Investigation of ductile iron casting process parameters using Taguchi approach and response surface methodology

To find the optimized levels of various casting parameters in the ductile iron casting, various casting defects and the rejection rate were observed from a medium scale foundry. The controlled values of different casting parameters such as pouring temperature, inoculation, carbon equivalent, moisture content, green compression strength, permeability and mould hardness were selected. Three different melts of metal with 0.4wt.%, 0.6wt.%, and 0.8wt.% inoculation(Fe-Si-Mg alloy and post inoculant) were produced using a 1-ton capacity coreless medium frequency induction furnace. L-27 orthogonal array with 3-level settings were chosen for the analysis. Responses for each run were observed. The signal-to-noise(S/N) ratio for each run was calculated using the Taguchi approach, and the optimized levels of different casting parameters were identified based on the S/N ratio. The analysis of variance for the casting acceptance percentage concludes that inoculation is the most significant factor affecting the castings' quality with a contribution percentage of 44%; an increase in inoculation results in a significant improvement in acceptance percentage of ductile iron castings. The experiment results showed that with the optimized parameters, the rejection rate was reduced from 16.98% to 6.07%.

Optimization of safflower oil transesterification using the Taguchi approach

Biodiesel is an alternative renewable fuel which is produced by using biomass resources. Its physicochemical properties are close to those of the petroleum diesel fuel. This study highlights biodiesel production from safflower seed oil. The main aim of this experimental work is to optimize the process parameters, namely the methanolto-oil molar ratio, catalyst concentration, reaction time and reaction temperature for biodiesel production. The Taguchi robust design approach was used with an L9 orthogonal array to analyze the influence of process factors on performance parameters. The results showed that the optimum yield of biodiesel was 93.8% with viscosity 5.60 c St, with a methanol-to-oil molar ratio of 4:1, catalyst concentration of 1.5 wt%, reaction time of 90 min and reaction temperature of 60 ℃. The catalyst concentration was found to be the most influencing parameter which contributed 51.1% and 50.8% of the total effect on the yield of biodiesel, Y;, and viscosity of biodiesel, Y;, respectively.

Specific energy optimization in sawing of rocks using Taguchi approach

This work aims at selecting optimal operating variables to obtain the minimum specific energy(SE) in sawing of rocks.A particular granite was sampled and sawn by a fully automated circular diamond sawblades.The peripheral speed,the traverse speed,the cut depth and the flow rate of cooling fluid were selected as the operating variables.Taguchi approach was adopted as a statistical design of experimental technique for optimization studies.The results were evaluated based on the analysis of variance and signal-to-noise ratio(S/N ratio).Statistically significant operating variables and their percentage contribution to the process were also determined.Additionally,a statistical model was developed to demonstrate the relationship between SE and operating variables using regression analysis and the model was then verified.It was found that the optimal combination of operating variables for minimum SE is the peripheral speed of 25 m/s,the traverse speed of 70 cm/min,the cut depth of 2 cm and the flow rate of cooling fluid of 100 mL/s.The cut depth and traverse speed were statistically determined as the significant operating variables affecting the SE,respectively.Furthermore,the regression model results reveal that the predictive model has a high applicability for practical applications.

Investigation of Heat Transfer Augmentation between the Ribbed Plates via Taguchi Approach and Computational Fluid Dynamics

Heat transfer and turbulent flow characteristics between the ribbed plates have been numerically studied in the present paper.The ribs with the rectangular cross-section have been placed on the top and the bottom plates of the duct,symmetrically.It is assumed that the fluid at 300 K has entered the system while the walls kept at 400 K.All numerical analyses have been performed by k-ωShear Stress Transport(SST)turbulence model for Re=10000,15000 and 20000.For the fixed rib width,the dimensionless height and the dimensionless spacing have been respectively varied as 0.1≤h’≤0.3 and 0.5≤S’≤1,and the results have been compared with the ones of the smooth plate.Even though there are twenty-seven cases obtained as a result of parametric combinations,the number of various cases has been reduced from twenty-seven to only nine different variations by applying the Taguchi method.Furthermore,the effects of all the considered parameters on the heat transfer and flow characteristics have been determined in terms of the influence degree.The optimum parameters for Nusselt number and pressure loss have been ascertained individually.What is more,the almost exact values for Nusselt number and pressure loss have also been attained by the confirmation test having an error percentage of 6%.The most dominant factor has been determined as the rib height due to its effect on both heat transfer and flow characteristics.Similarly,with respect to the numerical results,increasing the rib height,the rib spacing and Reynolds number has separately increased Nusselt number.Nevertheless,symmetrical flow structure has been disturbed as a result of ascending the rib height as clearly seen for h’=0.3 from the charts.In the meantime,pressure loss has been augmented owing to the increment of the geometrical parameters and also Reynolds number.h’=0.1 with S’=0.5 at Re=10000,h’=0.2 with S’=0.5 at Re=15000 and h’=0.1 with S’=0.75 at Re=15000 can be suggested for the heat transfer enhancement since the pressure loss of the system is tolerated.

Optimization by the Taguchi Method of a Robust Synthesis Protocol of Calcium Carbonate Phosphate

The experimental processes are difficult to model by physical laws, because a multitude of factors can intervene simultaneously and are responsible for their instabilities and their random variations. Two types of factors are to be considered;those that are easy to manipulate according to the objectives, and those that can vary randomly (uncontrollable factors). These could eventually divert the system from the desired target. It is, therefore, important to implement a system that is insensitive to fluctuations in factors that are difficult to control. The aim of this study is to optimize the synthesis of an apatitic calcium carbonate phosphate characterized with a Ca/P ratio equal to 1.61 by using the experimental design method based on the Taguchi method. In this process, five factors are considered and must be configured to achieve the previously defined objective. The temperature is a very important factor in the process, but difficult to control experimentally, so considered to be a problem factor (noise factor), forcing us to build a robust system that is insensitive to the last one. Therefore, a much simpler model to study the robustness of a synthetic solution with respect to temperature is developed. We have tried to parameterize all the factors considered in the process within a wide interval of temperature variation (60˚C - 90˚C). Temperature changes are no longer considered as a problem for apatitic calcium carbonate phosphate synthesis. In this finding, the proposed mathematical model is linear and efficient with very satisfactory statistical indicators. In addition, several simple solutions for the synthesis of carbonate phosphate are proposed with a Ca/P ratio equal to 1.61.

Optimization of PVD process parameter for coating AZ91D magnesium alloy by Taguchi grey approach

This study was an attempt made to explore the possibility of increasing the surface properties of the AZ91D magnesium alloy by applying ZrO_(2)coating using Physical Vapour Deposition(PVD-RF)sputtering process.In order to improve the quality of the coating,the PVD process parameter with multiple performance characteristics was optimized by using the Taguchi grey approach.L 18 orthogonal array was selected for conducting the experiments.The proposed Taguchi grey method was find out the optimal process parameter for multiple performance characteristics.The optimal combination was attained at chamber pressure of 0.003 bar,argon gas in millibar and power input of 200 W.The validation experiment result shows an improvement in the micro hardness and surface finish.Also,the performance characterizations such as SEM,EDX,XRD,coating thickness,surface roughness and micro hardness were measured at optimal process parameter.

Utilization of Industrial Waste Slag as Aggregate in Concrete Applications by Adopting Taguchi’s Approach for Optimization

This paper presents result of an experimental investigation carried out to evaluate effects of replacing aggregates (coarse & fine) with that of Slag (Crystallized & Granular) which is an industrial waste by-product on concrete strength properties by using Taguchi’s approach of optimization. Whole study was done in three phases, in the first phase natural coarse aggregate was replaced by crystallized slag coarse aggregate keeping fine aggregate (natural sand) common in all the mixes, in the second phase fine aggregate (natural sand) was replaced by granular slag keeping natural coarse aggregate common in all the mixes and in the third phase both the aggregates were replaced by crystallized & granular aggregates. The study concluded that compressive strength of concrete improved almost all the % replacements of normal crushed coarse aggregate with crystallized slag by 5% to 7%. In case of replacements of fine aggregate and both type of aggregates, the strength improvements were notably noticed at 30% to 50% replacement level. It could also be said that full substitution of slag aggregate with normal crushed coarse aggregate improved the flexure and split tensile strength by 6% to 8% at all replacements and in case of replacing fine aggregate & both the aggregates( Fine & coarse) with slag, the strength improvement was at 30% to 50% replacements. It is evident from the investigation that Taguchi approach for optimization helped in indentifying the factors affecting the final outcomes. Based on the overall observations, it could be recommended that Slag could be effectively utilized as coarse & fine aggregates in all concrete applications.

Taguchi设计方法和有限元分析方法在车门系统设计中的应用

为了缩短设计周期、降低计算成本、提高产品竞争力,笔者提出将Taghchi设计和有限元分析相结合的方法应用于车门系统的设计。根据正交矩阵的试验方案,对详细设计阶段的车门系统进行静态有限元分析,识别出影响车门下沉量和应力最敏感的因素,选出最优方案。试验结果表明,通过该种方法获得的设计方案,在较大程度上提高了车门品质,在达到产品性能要求的同时,使得设计的目的性更强,并缩短了设计的周期。

基于田口可靠性试验的截尾数据处理方法

【目的】当田口方法用于产品可靠性改进时,作为响应变量的寿命的观测数据通常是截尾的。对于截尾数据,田口数据分析方法不再适用,需寻求新的数据处理方法解此问题。【方法】提出威布尔分位函数近似法估计右截尾时间的中位剩余寿命,并用截尾时间和中位剩余寿命之和代替右截尾寿命,从而将不完全数据变换为完全数据,进而完成田口数据分析。【结果】通过两个仿真数例,说明了采用所提出方法得到的中位剩余寿命估计是相对精确的、稳健的;通过一个实例,说明了该方法的有用性。【结论】本文为可靠性改进试验数据分析提供了一个简单有效的数据处理方法。

TA15钛合金激光-电弧复合热源焊接工艺优化

利用Nd:YAG脉冲激光-TIG复合热源对厚2.5 mm TA15钛合金进行对接焊工艺试验。为了对焊接接头力学性能进行控制,本文以焊缝的最大抗拉强度作为评价焊接质量的品质特性,对影响焊接质量的四项工艺参数(激光功率、电弧功率、DLA、焊接速度)利用田口法进行优化设计。通过信噪比分析,获得最优参数水平组合,同时进行方差分析,结果表明:激光功率和焊接速度对焊接质量的影响最为显著,优化后工艺参数对试板进行焊接,发现增加了22%激光功率的复合热源焊接熔化能量是电弧焊的2.4倍,获得的焊缝成形质量连续、美观,且静拉伸断口位于母材处,说明接头力学性能可靠。

多因素对上肢典型操作疲劳评估的影响(英文)

目的研究8个重要因素在上肢典型操作时对疲劳评估的影响。方法将32名被试者分为男性青年组(G1)、男性中年组(G2)和女性组(G3)。通过L16(44×23)正交表把6个因素的不同水平组合进行排列,被试者按照此表中的变量组合设置进行每人16次的上肢曲/伸操作。实验过程中记录主观疲劳得分(BFI)主观疲劳得分并计算对应时刻的对外输出功,两者相结合来评估操作策略。结果G1和G2组差异(年龄)不显著,而G1+G2和G3组的差异(性别)达到39%(P<0.05)。手臂舒展程度、操作频率、操作方向、负荷、姿势对工作性能的影响是不一样的。对于这3个组的各个因素优选条件是完全一致的。结论操作绩效中的性别差异比国外同类研究的数值大,要引起更多的关注。不同因素的特定组合可以提高操作绩效。

基于有序微造型的圆弧线槽干气密封性能分析

基于激光技术的干气密封开槽方法,提出在圆弧线槽干气密封(A-DGS)槽底开设粗糙度量级的有序微造型,以提高开槽效率、降低成本。采用有限体积法对无微造型圆弧线槽干气密封进行仿真分析,通过与现有文献对比验证了仿真方法的正确性;对微造型结构进行分析和筛选,获得偏移迎风侧与偏移背风侧结构对密封性能影响基本无差,本研究基于偏移背风侧微造型结构进行深入研究;与无微造型圆弧线槽进行对比,分析了不同几何参数和工况参数下的开启力和泄漏量变化情况;最后对各参数的影响程度进行对比分析。结果表明:同工况下,具微造型圆弧线槽干气密封(MA-DGS)的开启力较A-DGS有一定提升,在低速高压及小槽深时提升效果最好;微造型深度和微造型宽间比对干气密封开启力的影响在给定情况下甚于膜厚与转速的影响;密封端面槽型结构优化参数不受槽底微造型设计的影响;基于Taguchi实验设计方法,可以便捷准确地获得不同影响因子的影响程度,帮助工程设计。

基于满意度函数的多响应稳健优化设计研究综述

在21世纪的竞争环境中,满足顾客多样化需求是企业面临的一大挑战。基于此,本文阐述了在产品设计过程中如何同时优化多个质量特性,并使得最终参数符合稳健设计的理念。本文在回顾了响应曲面法、田口三次设计法、满意度函数法的基础上,综合分析了目前多响应稳健优化设计的研究现状,最终提出将信噪比作为衡量多响应稳健性指标的可行性。

搅拌摩擦技术制备AA6061/SiC纳米复合材料的工艺参数优化(英文)

采用搅拌摩擦技术制备AA6061/SiC纳米复合材料,并用实验设计方法来确定影响AA6061/SiC复合材料极限拉伸强度的重要因素,包括4种因素,即旋转速度、横向速度、切削深度、搅拌头形状。运用Taguchi方法,得到优化的工艺参数。方差分析表明,旋转速度是最主要的影响因素。统计分析结果表明,采用带螺纹的搅拌头得到的复合材料的极限拉伸强度比采用方型搅拌头的高。搅拌头的旋转速度越快、横向速度越慢,则复合材料的极限拉伸强度越高。