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1.
The use of finite element analysis in the development of closed-die forging processes is widely established in industry. However, the simulated and the real workpiece dimensions differ from each other in a significant way, as the interactions between the forging process and the production machine are not adequately considered in the simulation. As a result, multi-stage dies in particular often need to undergo an experimental time-consuming optimization process on the production machine. In this paper a method is presented that allows the coupling of the forging simulation with external machine tool simulation systems and nonlinear-elastic press models in order to consider the interactions between the process and the machine, and to improve the accuracy of the forging simulation. This method of coupled simulation was integrated into a software tool and may be used for single-stage as well as for multi-stage processes in closed-die forging operations. It allows simulation-aided optimization of the dies as early as the design stage as well as individual adaptation to the particular production press well in advance of the test phase of the dies on the press. 相似文献
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Critical issues in the simulation of hot forming operations 总被引:1,自引:0,他引:1
The paper deals with the correlations that can be established in the numerical simulation of manufacturing process chains
among the process parameters, microstructure evolution, and properties of the final product. With the focus on process chains
applied to bulk and sheet metal parts where deformation is carried out in hot working conditions, the paper illustrates through
three application cases the role that the analysis of the microstructure evolution plays in the process chains simulations
and, in particular, in enhancing the capabilities of the models that are currently implemented in commercial FE codes for
predicting the properties of the final part. 相似文献
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Roland Larek Ekkard Brinksmeier Daniel Meyer Thorsten Pawletta Olaf Hagendorf 《Production Engineering》2011,5(5):575-579
Whereas in the past the sustainable use of resources and the reduction of waste have mainly been looked at from an ecological
point of view, resource efficiency recently becomes more and more an issue of cost saving as well. In manufacturing engineering
especially the reduction of power consumption of machine tools and production facilities is in the focus of industry, politics
and research. Before power consumption in machining processes can be reduced it is necessary to quantify the amount of energy
needed, to identify energy consumers and to determine the available degrees of freedom for an optimization. Simulation can
be an adequate alternative to the measurement of power consumption during machining operation. However, many of the available
simulation methods are not suitable for this task. This paper describes an approach based on the discrete-event simulation,
which is known mainly from the simulation of logistical systems. It has been adapted to model machining operations and to
generate workpiece-specific power consumption profiles and energy footprints. Two-axis turning in a CNC machining centre is
shown exemplary. The aim is to provide a basis for further applications such as the simulation, comparison and optimization
of power consumption in process chains and production systems in combination with logistical models. 相似文献
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A. C. Lewis S. M. Qidwai M. Jackson A. B. Geltmacher 《JOM Journal of the Minerals, Metals and Materials Society》2011,63(3):35-39
For the most comprehensive modeling and prediction of materials behavior at the microscale, experimentally measured three-dimensional
(3-D) microstructural datasets must be incorporated as initial input into computational models. Although the capability to
collect and store large amounts of 3-D microstructural data is advancing continuously, computational resources for the processing
and simulation can limit the amount of data that can be analyzed. Depending on the features and properties of interest, several
approaches can be applied to optimize processing, reduce the amount of data that needs to be simulated, and increase the efficiency
of simulations to maximize the statistical significance of microstructure analyses. This paper presents examples of four such
approaches to efficient integration of large 3-D datasets into modeling and simulations of mechanical behavior in an efficient
yet statistically significant manner. 相似文献
6.
散热器铝型材挤压的数值模拟 总被引:1,自引:0,他引:1
采用基于A-L-E算法的HyperXtrude软件,建立有限元分析模型,对散热器铝合金型材挤压过程进行了稳态流动仿真,获得了型材的位移分布和速度分布图,模拟结果与生产实际吻合较好;针对试模出现的问题,对出口速度分布和应力分布进行分析,提出在下模增加阻流台和修改工作带方案,有效地解决了初始模具设计中速度分布不均的问题;最后针对装配后型材平面度达不到要求这一缺陷,对模具工作带进行调整优化,用优化后的模其生产的型材可以装配使用. 相似文献
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Numerical simulation of various cross sectional workpieces using conventional deep drawing and hydroforming technologies 总被引:2,自引:0,他引:2
This study focuses on the determination of optimum sheet metal forming process and process parameters for various cross sectional workpieces by comparing the numerical results of high-pressure sheet metal forming, hydro-mechanical deep drawing (DD) and conventional DD simulations. Within the range of each cross section, depth, characteristic dimensions ratio and fillet radius have been altered systematically. Steel of types St14 and DC04 have been used as the specimen material in the numerical analyses and the experimental verification throughout the study. All numerical simulations have been carried out by using a dynamic–explicit commercial finite element code and an elasto-plastic material model. During the analyses each workpiece was simulated by the three competing processes. The results of analyses, such as sheet thickness distribution, necking, forming of radii etc., are used for assessing the success of each forming process alternative. The analyses revealed that depending on the workpiece geometry and dimensional properties certain processes are preferable for obtaining more satisfactory products. Working windows for each process have been established based on the analyzed parameters of the circular, elliptic, rectangular and square cross sectional product geometries. This data is expected to be useful for selecting the appropriate production process for a given workpiece geometry and understand the limits of each sheet metal forming processes. 相似文献
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Chih-Young Lin Wei-Hsin Huang Ming-Chang Jeng Ji-Liang Doong 《Journal of Materials Processing Technology》1997,70(1-3):9-16
The traditional design methods of assembly tolerance allocation are usually based on engineers' experience, or the worst on worst tolerance analysis (WOW) method, or the root sum square tolerance analysis (RSS) method. However, the above-mentioned methods, whilst used frequently in the analysis of a single-dimensional chain, are not suitable for the analysis of geometrical tolerance and multi-dimensional chains. Also, the relationship between tolerance and manufacturing cost is not considered and a suitable tolerance allocation based on minimum manufacturing cost can not be obtained. Some research works have applied linear or non-linear programming methods to optimize the tolerance allocation of each part in an assembly. However, the convergence of the solution is not ensured. The purpose of this study is to provide an integrated approach, including tolerance design, manufacturing cost analysis and multiple chains consideration, using the Monte Carlo method to optimize the tolerance allocation with minimum cost. The Monte Carlo method, a statistical simulation method, was used to simulate the dimension variance of each part and each dimensional chain. The contribution percentage of each part on each dimensional chain was calculated. Tolerance cost was chosen as an object function and the tolerance allocation model as a constraint condition, the optimum tolerances of each part being obtained by the iteration method. Results of computer simulation for several examples were compared with published data for demonstrating the feasibility of the proposed method. It can be concluded that the tolerance-allocation model combined with a tolerance-cost relationship can provide a very practical and useful approach for design engineers. 相似文献
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Analysis and simulation of the grinding process. Part I: Generation of the grinding wheel surface 总被引:5,自引:0,他引:5
This paper is in three parts describing the analysis and simulation of the grinding process. This first part is concerned with the generation of the wheel surface by single point diamond dressing. In grinding, the grinding wheel has to be dressed periodically to restore wheel form and cutting efficiency. Understanding the process of generating the grinding wheel surface is important for the control of the grinding process. Generation of the wheel surface is simulated as a single diamond dressing process on a computer generated wheel. The wheel is simulated by grains randomly spaced in the wheel volume. The topography of the wheel cutting surface is generated by simulating the action of an ideal dressing tool as it dresses the wheel. The simulation of the wheel topography takes account of the motion of the dressing tool, grain size, grain spacing, grain fracture and grain break-out. The simulated cutting surface is used for further simulations of grinding. The simulation of grinding using the simulated grinding wheel surface is described in Sections 2 and 3 where a comparison is made of results predicted from simulation with results obtained from experiments. By matching simulated and experimental results, it is possible to explain the relative importance of dressing and grinding parameters. 相似文献
11.
The study of numerical abilities, and how they are acquired, is being used to explore the continuity between ontogenesis and environmental learning. One technique that proves useful in this exploration is the artificial simulation of numerical abilities with neural networks, using different learning paradigms to explore development. A neural network simulation of subitization, sometimes referred to as visual enumeration, and of counting, a recurrent operation, has been developed using the so-called multi-net architecture. Our numerical ability simulations use two or more neural networks combining supervised and unsupervised learning techniques to model subitization and counting. Subitization has been simulated using networks employing unsupervised self-organizing learning, the results of which agree with infant subitization experiments and are comparable with supervised neural network simulations of subitization reported in the literature. Counting has been simulated using a multi-net system of supervised static and recurrent backpropagation networks that learn their individual tasks within an unsupervised, competitive framework. The developmental profile of the counting simulation shows similarities to that of children learning to count and demonstrates how neural networks can learn how to be combined together in a process modelling development. 相似文献
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Integrative process chain optimization using a Genetic Algorithm 总被引:1,自引:1,他引:0
For the production of forged components, it is necessary to coordinate and optimize the production stages along the process
chain. This includes the mainstream processes as well as the associated process chain of the die manufacturing. Up to now,
these processes and process chains are planned and optimized independent from each other because of the different and often
contradictory target criteria. In this paper, a new approach for a holistic optimization of forged process chains will be
presented. At first, a systematic mathematical dependency-analysis between the processes of an application scenario was carried
out. Based on this analysis, a holistic Pareto-based optimization of the process parameters by the use of a Genetic Algorithm
was consecutively performed. The article ends with the presentation and discussion of the computational results. 相似文献
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This paper introduces new algorithms for analysis and optimization of infeed centerless grinding, based on high-level integration of grinding models into a web-based simulation. This holistic approach to simulation facilitates system-level simulation and solvers for several interlinked problems associated with the process mechanics. Emphasis is on structuring the model-based simulation as well as adapting and incorporating the underlying models into the algorithms. Geometric lobing-, chatter- and spinning-related process stability, as well as a time domain continuity equation, are integrated into the simulation to analyze the main quality-related limitations of the process. Once the process stability is assured for the process set-up, optimization strategies and a new infeed cycle definition function are proposed to achieve a minimal or target cycle time. An example of experimental optimization is provided to compare a high-quality process with a target cycle time to an optimized high-productivity process – demonstrating a 70% reduction in cycle time. 相似文献
16.
带钢热连轧过程轧制力三维有限元模拟 总被引:1,自引:0,他引:1
在现代计算机控制的带钢生产中,轧制力的设定极其重要.根据宝钢轧制力模型和现场实测数据,结合热连轧过程中带钢三维变形和热力耦合的特点,应用DEFORM-3D软件建立了带钢热连轧前两个道次的有限元模型,模拟了热连轧过程中两个道次的轧制力变化,并与宝钢模型计算值和实测值进行了对比.结果表明,有限元法计算的轧制力与现场实测数据接近,两者误差在5.0%以内,同时有限元法的计算精度高于宝钢轧制力模型,特别是在第一道次,轧制力计算精度高出4.0%,该模拟为现场轧制工艺参数的调整优化提供了重要的参考价值. 相似文献
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The optimization of technology chains is usually conducted as a local problem of each individual process step. However, in order to optimize the technology chain in terms of product properties a local optimization is insufficient and a more holistic approach is indispensable. Existing methods, which consider the manufacturing history of a workpiece, are often accompanied by a high level of effort in research. This paper presents a systematic approach to integrate the manufacturing history into the technology chain optimization process going along with a significant reduction of effort compared to existing methods based on simulation and experiments. Resulting from previous methods and models a set of representative variables is identified to describe interactions and dependencies within technology chains. Furthermore, an approach consisting of three steps is developed which allows a visualization as well as an explanation of the cause-and-effect relationships within technology chains. This approach is used to deduce two different optimization strategies for technology chains. The first strategy allows a global optimization by adjusting specified parameters without changing the processes within the technology chain. Whereas the second strategy comprises a redesign of the whole chain. 相似文献
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有限元模拟成形仿真的结果,可以帮助设计开发者正确选择冲压工艺参数和模具形状及材料特性等。在对模拟进行后处理过程中,往往必须了解由有限元节点构成的参数曲面的性质,为后续回弹分析及毛坯设计提供重要支持。如何应用变形后的节点阵构成光顺的几何曲面是问题的关键。文章给出了由节点序列散点构成非均匀B样条光顺曲面的实际算法,并开发了应用程序。对散乱点数据构成曲面进行了系统的阐述,所开发的方法已经用于板料成形仿真中FE网格节点重构曲面。 相似文献
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1Introduction Forming multi-level component in die compaction,the density is more or less inhomogeneous depending onthe part geometry,the tool design and the frictionbetween powder and die wall[1?3].The productdistortions are result of inhomogeneous densi… 相似文献
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环件轧制过程三维动态数值模拟 总被引:1,自引:0,他引:1
由于环件轧制受到静力学、运动学和动力学因素的影响,使得控制环件成形具有高度的复杂性,采用传统的试凑法很难满足产品研发的需要。本文基于通用动力显式有限元软Ansys/LS dyna建立了RAW200/160-5型径轴向轧环机的三维仿真模型,对某矩形截面环件进行了虚拟轧制,结果显示了环件扩展和缺陷生成的动态过程以及应力、应变和位移云图。仿真结果表明,采用计算机模拟环件轧制生产过程,对于优化毛坯形状,制定或修改环件轧制工艺,缩减产品研发时间,降低生产成本,提高轧制效率具有重要的意义。 相似文献