOV decision process (POMDP) interactive multiple model (IMM) filtering path planning target tracking state transfer law
下载PDF
Yanshanian Magma-Tectonic-Metallogenic Belt in East China of Circum-Pacific Domain(Ⅰ):Igneous Rocks and Orogenic Processes 被引量:3
9
作者 Deng Jinfu Mo Xuanxue Zhao Hailing Luo Zhaohua Zhao Guochun Department of Geology and Mineral Resources, China University of Geosciences, Beijing 100083 《Journal of Earth Science》 SCIE CAS CSCD 1999年第1期25-28,共4页
Yanshanian igneous rocks in the East China, on an orogenic belt scale, are characterized by the continental marginal arc in petrology and geochemistry as Andes and West USA, except for the Hercyn type biotite two mi... Yanshanian igneous rocks in the East China, on an orogenic belt scale, are characterized by the continental marginal arc in petrology and geochemistry as Andes and West USA, except for the Hercyn type biotite two mica muscovite granite belt in the Nanling region. Three segments of the Yanshanian igneous rocks along the belt are recognized. In terms of magma tectonic event sequence, the north, middle and south segments have counter clockwise (ccw), clockwise (cw) and ccw+cw pTt paths of the orogenic process, respectively. A genetic model of the lithospheric delamination (loss of the lithospheric root in about 120 km) in combination with the oceanic subduction for the Yanshanian Andes like orogenic belt and both the crust and lithosphere thickening for the Yanshanian Hercyn type Nanling orogenic belt in the East China is suggested. 展开更多
关键词 Yanshanian igneous rocks orogenic processes ccw/cw pTt path East China.
下载PDF
Path Selection in Disaster Response Management Based on Q-learning 被引量:3
10
作者 Zhao-Pin Su Jian-Guo Jiang +1 位作者 Chang-Yong Liang2' 3 Guo-Fu Zhang Guo-Fu Zhang 《International Journal of Automation and computing》 EI 2011年第1期100-106,共7页
Suitable rescue path selection is very important to rescue lives and reduce the loss of disasters, and has been a key issue in the field of disaster response management. In this paper, we present a path selection algo... Suitable rescue path selection is very important to rescue lives and reduce the loss of disasters, and has been a key issue in the field of disaster response management. In this paper, we present a path selection algorithm based on Q-learning for disaster response applications. We assume that a rescue team is an agent, which is operating in a dynamic and dangerous environment and needs to find a safe and short path in the least time. We first propose a path selection model for disaster response management, and deduce that path selection based on our model is a Markov decision process. Then, we introduce Q-learning and design strategies for action selection and to avoid cyclic path. Finally, experimental results show that our algorithm can find a safe and short path in the dynamic and dangerous environment, which can provide a specific and significant reference for practical management in disaster response applications. 展开更多
关键词 Disaster response management path selection AGENT SELF-ORGANIZING Markov decision process Q-learning.
下载PDF
Classification and Analysis of Tube Hydroforming Processes with Respect to Adaptive FEM Simulations 被引量:2
11
作者 Sebastian MOTSCH Matteo STRANO 《厦门大学学报(自然科学版)》 CAS CSCD 北大核心 2002年第S1期139-140,共2页
Tube hydroforming process is a relative new process f or production of structural parts of low weight and high rigidity. The successfu lness of the process depends largely on the a proper selection of loading path w h... Tube hydroforming process is a relative new process f or production of structural parts of low weight and high rigidity. The successfu lness of the process depends largely on the a proper selection of loading path w hich is axial feeding distance as related to the applied internal pressure. Due to the complicated nature of plastic deformation, a optimum loading path which w ill guarantee good hydroformed parts free of winkle and fracture has often to be determined by finite element analysis. In order to save trials and errors, adap tive FEM simulation method has been developed. To effectively apply the adaptive simulation method, we have to know the applicability of the method. In this pap er, a classification of tube hydroforming (THF) processes based on sensitivity to loading parameters has been suggested. Characteristics of the classification have been analyzed in terms of failure mode, dominant loading parameters and th eir working windows. It was discussed that the so called pressure dominant THF p rocess is the most difficult process for both simulation in FEM analysis and pra ctical operation in real manufacturing situation. To effectively find out the op timum loading path for pressure dominant THF process, adaptive FEM simulation st rategies are mostly needed. 展开更多
关键词 tube hydroforming process classification loadin g path adaptive simulation
下载PDF
ENTROPY PRODUCTION RATE OF THE MINIMAL DIFFUSION PROCESS 被引量:1
12
作者 章复熹 钱敏 《Acta Mathematica Scientia》 SCIE CSCD 2007年第1期145-152,共8页
The entropy production rate of stationary minimal diffusion processes with smooth coefficients is calculated. As a byproduct, the continuity of paths of the minimal diffusion processes is discussed, and that the point... The entropy production rate of stationary minimal diffusion processes with smooth coefficients is calculated. As a byproduct, the continuity of paths of the minimal diffusion processes is discussed, and that the point at infinity is absorbing is proved. 展开更多
关键词 Minimal diffusion process entropy production rate continuous path
下载PDF
An Improved Immune Algorithm for Solving Path Optimization Problem in Deep Immune Learning of Gene Network 被引量:1
13
作者 Tao Gong Mengyuan Wang 《Journal of Computer and Communications》 2019年第12期166-174,共9页
In order to overcome some defects of the traditional immune algorithm, the immune algorithm was improved for solving a path optimization problem in deep immune learning of a gene network. Firstly, the diversity of the... In order to overcome some defects of the traditional immune algorithm, the immune algorithm was improved for solving a path optimization problem in deep immune learning of a gene network. Firstly, the diversity of the solution population was enhanced in the evolution process by improving the memory cell processing method. Moreover, effective gene information was dynamically extracted from the genes of the excellent antibodies to make good vaccines in the process of immune evolution. Worse antibodies were optimized by vaccinating these antibodies, and the convergence of the immune algorithm to the optimal solution was improved. Finally, the feasibility of the improved immune algorithm was verified in the experimental simulation for solving the classic NP problem in deep immune learning of the gene network. 展开更多
关键词 IMPROVED IMMUNE Algorithm path Optimization Memory Cell processing VACCINE
下载PDF
Dynamic A^*path finding algorithm and 3D lidar based obstacle avoidance strategy for autonomous vehicles 被引量:3
14
作者 Wang Xiaohua Ma Pin +1 位作者 Wang Hua Li Li 《High Technology Letters》 EI CAS 2020年第4期383-389,共7页
This paper presents a novel dynamic A^*path finding algorithm and 3D lidar based local obstacle avoidance strategy for an autonomous vehicle.3D point cloud data is collected and analyzed in real time.Local obstacles a... This paper presents a novel dynamic A^*path finding algorithm and 3D lidar based local obstacle avoidance strategy for an autonomous vehicle.3D point cloud data is collected and analyzed in real time.Local obstacles are detected online and a 2D local obstacle grid map is constructed at 10 Hz/s.The A^*path finding algorithm is employed to generate a local path in this local obstacle grid map by considering both the target position and obstacles.The vehicle avoids obstacles under the guidance of the generated local path.Experiment results have shown the effectiveness of the obstacle avoidance navigation algorithm proposed. 展开更多
关键词 autonomous navigation local obstacle avoidance dynamic A*path finding algorithm point cloud processing local obstacle map
下载PDF
An Integrated Approach to Oscillation Propagation Identification and Source Locating in Process Multi-loop Systems 被引量:1
15
作者 曹稼斌 张亮 +1 位作者 郑建荣 夏春明 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2011年第6期999-1008,共10页
An integrated method for identifying the propagation of multi-loop process oscillations and their source location is proposed in this paper. Oscillatory process loop variables are automatically selected based on the c... An integrated method for identifying the propagation of multi-loop process oscillations and their source location is proposed in this paper. Oscillatory process loop variables are automatically selected based on the component-related ratio index and a mixing matrix, both of which are obtained in data preprocessing by spectral independent component analysis. The complex causality among oscillatory process variables is then revealed by Granger causality test and is visualized in the form of causality diagram. The simplification of causal connectivity in the diagram is performed according to the understanding of process knowledge and the final simplest causality diagram, which represents the main oscillation propagation paths, is achieved by the automated cutting-off thresh-old search, with which less significant causality pathways are filtered out. The source of the oscillation disturbance can be identified intuitively through the final causality diagram. Both simulated and real plant data tests are presented to demonstrate the effectiveness and feasibility of the proposed method. 展开更多
关键词 multi-loop system process oscillation spectral independent component analysis Granger causality test causality diagram propagation path simplification source locating
下载PDF
Maximal speed of particles in super-Lévy process
16
作者 林正炎 程宗毛 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2008年第4期517-525,共9页
We introduce a super-Lévy process and study maximal speed of all particles in the range and the support of the super-Lévy process. The state of historical super-Lévy process is a measure on the set of p... We introduce a super-Lévy process and study maximal speed of all particles in the range and the support of the super-Lévy process. The state of historical super-Lévy process is a measure on the set of paths. We study the maximal speed of all particles during a given time period, which turns out to be a function of the packing dimension of the time period. We calculate the Hausdorff dimension of the set of a-fast paths in the support and the range of the historical super-Lévy process. 展开更多
关键词 super-Lévy process modulus of continuity Hausdorff dimension Lévy process a-fast path Brownian motion
下载PDF
Chinese Childrenswear Brand Development Path Based on Differentiated Positioning
17
作者 HOU Fengxian 《Journal of Donghua University(English Edition)》 EI CAS 2019年第2期198-204,共7页
Sorting and collecting the data by questionnaire survey and literature analysis,the childrenswear brand elemental analysis is completed.The development goal of differentiated positioning of Chinese childrenswear brand... Sorting and collecting the data by questionnaire survey and literature analysis,the childrenswear brand elemental analysis is completed.The development goal of differentiated positioning of Chinese childrenswear brands is decided.Four modules which influence the brand differentiated development were extracted to establish the hierarchical analysis framework for the differentiated positioning development of Chinese childrenswear brand.Judgment matrix diagram is constructed by using the analytic hierarchy process(AHP).According to the data analysis and judgment,the core elements,basic elements and auxiliary elements are identified which support the development of differentiated positioning of Chinese childrenswear brands.The clear development path of differentiated positioning of Chinese childrenswear brands is formed,namely to enhance the core essential factors as the key point,to grasp the elements’spirit exactly in differentiated positioning of brand style,childrenswear color feature,green and security of products quality and retail prices which influence the brand differentiated development.The Chinese existing technical advantages was given full play by providing the basic support for the differentiated development of childrenswear brands.Auxiliary elements were heleped to grow by making auxiliary elements play a greater role.The goal was achieved to improve the market competitiveness by development of differentiated positioning of Chinese childrenswear brands. 展开更多
关键词 DIFFERENTIATED positioning childrenswear brands ANALYTIC HIERARCHY process(AHP) element development path
下载PDF
The Metamorphic and Deformational History of a Continental Collision Zone and its Geodynamic Process——as Evidenced by Qinling Complex,Western Henan,China
18
作者 You Zhendong Han Yujing Suo Shutian Chen Nensong Zhong ZenqiuDepartment of Geology, China University of Geosciences, Wuhan 430074 《Journal of Earth Science》 SCIE CAS CSCD 1990年第1期62-76,共15页
The Qinling orogenic belt is a collision zone between the North China and Yangtze cratons. The Qinling Complex is a Precambrian metamorphic complex, developed in the inner zone of the orogenic belt , which records the... The Qinling orogenic belt is a collision zone between the North China and Yangtze cratons. The Qinling Complex is a Precambrian metamorphic complex, developed in the inner zone of the orogenic belt , which records the metamorphic and deformational history and PTt path of the regional meta-morphism of the collision zone . The present paper studies the metamorphic and deformational history and the PTt path of various tectono-metamorphic cycles in order to describe the geodynamic processes prevailing in that part of the Qinling orogenic belt since Proterozoic.The tectonometamorphic history and evolution of the Qinling Complex is divided into two stages: the stage of formation and the stage of modification During the stage of formation dated as Proterozoic,three deformational sequences are recognized. The amphibolite facies regional metamorphism is earlier than or synchronous with the first or second phase of folding. Three metamorphic zones, i.e. And-Ms ,Sil- Ms, Sil Kfs are delimited. During the stage of modification , the emplacement of Caledonian granite , superimposed thermal aureole (garnet K feldspar zone )and the development of ductile shear zones are major events.Metamorphic reactions are reconstructed in terms of analysis of re-equilibrium textures. Geothermobarometric calculations are conducted to calibrate the PT conditions of metamorphism .The metamorphic PTt paths have been estabh'shed. The PTt path of the Proterozoic tectonometamorphic cycle shows a clockwise pattern and is characterized by prominent decompression. The PTt path of the Caledonian tectonometamorphic cycle is characterized first by PT rising ,then isothermal decompression (rapid uplift), and finally by isobaric cooling The PTt path of the two tectonometamorphic cycles evidence the geodynamic processes: two major stages of collision and uplift in the Proterozoic and Caledonian Hercynian periods, respectively, during the evolution of Qinling orogenic belt. 展开更多
关键词 Qinling orogenic belt metamorphic history tectonomet- am orphic cycle PTt path geodynamic processes .
下载PDF
Stochastic Process Optimization Technique
19
作者 Hiroaki Yoshida Katsuhito Yamaguchi Yoshio Ishikawa 《Applied Mathematics》 2014年第19期3079-3090,共12页
The conventional optimization methods were generally based on a deterministic approach, since their purpose is to find out an accurate solution. However, when the solution space is extremely narrowed as a result of se... The conventional optimization methods were generally based on a deterministic approach, since their purpose is to find out an accurate solution. However, when the solution space is extremely narrowed as a result of setting many inequality constraints, an ingenious scheme based on experience may be needed. Similarly, parameters must be adjusted with solution search algorithms when nonlinearity of the problem is strong, because the risk of falling into local solution is high. Thus, we here propose a new method in which the optimization problem is replaced with stochastic process based on path integral techniques used in quantum mechanics and an approximate value of optimal solution is calculated as an expected value instead of accurate value. It was checked through some optimization problems that this method using stochastic process is effective. We call this new optimization method “stochastic process optimization technique (SPOT)”. It is expected that this method will enable efficient optimization by avoiding the above difficulties. In this report, a new optimization method based on a stochastic process is formulated, and several calculation examples are shown to prove its effectiveness as a method to obtain approximate solution for optimization problems. 展开更多
关键词 Optimization STOCHASTIC process path INTEGRAL EXPECTED VALUE Quantum MECHANICS
下载PDF
Studying Formability Limits By Combining Conventional and Incremental Sheet Forming Process
20
作者 Fabio Andre Lora Daniel Fritzen +1 位作者 Ricardo Alves de Sousa Lirio Schaffer 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2021年第4期78-89,共12页
In this work it is assessed the potential of combining conventional and incremental sheet forming processes in a same sheet of metal.This so-called hybrid forming approach is performed through the manufacture of a pre... In this work it is assessed the potential of combining conventional and incremental sheet forming processes in a same sheet of metal.This so-called hybrid forming approach is performed through the manufacture of a pre-forming by conventional forming,followed by incremental sheet forming.The main objective is analyzing strain evolution.The pre-forming induced in the conventional forming stage will determine the strain paths,directly influencing the strains produced by the incremental process.To conduct the study,in the conventional processes,strains were imposed in three different ways with distinct true strains.At the incremental stage,the pyramid strategy was adopted with different wall slopes.From the experiments,the true strains and the final geometries were analyzed.Numerical simulation was also employed for the sake of comparison and correlation with the measured data.It could be observed that single-stretch pre-strain was directly proportional to the maximum incremental strains achieved,whereas samples subjected to biaxial pre-strain influenced the formability according to the degree of pre-strain applied.Pre-strain driven by the prior deep-drawing operation did not result,in this particular geometry,in increased formability. 展开更多
关键词 Hybrid forming process Incremental sheet forming Strain paths Numerical simulation
下载PDF
上一页 1 2 72 下一页 到第
使用帮助 返回顶部