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121.
基于响应面法(RSM),通过一系列的实验建立了薄壁蜡模壁厚方向的收缩率与压蜡参数之间的数学模型,并对模型的合理性与充分性进行了方差分析,对压蜡过程中工艺参数对尺寸收缩率的影响进行了敏感性分析.为了减小收缩率,基于遗传算法(GA)对工艺参数进行了全局优化. 相似文献
122.
SOLVINGTHEFREEBOUNDARYPROBLEMINCONTINUOUSCASTINGBYUSINGBOUNDARYELEMENTMETHODLiYaoyong(李耀勇);ZhangZhili(张自立)(ReceivedJune,18,19... 相似文献
123.
124.
In the present work, mathematical models of three important casting processes are considered namely squeeze casting, continuous casting and die casting for the parameters optimization of respective processes. A recently developed advanced optimization algorithm named as teaching–learning-based optimization (TLBO) is used for the parameters optimization of these casting processes. Each process is described with a suitable example which involves respective process parameters. The mathematical model related to the squeeze casting is a multi-objective problem whereas the model related to the continuous casting is multi-objective multi-constrained problem and the problem related to the die casting is a single objective problem. The mathematical models which are considered in the present work were previously attempted by genetic algorithm and simulated annealing algorithms. However, attempt is made in the present work to minimize the computational efforts using the TLBO algorithm. Considerable improvements in results are obtained in all the cases and it is believed that a global optimum solution is achieved in the case of die casting process. 相似文献
125.
依据湍动能理论,本文建立了结晶器内钢液的三维湍流模型,开发了计算程序,研究了不同水口状态下异形坯结晶器中钢水的流动特性.利用本模型所得计算结果与实测结果吻合较好,并可对现场生产进行离线分析. 相似文献
126.
We investigate the effect of the bias in an electron-spin filter based on a two-dimensional electron gas modulated by ferromagnetic-Schottky metal stripes. The numerical results show that the electron transmission and the conductance as well as the spin polarization are strongly dependent on the bias applied to the device. 相似文献
127.
基于人工神经网络建立了反向凝固过程中的性质预测模型,实现了对铸带厚度和新相层晶粒度的全面预测;探讨了凝固过程中的主要工艺参数对上述性能的综合影响。为反向凝固性能的综合预测提供了简便的新手段。 相似文献
128.
M. Digruber W. Schneider K. Mörwald S. Haas 《Archive of Applied Mechanics (Ingenieur Archiv)》2000,70(1-3):17-29
Summary The paper is concerned with a one-dimensional analysis of plane open-channel flow with continuous solidification. The process
is of relevance for recent developments in the casting of steel and other metals. The bottom of the channel consists of a
rotating casting roll and a horizontal cooling table, where the solidified material is withdrawn with given velocity. The
study is restricted to the region downstream of the top of the casting roll. Surface tension is neglected.
In the main part of the analysis inviscid fluid flow is considered since the Reynolds number is very large in the applications.
It is found that the steady-state solutions are nonunique in a certain parameter range. In addition to a continuous solution,
there are two solutions including hydraulic jumps, with one hydraulic jump being located on the casting roll, the other one
on the cooling table. Regarding the stability of the non unique solutions, the evolution of disturbances is investigated numerically
as an initial-value problem. It is concluded that the hydraulic jump on the cooling table is unstable, while the other discontinuous
solution as well as the continuous solution are stable for sufficiently small disturbances. Which stable solution is attained
in the steady state, depends on the history of the process.
Friction at the liquid/solid interface is taken into account in the last part of the analysis. A constant friction coefficient
is assumed. It is found that the history of the process determines the steady-state solution if, and only if, the friction
coefficient is sufficiently small. For larger values of the friction coefficient, the steady-state solution is unique and
independent of the history of the transient process. Furthermore, for sufficiently large friction coefficients, stable hydraulic
jumps are found, in contrast to the inviscid case, also on the cooling table.
Received 19 March 1999; accepted for publication 3 May 1999 相似文献
129.
赵海森 《科技情报开发与经济》2011,21(2):218-220
由于门式架具有加工简便、拆装灵活、搬运方便、通用性强等特点,所以应用非常广泛。详细介绍了门式架在现浇箱梁中作为满堂脚手架的应用。 相似文献
130.
The patternless casting manufacturing (PCM) technique, which adopts a new concept of double scanning method, combines the principle of discreteness and deposition with resin-bonded sand technique. This paper is to evaluate the dimensional accuracy of sand mould on PCM. The two important factors-the liquid penetration rule in the space of particles and the shape and dimension of the agglomeration unit body, which influence the process parameters such as scanning speed, layer thickness, liquid flux on dimension accuracy, and surface qualities, were investigated systematically, thus the theoretical basis for these parameters was provided. Experiments on rapid manufacturing of sand mould were carried out, and the results of the free penetration and the constraint penetration well verified the relationship of the two factors and the process parameters. 相似文献