基于响应面法的异型腔模具顺序注塑成型工艺参数优化

提出了基于响应面法(RSM)和有限元分析技术的顺序注塑成型(SIM)工艺参数优化方法,解决时序阀浇口设置对异型腔模具充填平衡性的影响。以阀浇口延时开启时间为设计变量,采用中心复合设计(CCD)进行试验规划,运用Moldflow有限元软件进行充填平衡性分析,并引入熵值权重法和线性加权和法对充填结束时间差和综合成型质量评价指标进行数值处理,基于有限元分析结果和响应面法构建了充填平衡性预测模型,应用构建的模型确定了最优工艺参数组合,并进行了数值模拟和生产试验验证。近似模型获得的目标预测值与模拟验证值相对误差为4.2%,优化后异型腔模具充填平衡性提高了23%,表明了所提出方法的有效性。     

基于灰色关联分析和响应面法的复合材料缠绕成型多目标工艺参数优化

针对复合材料预浸带缠绕过程中制品的残余应力、孔隙率最小化和层间剪切强度（ILSS）最大化的多目标优化问题,采用Box-Behnken Design （BBD）原理设计四因素三水平的T300/环氧树脂预浸带缠绕实验;基于灰色关联分析（GRA）将多目标优化问题转化为单目标优化问题,利用主成分分析（PCA）法确定残余应力、孔隙率和ILSS对灰色关联度（GRG）的影响权重;通过对实验数据的回归分析,建立GRG与主要缠绕工艺参数（缠绕温度、张力、压辊压力和缠绕速度）的二阶预测模型;分析了各工艺参数对残余应力、孔隙率、ILSS和GRG的影响规律,确定缠绕工艺参数优化方案;利用响应面法（RSM）求解工艺参数优化问题并进行复合材料预浸带缠绕实验。结果表明:该优化方法获得的最优工艺参数组合可以有效改善残余应力、孔隙率和ILSS,提高预浸带缠绕制品的性能。      

热塑性预浸带缠绕工艺参数及加热方式对成型质量及内应力的影响

采用热塑性预浸料带APC-2/AS4 进行了热芯和火焰两种方法的缠绕研究, 分析了两种方法成型时预浸料带的温度2时间过程和两种方法下工艺参数对成型质量及内应力的影响。结果显示: 热芯缠绕时制件的厚度受芯模温度限制, 而火焰缠绕则不受限制。热芯缠绕时, 缠绕张力和预浸料带的树脂含量是影响制件质量的主要因素。      

复合材料层板热压工艺参数的分析与优化

在热固性树脂基复合材料热压成型过程中,外加压力和加压时机是决定层板厚度、纤维含量以及孔隙含量的两个主要因素.基于复合材料热压成型过程树脂流动模型,采用遗传算法,根据固化层板纤维体积分数的要求,对单向和正交两种铺层形式的T700/5228和T700/5224层板加压时机进行了分析.以航空航天应用的典型纤维含量为准,对优化得到的加压时机以及不同工艺条件下固化层板内纤维分布特点进行了分析.结果表明,纤维、树脂种类相同,铺层方式不同,加压时机差别很大;纤维种类、铺层方式以及初始和优化目标相同的条件下,不同树脂体系,加压时刻树脂粘度基本相同;层板内纤维分布均匀性主要由纤维层压缩特性决定.采用本文建立优化方法,可以快速地得到满足目标纤维含量要求的加压时机,具有重要的学术价值和工程应用意义,有助于降低成本,缩短复合材料研制周期.     

注塑成型工艺参数自动设置与优化技术

工艺参数是注塑制品质量的决定性因素之一,其设置与优化一直强烈依赖于工艺人员的经验与水平。工艺参数的自动设置与优化方法研究具有重要的意义,但需要克服工艺参数数量多,与制品、模具、材料耦合强,难以精确建模的难题。近年来,越来越多的研究,尝试采用计算机仿真技术在模拟计算方面的优势,以及智能技术在处理强经验、弱理论领域的优势,来解决该难题。按所采用技术方法的不同,可以分为基于仿真计算的优化、专家系统或实例推理以及实验设计与优化。对上述3类注塑工艺参数的自动设置与优化技术的研究现状进行了综述,介绍了3类注塑成型工艺的特点和局限性,并对今后的研究方向给出了建议。     

医用泡罩包装容器热成型仿真及工艺参数优化

目的通过数值模拟技术,仿真某医用泡罩包装热成型容器在柱塞辅助热成型工艺过程中,不同时刻片材的厚度变化规律及分布情况,并验证有限元仿真模拟结果的可靠性。仿真拉伸头不同预拉伸深度下的热成型容器的壁厚分布情况,找出使壁厚分布更加均匀的最佳预拉伸深度值,以优化工艺参数。方法利用Solid Works软件建立了有限元模型,通过Ansys Polyflow软件仿真该医用泡罩包装容器的热成型工艺过程。并通过对实际热成型产品进行热成型实验,验证了有限元仿真模拟结果的可靠性。结果仿真值与实验值的相对误差约为2%,仿真结果与实际情况大体一致,仿真结果比较可靠。结论通过有限元仿真模拟得到该医用泡罩包装制品的最佳热成型预拉伸深度值为6.5 mm。     

大尺寸纤维复合材料箱体零拔模斜度缠绕成型模具设计

以某型发射箱复合材料箱体为应用对象,探讨了一种零拔模斜度组合式缠绕成型模具的设计,用于大尺寸薄壁结构矩形截面复合材料箱体构件的缠绕成型,以满足长度方向近零拔模斜度的要求。     

RHLCII仿生人工骨新型材料成型工艺的优化

目的:借助于MINITAB统计学软件,采用Plackett-Burman设计和响应面优化法对重组类人胶原蛋白II(RHLCII)仿生人工骨材料成型工艺进行优化研究。方法:首先利用Plackett-Burman设计筛选出对材料抗压强度和孔隙率影响显著的三个因素,即纳米羟基磷灰石(nHA)/RHLCⅡ、京尼平浓度和预冷温度。在此基础上用最陡爬坡试验逼近最大响应区域,找到后续试验的中心点。再利用Box-Behnken实验设计及响应面分析法进行回归分析,确定主要影响因素的最佳水平。结果:优化后的三种主要影响成分为nHA/RHLCⅡ=1.54、京尼平浓度0.9%和预冷温度-75℃。结论:方程拟合良好,优化后的材料机械强度和孔隙率分别为81.56MPa、94.5%,较优化前分别提高了1.11MPa和0.9%;MTT测定结果表明材料细胞毒性试验合格,符合骨组织工程支架材料的要求,重复性好,有望应用于商品化生产。     

注塑成型工艺参数对制品体收缩率变化的影响及工艺参数优化

结合CAE及Taguchi DOE技术研究工艺参数对注塑制品体收缩率变化(制品中体收缩率的最大值与最小值的差值)的影响并获得优化的工艺参数以使制品的体收缩率变化最小。文中采用L9(3^4)正交矩阵进行实验,并研究了各个参数对制品体收缩率变化的影响程度,对于所选参数,保压压力和模具温度对注塑制品的体收缩率变化的影响较大。     

基于复合优化方法立式数控加工中心的多目标优化设计

为实现加工中心动静态性能不低于优化前性能,达到整机重量最轻的要求,本文提出了一种复合优化方法来研究多变量、多约束和多目标的数控加工中心优化设计。采用有限元分析和实验模态测试方法分析各大件动态性能,并验证了有限元模型的精确性。然后以该有限元模型为基础进行静态分析,得出各大件的最大变形及应力等。以柔度为目标,采用变密度法拓扑优化设计立柱结构的外形框架;以固有频率为目标,基于元结构的可适应性动态优化方法设计加工中心的筋板结构;以固有频率和质量为目标,基于响应面法的尺寸优化确定各结构的最优尺寸。最后将优化后的各大件进行整机装配,分析校核整机动静态性能。分析结果表明,优化后的整机在保证加工中心动静态性能的条件下,整机质量从12749kg减少到12127kg,减重达到4.9%,达到了整机的优化设计要求,说明该方法具有较高的精度和较强的工程实用性。     

基于多场耦合方法的厚截面复合材料固化过程的多目标优化

针对厚截面复合材料固化过程温度峰值过大所引起的材料力学性能降低及残余应力过大等问题,建立了基于多场耦合方法的复合材料固化过程多目标优化模型,用以降低固化温度峰值和缩短固化时间.首先建立包含热化学子模型、树脂黏度子模型和流动压实子模型的固化温度多场耦合模型,用以准确描述固化过程复合材料内部温度及构件厚度的演化规律.通过与...     

基于代理模型和改进遗传算法的注塑翘曲优化

提出一种最小化制品翘曲的注塑工艺参数优化集成方法.以空调柜机顶盖注塑制品开发为例,该方法使用Moldflow软件分析制品的翘曲变形,运用田口方法确定与制品翘曲量密切相关的工艺因素,然后采用响应曲面法(RSM)和改进的精英保留自适应遗传算法(EAGA)相结合的方法,建立主要影响工艺参数与制品翘曲量之间的关系模型,通过对模型寻优以实现对制品翘曲的优化.该方法的适用性在制品的实际生产中得到了验证.     

Optimisation of cutting parameters for minimizing carbon emission and maximising cutting quality in turning process

Modern manufacturing systems are faced with the challenge of reducing the carbon emission related to manufacturing technologies. Machining centres consume large amounts of energy and as a consequence; carbon emissions are generated owing to this consumption. This paper presents a design of experiment work related to the optimisation of machining factors in the turning process of aluminium alloys. Carbon emission and surface quality were concurrently optimised. A set of experimental scenarios was set using a Box–Behnken design and the response surface methodology was applied to get the regression model for the carbon emission and surface roughness during turning process. The relationship between factors and the responses (carbon emission and surface quality) was investigated using surface plots. Furthermore, the desirability function method using the Response Optimizer tool in MINITAB and goal programming methodology was used to obtain the values of the parameters that achieved minimum surface roughness and a minimum quantity of carbon emission.     

Response surface approximations for structural optimization

Response surface methodology can be used to construct global and midrange approximations to functions in structural optimization. Since structural optimization requires expensive function evaluations, it is important to construct accurate function approximations so that rapid convergence may be achieved. In this paper techniques to find the region of interest containing the optimal design, and techniques for finding more accurate approximations are reviewed and investigated. Aspects considered are experimental design techniques, the selection of the ‘best’ regression equation, intermediate response functions and the location and size of the region of interest. Standard examples in structural optimization are used to show that the accuracy is largely dependent on the choice of the approximating function with its associated subregion size, while the selection of a larger number of points is not necessarily cost-effective. In a further attempt to improve efficiency, different regression models were investigated. The results indicate that the use of the two methods investigated does not significantly improve the results. Finding an accurate global approximation is challenging, and sufficient accuracy could only be achieved in the example problems by considering a smaller region of the design space. © 1998 John Wiley & Sons, Ltd.     

复合材料非连续带材缠绕控制技术研究

为实现复合材料带缠绕大拉伸比的工艺要求,提出了非连续带材缠绕.在分析成型工艺过程和可能存在技术难点的基础上,对影响缠绕制品质量的张力、布带拉伸比、布带自动续接及自动纠偏等因素的控制方法及相互作用机理进行了研究.根据缠绕工艺要求,设计出机械装置和控制方案.为验证方案的合理性,在非连续带材缠绕机上做了工艺试验,并对缠绕样件的性能指标进行了对比分析.经应用验证,变张力控制使布带缠绕、布带续接过程具有不同张力,保证整个缠绕过程的恒拉伸比,同时不会使布带在搭接处重新断开,实现了非连续带材的自动化缠绕.     

响应面法优化ZnCl2/AlCl3改性生物炭吸附甲基紫工艺

利用高温热解法制备ZnCl₂/AlCl₃改性生物炭,将其用于吸附甲基紫染料。探究ZnCl₂/AlCl₃-AC投加量、溶液pH、甲基紫浓度、反应时间和吸附温度这5个因素对甲基紫吸附率的影响。利用Plackett-Burman设计联合响应面分析法,筛选优化出对甲基紫吸附率影响较为显著的因素,并探究各因素间的交互影响作用,确定ZnCl₂/AlCl₃-AC吸附甲基紫的最佳工艺条件。结果表明:在选取的五个因素中,对甲基紫吸附率影响显著的因素为ZnCl₂/AlCl₃-AC投加量>甲基紫浓度>吸附温度;其中ZnCl₂/AlCl₃-AC投加量和吸附温度对甲基紫吸附率影响最明显,甲基紫浓度和吸附温度影响最不显著;ZnCl₂/AlCl₃-AC吸附甲基紫最佳工艺条件为:活性炭投加量为47.00 mg、甲基紫溶液浓度为82.00 mg/L、吸附温度为22.90℃,pH为7、反应时间为120 min,其甲基紫吸附率可达到93.04%,与模型预测值的误差仅为3.51%。     

Influence of filament winding parameters on composite vessel quality and strength

An experimental design investigation of manufacturing and design variables that affect composite vessel quality, strength, and stiffness was conducted. Eight 20-in. cylinders (with one additional cylinder as a replicate) were manufactured and tested for hoop strength, hoop stiffness, fiber and void volume fraction distribution through thickness, residual stress, and interlaminar shear strength. Material and processing variables were divided into five categories: (a) resin, (b) fiber, (c) fabrication process, (d) design, and (e) equipment. Five variables were selected (from a list of 12) for study using a 1/4 fractional factorial design of experiment setup. The five variables were: (a) winding tension, (b) stacking sequence, (c) winding-tension gradient, (d) winding time, and (e) cut-versus-uncut helicals.

Statistical analysis of the data shows that the composite vessel strength was affected by the manufacturing and design variables. In general, it was found that composite strength was significantly affected by the laminate stacking sequence, winding tension, winding-tension gradient, winding time, and the interaction between winding-tension gradient and winding time. The mechanism that increased composite strength was related to the strong correlation between fiber volume in the composite and vessel strength. Cylinders with high fiber volume in the hoop layers tended to deliver high fiber strength.     

Optimization of process parameters for transalkylation of toluene to xylene using response surface methodology

ABSTRACT

H-beta zeolite was modified by the ion exchange method to replace its H⁺ ions with Ce⁴⁺ ions. The catalytic performance of this cerium exchanged beta zeolite was evaluated for vapor phase transalkylation of 1,2,4 TMB (1,2,4 trimethylbenzene) with toluene for the production of xylene in a fixed bed, down-flow reactor. The modified zeolite was found to be highly active for this transalkylation reaction. The response surface methodology (RSM) is used for designing the experiments. The effect of three important reaction parameters viz. temperature, reactant ratio, and space time on response variables (toluene conversion and xylene selectivity) is studied and discussed. All the three selected reaction parameters were found to be significant for the toluene conversion; whereas, xylene selectivity was not much influenced by the temperature. The optimum values of the reaction parameters predicted by the model (temperature: 409.7°C, reactant ratio: 2.024, and space time: 4.451) were validated by an experimental run. The results of the experimental run were in close agreement with the model predicted results.