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Optimal design of four stage launch vehicle considering multi objective NSGA II algorithm and mass-energetic concepts 基于多目标NSGA II算法和质量能概念的四级运载火箭优化设计
Q2 Materials Science Pub Date : 2022-01-01 DOI: 10.5267/j.esm.2022.3.003
Hossein Sabaghzadeh, N. M. Khansari
A solid fuel launch vehicle is a rocket with an engine that has been widely used in aerospace missions. Utilizing such launch vehicles depends on the simplicity of the manufacturing, maintenance, operation and development of the control systems. The purpose of optimization in solid fuel launch vehicles design is to find the best possible design for the mission with regard to the available equipment, constraints and infrastructures. Therefore, the main purpose of this research is to optimally design a launch vehicle for customized missions based on successful experiences, as well as technology, manufacturing capabilities and facilities. In this context, NSGA-II Intelligent Optimization Algorithm is considered based on multi-objective optimization principles and Mass-Energetic concepts. The optimal design of the launch vehicle is performed by applying intelligent algorithms and technological opportunities and limitations. The result showed that the present optimization method can design the launch vehicle based on technological limitations.
固体燃料运载火箭是一种带有发动机的火箭,已广泛用于航空航天任务。利用这种运载火箭取决于控制系统的制造、维护、操作和发展的简单性。固体燃料运载火箭设计优化的目的是在现有设备、限制条件和基础设施的情况下,为任务找到可能的最佳设计。因此,本研究的主要目的是基于成功的经验,以及技术、制造能力和设施,对定制任务的运载火箭进行优化设计。在此背景下,基于多目标优化原理和质量-能量概念,考虑NSGA-II智能优化算法。利用智能算法和技术机遇与局限性对运载火箭进行优化设计。结果表明,本文提出的优化方法可以实现基于技术限制的运载火箭设计。
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引用次数: 0
Proposed method of forecasting cumulative effects of variation in manufacturing 提出了一种预测制造业变化累积效应的方法
Q2 Materials Science Pub Date : 2022-01-01 DOI: 10.5267/j.esm.2022.3.001
Q. Risch
Manufacturing, in general, creates a finished good from a set of simpler supplied parts. Supplied parts are installed into higher assemblies, higher assemblies move into even higher assemblies, and eventually this terminates at the finished good. Delays or variation during the manufacturing process ripple all the way to the finished good, possibly from different branches of the build and possibly magnifying any individual effect. There is extensive literature regarding Lean Manufacturing and it provides strategies and business philosophy to deal with variation, however it offers little in the way of quantitative analysis on the effects of that variation upon the whole. Digital Twins and discrete event simulations can and have been used to model the impact of variation in its totality. Various papers on Digital Twins have explored how to model manufacturing, but very little on generalized behavior. (i.e. How schedule slips at the subassemblies impacts the delivery dates / quantities at the finished good level). This paper explores the analytical quantitative effects of input/sales variation through the manufacturing cycle and the resultant effect on the finished good manufacturing schedule/cycle. We demonstrate that even small random variations/interruptions propagate up the build chain, get reduced in magnitude and end up producing predictable reductions in the average build rate of the final product. Additionally, it is shown that the more supplied parts that comprise a finished good the greater the expected reduction in average build rate.
一般来说,制造业是从一组较简单的供应部件生产出成品。供应的部件被安装到更高的组件中,更高的组件移动到更高的组件中,最终在成品中终止。制造过程中的延迟或变化会一直波及成品,可能来自制造的不同分支,并可能放大任何单个影响。关于精益制造有大量的文献,它提供了处理变化的策略和经营哲学,但是它很少提供对变化对整体影响的定量分析。数字孪生和离散事件模拟可以并且已经被用来模拟其总体变化的影响。关于数字孪生的许多论文都探讨了如何为制造业建模,但很少涉及广义行为。(例如,组件的进度延误如何影响成品水平的交付日期/数量)。本文探讨了通过制造周期对投入/销售变化的分析定量影响,以及由此产生的对成品制造进度/周期的影响。我们证明,即使是很小的随机变化/中断也会在构建链中传播,在量级上得到减少,并最终在最终产品的平均构建速率中产生可预测的减少。此外,它表明,组成成品的供应零件越多,平均建造率的预期降低就越大。
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引用次数: 0
Modeling and simulation of friction stir welding process for AA6061-T6 aluminum alloy using finite element method 采用有限元法对AA6061-T6铝合金搅拌摩擦焊接过程进行建模与仿真
Q2 Materials Science Pub Date : 2022-01-01 DOI: 10.5267/j.esm.2022.2.001
Muleta Tiki Lemi, E. M. Gutema, Mahesh Gopal
Friction Stir Welding (FSW) is a process of welding materials that generates heat through friction. Plastic deformation, nonlinear material movement, tool-to-structural evolution friction, and heat production from friction and plastic deformation all have an impact on FSW operation. In this paper, thermo-mechanical characteristics of aluminum alloy AA6061-T6 during the FSW process were simulated based on COMSOL® software using a finite element approach. A conceptual model was created to interpret the thermal and structural analyses. According to the obtained results, the temperature rises on the top and bottom surfaces as the axial force increases but decreases along the line perpendicular to the weld direction. The overall temperature decreases as the forward welding speed rises within the acceptable induced temperature range of the workpiece, while the axial force and rotational speeds stay stable.
搅拌摩擦焊(FSW)是一种通过摩擦产生热量的焊接工艺。塑性变形、非线性材料运动、工具到结构的演化摩擦以及摩擦和塑性变形产生的热量都对FSW工作产生影响。本文基于COMSOL®软件,采用有限元方法模拟了AA6061-T6铝合金在FSW过程中的热力学特性。创建了一个概念模型来解释热分析和结构分析。结果表明,随着轴向力的增大,顶、底表面温度升高,但沿垂直于焊缝方向的方向温度降低。在工件可接受的诱导温度范围内,随着前向焊接速度的升高,整体温度降低,而轴向力和转速保持稳定。
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引用次数: 2
Modes I-II-III stress intensity factors of a semi-elliptical surface crack at a round bar under torsion loading by FEM and DBEM 扭转载荷作用下圆杆半椭圆表面裂纹的I-II-III型应力强度因子有限元和DBEM分析
Q2 Materials Science Pub Date : 2022-01-01 DOI: 10.5267/j.esm.2022.6.001
M. Barrinaya, Muhammad Nayomi Alfiyuranda, M. Ramezani, I. Putra, Singh Ramesh, P. Kadarno, S. Hastuty, J. Purbolaksono
The corner point singularity of surface cracks by finite element method (FEM) has become a numerical concern decades ago. The literature showed that the stress intensity factors (SIFs) at the corner points were often excluded. Further, most SIFs were reported for larger ratios of the crack depth over cylinder diameter. This paper presents the SIFs (Modes I, II and III) of a semi-elliptical surface crack at a solid round bar under torsion. The tetrahedral and hexahedral elements were used in the finite element modelling. The effects of the loading mode and the crack aspect ratio on the corner point singularity were discussed. The tetrahedral meshing was generally observed to be more suitable for modelling relatively small surface cracks, particularly in respect to the corner point singularity. For all loading modes, the SIFs away from the corner points of using the tetrahedral meshing were found to have fairly good agreement with those by dual boundary element method (DBEM).
表面裂纹角点奇异性的有限元分析在几十年前就已成为数值研究的热点。文献表明,角点处的应力强度因子(SIFs)往往被排除在外。此外,大多数SIFs报告的裂纹深度比圆柱直径大。本文给出了实心圆杆处半椭圆表面裂纹在扭转作用下的SIFs (I、II和III型)。采用四面体和六面体单元进行有限元建模。讨论了加载方式和裂纹长径比对角点奇异性的影响。一般观察到四面体网格更适合于模拟相对较小的表面裂纹,特别是在角点奇点方面。在所有加载模式下,采用四面体网格法得到的远离角点的SIFs与采用双边界元法(DBEM)得到的SIFs具有较好的一致性。
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引用次数: 3
A supervised machine-learning method for optimizing the automatic transmission system of wind turbines 风力发电机自动传动系统优化的监督式机器学习方法
Q2 Materials Science Pub Date : 2022-01-01 DOI: 10.5267/j.esm.2021.11.001
Habeeb A. H. R. Aladwani, M. Ariffin, F. Mustapha
Large-scale wind turbines mostly use Continuously Variable Transmission (CVT) as the transmission system, which is highly efficient. However, it comes with high complexity and cost too. In contrast, the small-scale wind turbines that are available in the market offer a one-speed gearing system only where no gear ratios are varied, resulting in low efficiency of harvesting energy and leading to gears failure. In this research, an unsupervised machine-learning algorithm is proposed to address the energy efficiency of the automatic transmission system in vertical axis wind turbines (VAWT), to increase its efficiency in harvesting energy. The aim is to find the best adjustment for VAWT while the automatic transmission system is taken into account. For this purpose, the system is simulated and tested under various gear ratios conditions while a centrifugal clutch is applied to automatic gear shifting. The outcomes indicated that the automatic transmission system could successfully adjust the spinning in line with the wind speed. As a result, the obtained level of harvested voltage and power by VAWT with the automatic transmission system are improved significantly. Consequently, it is concluded that automatic VAWTs, equipped with the machine-learning capability can readjust themselves with the wind speed more efficiently.
大型风力发电机组多采用无级变速(CVT)作为传动系统,具有较高的效率。然而,它的复杂性和成本也很高。相比之下,市场上现有的小型风力涡轮机仅在没有齿轮比变化的情况下提供单速齿轮传动系统,导致能量收集效率低并导致齿轮故障。在这项研究中,提出了一种无监督机器学习算法来解决垂直轴风力涡轮机(VAWT)自动传动系统的能源效率问题,以提高其收集能量的效率。目的是在考虑自动传动系统的情况下,找到VAWT的最佳调整。为此,在采用离心式离合器进行自动换挡的同时,对该系统进行了不同传动比条件下的仿真和测试。结果表明,自动传动系统能够成功地根据风速调节转速。结果表明,采用自动输电系统的VAWT获得的电压和功率水平得到了显著提高。因此,具有机器学习能力的自动vawt可以更有效地根据风速进行自我调整。
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引用次数: 1
Prediction and investigation between impeller blade shape parameters and performance parameters in CFD and ANN CFD和人工神经网络中叶轮叶片形状参数与性能参数的预测研究
Q2 Materials Science Pub Date : 2022-01-01 DOI: 10.5267/j.esm.2021.12.003
F. Jin, R. Tao, R. Xiao
The blade shape parameters have a remarkable effect on the centrifugal pump performance. In order to reveal the relationship between these parameters and pump performance, a single channel was regarded as the research object to calculate its performance by numerical simulation, and the performance was measured on an experimental rig. The optimized ANN is proposed, and it is proved to be highly accurate. The ANN correlation coefficient of the total response could be above 0.997 after thousands of retaining. The sorts and degrees affecting performance parameters were found out by gray relation analysis. It was found that the blade angles at the leading edge were more influential for reaction force, head and minimum pressure, while the wrap angles had greater impact for efficiency. Furthermore, a multiple linear regression model was established to quantify the weight and trend of the influence of blade shape parameters on performance. The results provide a reference guide for the optimized design of centrifugal impeller to improve pump performance.
叶片形状参数对离心泵的性能有显著影响。为了揭示这些参数与泵性能之间的关系,以单通道为研究对象,通过数值模拟计算了其性能,并在实验台上进行了性能测量。提出了优化后的人工神经网络,并证明其具有较高的准确率。保留数千条后,总响应的人工神经网络相关系数可达0.997以上。通过灰色关联分析,找出了影响性能参数的种类和程度。结果表明,前缘叶片角对反作用力、扬程和最小压力的影响较大,而包叶角对效率的影响较大。建立了多元线性回归模型,量化了叶片形状参数对性能影响的权重和趋势。研究结果可为离心叶轮的优化设计提供参考指导,以提高泵的性能。
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引用次数: 0
Mori-Tanaka-based statistical methodology to compute the effective Young modulus of polymer matrix nano-composites considering the experimental quantification of nanotubes dispersion and alignment degree 基于mori - tanaka的统计方法计算聚合物基纳米复合材料的有效杨氏模量,考虑纳米管的分散和排列度的实验量化
Q2 Materials Science Pub Date : 2022-01-01 DOI: 10.5267/j.esm.2021.9.002
I. Patiño, C. Isaza
This paper presents a Mori-Tanaka-based statistical methodology to predict the effective Young modulus of carbon nanotubes (CNTs)-reinforced composites considering three variables: weight content, reinforcement dispersion and orientation. Last two variables are quantified by two parameters, namely, free-path distance between nano-reinforcements and orientation angle regarding the loading direction. To validate the present methodology, samples of multi-walled CNTs (MWCNTs)-reinforced polyvinyl alcohol (PVA)-matrix composite were manufactured by mixing solution. The MWCNT/PVA Young modulus was measured by nano-indentation, while the MWCNTs Young modulus was quantified by micro-Raman spectroscopy. Both stretched and unstretched composite specimens were fabricated. Transmission electron microscopy (TEM) and in-plane image analysis were used to obtain fitting coefficients of log-normal frequency distribution functions for the free-path distance and orientation angle. It was evidenced that numerical results fit well to measured values of effective Young modulus of MWCNTs and MWCNT/PVA, with exception of some particular cases where significant differences were found. Microstructural heterogeneities, cluster formation, polymer chains alignment, errors associated with the dispersion, orientation and mechanical characterization procedures, as well as idealization and statistical errors, were identified as possible causes of these differences. Finally, using the proposed methodology and the dispersion and orientation distribution functions experimentally obtained, the effective Young modulus is estimated for three kinds of thermoplastic matrices (polyvinyl alcohol, polyethylene ketone, and ultra-high molecular weight polyethylene) with different kinds of nanotubes (single wall, double wall, and multi-walled), at different weight contents, finding the superior mechanical performance for double-walled CNTs-reinforced composites and the lower one for multi-walled CNTs-reinforced ones.
本文提出了一种基于mori - tanaka的统计方法来预测碳纳米管(CNTs)增强复合材料的有效杨氏模量,该方法考虑了三个变量:重量含量、增强体分散和取向。最后两个变量由两个参数量化,即纳米增强材料之间的自由路径距离和加载方向的取向角。为了验证目前的方法,通过混合溶液制备了多壁碳纳米管(MWCNTs)增强聚乙烯醇(PVA)基复合材料样品。MWCNTs /PVA杨氏模量采用纳米压痕法测定,MWCNTs杨氏模量采用微拉曼光谱法测定。制作了拉伸和未拉伸的复合材料试样。利用透射电子显微镜(TEM)和平面图像分析获得了自由路径距离和取向角的对数正态频率分布函数的拟合系数。结果表明,数值结果与MWCNTs和MWCNT/PVA有效杨氏模量的实测值吻合良好,但在某些特殊情况下存在显著差异。微观结构的异质性、簇的形成、聚合物链的排列、与分散、取向和机械表征过程相关的误差,以及理想化和统计误差,被认为是造成这些差异的可能原因。最后,利用本文提出的方法和实验得到的色散和取向分布函数,对三种热塑性基质(聚乙烯醇、聚酮和超高分子量聚乙烯)在不同质量含量下的有效杨氏模量进行了估算,得到了不同种类的纳米管(单壁、双壁和多壁)。发现双壁碳纳米管增强复合材料的力学性能优越,而多壁碳纳米管增强复合材料的力学性能较差。
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引用次数: 2
Design and kinematic simulation of automated mechanism for shallot planting 大葱种植自动化机构的设计与运动学仿真
Q2 Materials Science Pub Date : 2022-01-01 DOI: 10.5267/j.esm.2022.2.003
C. H. Phi, Longji Dang, Hau Le Trung
The mechanization-oriented technology for shallot planting is a suitable solution which has a positive impact on changing the style of farming and reducing labor costs and increasing the efficiency in the process of planting shallot. In this research using an automatic planting device, the kinematics of shallot seed feed roller is calculated, designed and surveyed for correct positioning of the shallot in the created hole. This is done by the aid of Autodesk Inventor Professional and Matlab Simulink software. Working principle Diagram of planting shallot device is presented and the design parameters were optimized, and the stability of the suspension system used in the device was investigated.
大葱种植机械化技术是一种适合的解决方案,对改变种植方式,降低大葱种植过程中的劳动力成本,提高大葱种植效率具有积极的影响。本研究采用一种自动种植装置,对大葱送种辊进行运动学计算、设计和测量,以保证大葱在所造孔内的正确定位。这是通过Autodesk Inventor Professional和Matlab Simulink软件的帮助完成的。给出了大葱种植装置的工作原理图,对其设计参数进行了优化,并对装置所用悬挂系统的稳定性进行了研究。
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引用次数: 0
Mathematical modelling for multiple straight cracks with coalesced yield zones 具有合并屈服区的多个直裂缝的数学建模
Q2 Materials Science Pub Date : 2022-01-01 DOI: 10.5267/j.esm.2022.6.006
N. Akhtar, S. Hasan, S. Shekhar
Solution for a normally loaded infinite isotropic plate containing five cracks with coalesced yield zones is obtained using a complex variable method. Influence of coalesced yield zones on the load bearing capability of the infinite plate is analyzed. Analytical expressions for stress intensity factors, displacement components and crack opening displacement (COD) are obtained. Numerical study is carried out to determine the yield zone length, applied load ratio and COD. The numerical results are reported graphically between some important parameters.
用复变量法得到了含5条裂纹的无限各向同性板的正常加载解。分析了合并屈服区对无限板承载能力的影响。得到了应力强度因子、位移分量和裂纹张开位移(COD)的解析表达式。通过数值研究确定了屈服区长度、外加荷载比和COD。数值结果以图表形式报告了一些重要参数之间的关系。
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引用次数: 0
Prediction of tensile strength of fused deposition modeling (FDM) printed PLA using classic laminate theory 应用经典层压理论预测熔融沉积(FDM)打印PLA的拉伸强度
Q2 Materials Science Pub Date : 2022-01-01 DOI: 10.5267/j.esm.2021.12.002
S. R. Rajpurohit, H. Dave, K. Rajurkar
The application of Fused Deposition Modeling (FDM) is restricted due to limited information about the mechanical properties of printed parts. Therefore, it is required to determine the mechanical properties of the FDM properties to avail the full benefit of the FDM process. In the present study, Classic Laminate Theory (CLT) has been employed at the different configurations of layer thickness and raster width. The required elastic constant of material for CLT has been experimentally obtained through FDM printed Polylactic Acid (PLA) unidirectional specimens at 0°, 45° and 90° for different combinations of layer height and raster width. For these different combinations of layer height and raster width, constitutive models were developed to predict the tensile properties of the PLA parts. Tensile strength of the FDM printed bi-directional specimens has been experimentally obtained to validate the proposed CLT model results. The experimental tensile strength data is in good agreement with the data predicted by the proposed CLT model. Higher tensile strength and modulus were achieved with 0° raster angle compared to 90° raster angle. In the case of a bi-directional printed specimen, higher tensile strength was obtained with 45°/-45° raster angle followed by 30°/-60° and 0°/90° raster angle.
由于对打印件力学性能的了解有限,限制了熔融沉积建模(FDM)的应用。因此,需要确定FDM性能的机械性能,以充分利用FDM工艺的优势。在本研究中,经典层压理论(CLT)被用于不同层厚和栅格宽度的配置。通过FDM打印的聚乳酸(PLA)单向试样,在0°、45°和90°的不同层高和栅格宽度组合下,实验获得了CLT材料所需的弹性常数。针对这些不同的层高和栅格宽度组合,开发了本构模型来预测PLA零件的拉伸性能。实验获得了FDM打印双向试件的抗拉强度,以验证所提出的CLT模型结果。试验抗拉强度数据与所提出的CLT模型预测的数据吻合较好。与90°栅格角相比,0°栅格角获得了更高的拉伸强度和模量。在双向打印样品的情况下,45°/-45°光栅角、30°/-60°和0°/90°光栅角的拉伸强度更高。
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引用次数: 4
期刊
Engineering Solid Mechanics
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