共查询到17条相似文献,搜索用时 265 毫秒
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并行遗传算法在模具型腔形状优化设计中的应用 总被引:2,自引:1,他引:2
针时挤压模具型腔形状的优化设计,提出了并行微观遗传优化方法,该方法采用多种群的并行微观遗传算法进行优化计算,利用BP神经网络的预测功能获得目标函数值,采用三次样条插值函数表达挤压模具型腔形状。训练BP神经网络模型的导师信号利用刚塑性有限元数值计算获得。以表面栽荷沿凹模型腔轮廓表面均匀分布为目标,建立了优化数学模型,对挤压模具型腔轮廓形状进行了优化设计。采用有限元软件MARC/AutoForge对优化结果进行了有限元仿真,仿真结果验证了优化结果的有效性。 相似文献
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挤压模具型腔的等磨损优化设计 总被引:1,自引:0,他引:1
针对目前国内挤压模具寿命过低的情况,将有限元分析、神经网络和遗传算法结合起来应用到挤压模具型腔优化设计中。采用B样条函数插值描述凹模型腔轮廓形状,用有限元数值模拟获得型腔表面节点的应力场、速度场和温度场,基于修正Archard磨损模型计算型腔磨损深度,以此作为样本训练BP神经网络,建立模具型腔控制点与磨损深度之间的映射关系,再结合遗传算法以等磨损为目标,优化模具型腔轮廓形状。优化结果与序列二次规划法一致,可以降低模具磨损,提高模具寿命,结果与实际情况吻合,表明了这种设计方法是可行的。 相似文献
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针对管道布局、最大允许能耗给定条件下快速热循环注塑成形(RHCM)注塑模具型腔表面快速均匀加热的问题,提出以单根加热棒热流密度为设计变量,以模具型腔表面升温效率和温度分布均匀性为目标,结合有限元模拟、响应面设计以及多目标粒子群优化技术来优化RHCM模具电加热系统。与优化前相比,加热系统优化后,模具型腔表面最大温差降低63.4%,加热系统总能耗降低9%。对比了不同注塑成形工艺条件下成形的平板塑件表面质量,结果表明,相对传统注塑成形(CIM)工艺,RHCM工艺将制品表面粗糙度Ra从320 nm降低到118 nm,并有效抑制了制品表面熔接痕、缩痕等缺陷;发现制品表面粗糙度与型腔表面对应点温度成负相关,说明优化后的型腔表面温度分布更有利于提升制品表面质量。 相似文献
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一套模具中有多个型腔,这种模具称为一模多腔模具。对于小尺寸塑件大多采用该类型模具。一模多腔模具有两种形式:一种是各个型腔尺寸相同并按规律排列,另一种是型腔尺寸或形状不同,组合在一套模具中。本文以端盖塑件为例利用Pro/E中模具设计分型面法来阐述型腔尺寸相同的一模多腔模具设计过程。 相似文献
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提出了锥形螺母一次冷镦挤复合成形新工艺,设计了采用管坯冷镦挤成形锥形螺母的模具结构,运用Deform-3D有限元软件,模拟分析了锥形螺母冷镦挤成形过程中坯料填充凹模型腔的流动速度场和等效应力场。结果表明:管坯各处的流动应力值均不超过其材料的流动应力极限,金属坯料可以流动到型腔的各个部位,此工艺能够获得形状完整的锥形螺母。 相似文献
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Guoqun Zhao Hao Chen Cunsheng Zhang Yanjin Guan 《The International Journal of Advanced Manufacturing Technology》2013,69(5-8):1547-1556
The extrusion die plays a crucial role in aluminum alloy profile production, which influences product quality and service life of extrusion die directly. In this paper, a profile with irregular shape was taken as an analysis example, and multiobjective optimization for porthole extrusion die based on modern intelligence algorithm was carried out. Aiming at achieving the uniform velocity distribution in the cross-section of the profile as well as decreasing the maximum stress on the extrusion die and the deflection of the mandrel, the angle between port bridges, the position of die orifice, and the height of welding chamber were considered as the design variables. Then Kriging model was established on the basis of Latin hypercube samplings, and above design variables were optimized using Pareto-based genetic algorithm. Finally, an optimal die structure is gained. Compared with the initial scheme, the velocity distribution in the extrudate was more even, and the stress on the die and the deflection of the mandrel were decreased obviously in the optimal scheme. The optimal design method for porthole die has strong commonality, thus, it could give useful guidelines for practical production of the same kind of aluminum profile. 相似文献
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Designing the optimal shape for an extrusion die to produce a high-quality extrusion product is often required by industry.
Design from experience is unsatisfactory for achieving the flexibility and precision requirements in die design. In this paper,
a design method has been developed for the optimum shape design of extrusion die. The extrusion process was modelled and analysed
by using the finite-element method to obtain the extrusion force and effective strain for different die shapes. A polynomial
network was applied to identify the force and strain models in terms of the geometric parameters of the extrusion die. An
improved genetic algorithm was used to optimise the identified model for optimal shape with minimum force and strain. It has
been verified that the modelling error is extremely small. The designer can quickly and accurately access the optimal shape
of an extrusion die through this new approach.
RID="
ID=" <E5>Correspondence and offprint requests to</E5>: Dr Y.-C. Hsu, Department of Mechanical Manufacturing Engineering,
National Huwei Institute of Technology, 64 Wun-Hua Road, Huwei, Yunlin, Taiwan. E-mail: jasonych@sunws.nhit.edt.tw 相似文献
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基于多目标优化的扁挤压筒结构设计 总被引:4,自引:1,他引:4
在组合式扁挤压筒的结构尺寸设计中,为确保挤压筒最佳工作性能的同时,最大程度地减少过盈装配后内腔产生的变形,提出了多目标优化的概念。结合有限元模拟技术和BP神经网络方法,建立了变过盈量下三层组合式扁挤压筒结构尺寸与各层等效应力分布、内腔位移之间的非线性映射模型,采用多目标遗传算法对其进行优化。优化时,采用了向量评价法、最佳个体保存策略和小生境技术,得到了均匀分布的Pareto最优解,根据定义的满意度函数,选出了最终的满意解。结果表明,在该满意解下,扁挤压筒既实现了等强度设计,又保证了内腔的尺寸精度。 相似文献
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An optimization strategy for die design in the low-density polyethylene annular extrusion process based on FES/BPNN/NSGA-II 总被引:1,自引:1,他引:0
Yue Mu Guoqun Zhao Xianghong Wu Chengrui Zhang 《The International Journal of Advanced Manufacturing Technology》2010,50(5-8):517-532
An optimization strategy for die design in the polymer extrusion process is proposed in the study based on the finite element simulation, the back-propagation neural network, and the non-dominated sorting genetic algorithm II (NSGA-II). The three-dimensional simulation of polymer melts flow in the extrusion process is conducted using the penalty finite element method. The model for predicting the flow patterns in the extrusion process is established with the artificial neural network based on the simulated results. The non-dominated sorting genetic algorithm II is performed for the search of globally optimal design variables with its objective functions evaluated by the established neural network model. The proposed optimization strategy is successfully applied to the die design in low-density polyethylene (LDPE) annular extrusion process. A constrained multi-objective optimization model is established according to the characteristics of annular extrusion process. The minimum of velocity relative difference, δu, and the minimum of swell ratio, S w, that, respectively, ensure the extrinsic feature, mechanical property, and dimensional precision of the final products are taken as optimization objectives with a constrained condition on the maximum shear stress. Three important die structure parameters, including the die contraction angle α, the ratio of parallel length to inner radius L/R i, and the ratio of outer to inner radius R o /R i, are taken as design variables. The Phan-Thien–Tanner constitutive model is adopted to describe the viscoelastic rheological characteristics of LDPE whose parameters are fitted by the distributions of material functions detected on the strain-controlled rheometer. The penalty finite element model of polymer melts flowing through out of the extrusion die is derived. A decoupled method is employed to solve the viscoelastic flow problem with the discrete elastic-viscous split-stress algorithm. The simulated results are selected and extracted to constitute the learning samples according to the orthogonal experimental design method. The back propagation algorithm is adopted for the training and the establishment of the predicting model for the optimization objective. A Pareto-optimal set for the constrained multi-objective optimization is obtained using the constrained NSGA-II, and the optimal solution is extracted based on the fuzzy set theory. The optimization for die parameters in the annular extrusion process of low-density polyethylene is performed and the optimization objective is successfully achieved. 相似文献
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Akshaya Kumar Rout Kalipada Maity 《The International Journal of Advanced Manufacturing Technology》2011,54(5-8):495-506
The geometry of die profile plays a major role in reducing the extrusion pressure and ensuring the smooth flow of material. In general, the extrusion process is mostly affected by billet geometry, die geometry, and interface frictional force at the die billet geometry. In the present investigation, an analysis using three-dimensional upper bound method using fifth-order die profile function has been carried out for extrusion of square sections from square billet. The extrusion pressure and optimum die length have been computed by multivariable optimization technique. The present die shape profile is found to be superior to many other profiles. The results obtained will help in design of optimum die profile and investigation of its performance. 相似文献