Optimization Design of the Multi-Layer Cross-Sectional Layout of An Umbilical Based on the GA-GLM

Marine umbilical is one of the key equipment for subsea oil and gas exploitation,which is usually integrated by a great number of different functional components with multi-layers.The layout of these components directly affects manufacturing,operation and storage performances of the umbilical.For the multi-layer cross-sectional layout design of the umbilical,a quantifiable multi-objective optimization model is established according to the operation and storage requirements.Considering the manufacturing factors,the multi-layering strategy based on contact point identification is introduced for a great number of functional components.Then,the GA-GLM global optimization algorithm is proposed combining the genetic algorithm and the generalized multiplier method,and the selection operator of the genetic algorithm is improved based on the steepest descent method.Genetic algorithm is used to find the optimal solution in the global space,which can converge from any initial layout to the feasible layout solution.The feasible layout solution is taken as the initial value of the generalized multiplier method for fast and accurate solution.Finally,taking umbilicals with a great number of components as examples,the results show that the cross-sectional performance of the umbilical obtained by optimization algorithm is better and the solution efficiency is higher.Meanwhile,the multi-layering strategy is effective and feasible.The design method proposed in this paper can quickly obtain the optimal multi-layer cross-sectional layout,which replaces the manual design,and provides useful reference and guidance for the umbilical industry.

Optimization of Energy Density in Girders under Pure Bending with an Extruded Monolithic Cross-Section

This article proposes use of extruded compound materials with optimized resistant cross-sections as an alternative, in this case, seeking the maximum energy density as a design criterion. The advantage of this proposal is that it extends the life cycle and decreases fatigue issues.

The Optimal Cross-section Design of the “Trapezoid-V” Shaped Drainage Canal of Viscous Debris Flow

Debris flow drainage canal is one of the most widely used engineering measures to prevent and manage debris flow hazards.The shape and the sizes of the cross-section are important parameters when design debris flow drainage canal.Therefore,how to design the appropriate shape and sizes of the cross-section so that the drainage canal can have the optimal drainage capacity is very important and few researched at home and abroad.This study was conducted to analyze the hydraulic condition of a Trapezoid-V shaped drainage canal and optimize its cross-section.By assuming characteristic sizes of the cross-section,the paper deduced the configuration parameter of the cross-section of a Trapezoid-V shaped debris flow drainage canal.By theory analysis,it indicates that the optimal configuration parameter is only related to the side slope coefficient and the bottom transverse slope coefficient.For this study,the Heishui Gully,a first-order tributary of the lower Jinsha River,was used as an example to design the optimal cross-section of the drainage canal of debris flow.

Optimal Cross-Sectional Shape of Gas/Air Ducts

In industrial plants, ships, and buildings, a large amount of gas and air ducts are applied for equipment connection, HVAC, medium transport, and exhaust, etc. These ducts can be designed in varied cross-sectional shapes, such as round or rectangle. The author reveals through geometric calculation of the duct cross-sectional shapes and engineering experiences that the round cross-section is an optimal shape in the duct system. The round duct has the shorter perimeter than the other cross-sectional shape ducts and the stronger structure in the same working condition. The material saving of the round duct due to the shorter perimeter is quantitatively determined. In the pater, it is shown that the round duct is economically attractive. The economic analysis for the material cost saving is illustrated by an example. For a long duct system, the material and material cost savings are significant. It is suggested that the round duct in the gas and air duct system should have priority as long as the field conditions are allowed. In the paper, the material cost saving is also converted to PW, AW, and FW used for LCC economic analysis.

椭圆形橡胶堆结构优化研究

分析了某型机车用椭圆形二系橡胶堆应用中倾斜问题的原因,提出了结构改进措施以及解决其垂向与横向刚度匹配问题。通过对运行工况边界条件和既有结构问题分析,结合底孔设计与合适橡胶硬度进行刚度补偿等优化,调整了垂向和横向刚度匹配。对比两种结构有限元仿真分析结果表明:优化结构垂向与横向刚度匹配良好,橡胶应变降低9.1%~20.7%,疲劳损伤值降低36.6%,寿命提升;经疲劳试验验证,通过优化橡胶堆结构,预计可满足架修期内免维护,改善机车运行平稳性与安全性,解决车体倾斜问题。此次优化为多层橡胶堆产品提供经验,底孔可有效调节垂向与横向刚度比。随着底孔直径的增加,垂向刚度削弱比例约为横向刚度的2.5~3.5倍。橡胶硬度对垂向和横向刚度的影响相反,通过差位补偿可实现最佳设计。

凹槽叶顶参数化椭圆孔冷却布局多变量气热优化研究

为进一步提升凹槽叶顶椭圆孔及参数化组合偏转角的应用前景,建立了降维Kriging代理模型指导多目标遗传算法更新种群的优化算法流程,设计了帕累托前沿局部搜索策略,以最大化气膜冷却效率、最小化泄漏流量为设计目标,耦合稳态RANS数值计算方法,开展了多变量凹槽叶顶冷却布局优化与分析。研究结果显示,凹槽叶顶椭圆孔耦合大角度的正轴向偏转角与负径向偏转角能显著增强气膜贴壁性、大幅提升气膜覆盖范围,同时引导射流向凹槽下游堆积,提升凹槽尾缘处的局部阻塞效应。适当调整部分冷却孔径向偏转角度可以在保持大范围的气膜扩散幅度及均匀的冷却效率分布的前提下,促进泄漏流量进一步降低。优化结构相比圆形孔参考结构的气膜冷却效率提升了436.3%,泄漏流量相对降低了2.141%。

Concurrent topology optimization design of stiffener layout and cross-section for thin-walled structures

Stiffened plates or shells are widely used in engineering structures as primary or secondary load-bearing components.How to design the layout and sizes of the stiffeners is of great significance for structural lightweight.In this work,a new topology optimization method for simultaneously optimizing the layout and cross-section topology of the stiffeners is developed to solve this issue.The stilfeners and base plates are modeled by the beam and shell elements,respectively,significantly reducing the computational cost.The Giavotto beam theory,instead of the widely employed Euler or Timoshenko beam theory,is applied to model the stiffeners for considering the warping deformation in evaluating the section stiffness of the beam.A multi-scale topology optimization model is established by simultaneously optimizing the layout of the beam and the topology of the cross-section.The design space is significantly expanded by optimizing these two types of design variables.Several numerical examples are applied to illustrate the validity and effectiveness of the proposed method.The results show that the proposed two-scale optimization approach can generate better designs than the single-scale method.

A Two-Level Cross-Sectional Optimization Approach for Automotive Body Concept Design

Concept design is vital important in development of auto-body and it has great effects on later design work.In this paper,a twolevel cross-sectional optimization approach is presented to shorten concept design cycles.First,an exact structural analysis approach for spatial semi-rigid framed structures,i.e.,the transfer stiffness matrix method proposed in our previous study,is adopted for both static and dynamic analyses of body-in-white(BIW)structure.A two-level cross-sectional optimization approach is then proposed for an automotive BIW lightweight design,and genetic algorithm is used to solve the optimization models.Afterward,an object-oriented MATLAB toolbox,using distributed parallel computing techniques,is developed to promote the concept design of the BIW structure.Finally,relevant numerical examples demonstrate the validity and accuracy of the proposed method.

Optimization of structural parameters for elliptical cross-section spiral equal-channel extrusion dies based on grey theory

The elliptical cross-section spiral equal-channel extrusion （ECSEE） process is simulated by using Deform-3D finite element software. The ratio m of major-axis to minor-axis length for ellipse-cross-section, the torsion angle u, the round-ellipse cross-section transitional channel L1, the elliptical rotation cross-section transitional channel L2 and the ellipse-round cross-section transitional channel L3 are destined for the extrusion process parameters. The average effective strain eave on cross-section of blank, the deformation uniformity coefficient a and the value of maximum damage dmax are chosen to be the optimize indexes, and the virtual orthogonal experiment of L16 （45） is designed. The correlation degree of the process factors affecting eave, a and dmax is analyzed by the numerical simulation results using the weights and grey association model. The process parameters are optimized by introducing the grey situation decision theory and the ECSEE optimal combination of process parameters is obtained： u of 120 , m of 1.55, L1 of 7 mm, L2 of 10 mm, and L3 of 10 mm. Simulation and experimental results show that the material can be refined with the optimized structural parameters of die. Therefore, the optimization results are satisfactory.

大型搅拌反应器封头顶部结构优化设计

针对某大型搅拌反应器封头上搅拌法兰的偏转量过大的问题,提出了在封头顶部设置筋板以满足法兰偏转量的设计要求。采用ANSYS Workbench有限元分析软件,对筋板高度与长度的变化进行了参数化建模,得到了筋板的高度、长度与其最大应力之间的变化规律。结果发现筋板高度越低,其最大应力越小。而筋板的长度变大,其最大应力则先增大后逐渐减小,当长度达到某一值时最大应力趋于平稳,最终确定了筋板优化的高度和长度尺寸。

柔性保温墙椭圆管单管拱架日光温室内力分析及结构优化

针对柔性材料围护椭圆管单管拱架日光温室跨度不断加大,而标准化管材市场供应截面单一带来的结构安全性问题,该研究基于北京地区的风、雪荷载,依据国家标准《农业温室结构荷载规范》(GB/T 51183-2016)和《农业温室结构设计标准》(GB/T 51424-2022),选用截面80 mm×30 mm×2.0 mm(高×宽×壁厚)椭圆管,以12 m跨度日光温室为基准,使用Midas-Gen有限元软件建立模型,分析不同作物吊挂模式、后墙立柱不同结构形式以及拱架与基础不同连接形式对结构内力分布的影响,寻找结构最大应力最小的作物吊挂模式和结构形式。结果显示:柱脚铰接的单管拱架作物荷载2点吊挂时,出现强烈的局部应力集中,且作物荷载为主要控制荷载。其中后墙立柱作物吊挂点位置最大应力值为1146.7 N/mm^(2),其余位置平均应力值为445.4 N/mm^(2)。作物荷载为3个吊挂点时,拱架应力系数为0.61,作物荷载退化为次要控制荷载;吊挂点个数≥4时,拱架应力系数降低到约0.51,作物荷载完全退出控制作用,拱架最大应力仍超出材料允许强度。因此,采用局部加强措施同时结合柱脚连接形式寻找更加合理的拱架结构,并最终提出该温室结构采用前柱脚铰接、后柱脚固接、后墙立柱为格构柱时结构的最大应力最小,应力分布最合理。研究可为北京地区柔性保温墙椭圆管单管拱架日光温室的结构形式和结构用材提供参考。

纵向涡强化换热的优化设计及机理分析

对带纵向涡发生器的椭圆管翅片换热器空气侧表面的换热和流动特性进行了三维数值模拟.深入分析了纵向涡对流场和温度场的影响,并通过场协同原理揭示了纵向涡强化换热的根本机理,即减小了速度和温度梯度之间的夹角,改善了速度场和温度场的协同性.在此基础上,对纵向涡发生器的布置位置(上游布置和下游布置)和纵向涡发生器的攻角α(15°,30°,45°,60°)进行了优化设计.结果表明:当纵向涡发生器布置于换热管下游时,具有更好的强化换热能力;在纵向涡发生器采用下游布置的前提下,当纵向涡发生器的攻角α=30°时,具有最佳的强化换热能力.

类椭圆吊臂结构优化设计与研究

吊臂轻量化是进行吊臂结构优化设计的主要目标,但吊臂优化设计存在非线性程度高的特点,传统的优化方法很难得到全局最优解。首先建立了类椭圆吊臂有限元分析的参数化仿真模型,采用正交试验法建立样本数据,完成对BP神经网络的训练,建立了设计参数与目标向量之间的非线性映射关系。最后以吊臂重量最轻为优化目标,利用遗传算法寻优。优化结果表明,吊臂自重显著降低。该方法为以后复杂结构的轻量化设计提供了一种新的思路。

基于路面亮度系数表的路灯配光优化及透镜设计

本文参照了国际照明委员会CIE所颁布的路面亮度系数表,以C2路面为例讨论并设计了一种路灯的配光分布,同时满足较高的照度均匀度和路面亮度均匀度的要求,并获得了较高的能量效率Q(Lav/Eav)。基于此优化配光,采用笛卡尔椭球阵列设计了自由曲面透镜,在Dialux中验证了该透镜的配光性能,实现了UO=0.6,UL=0.7,UE=0.68,Q=0.088的照明效果,与预期结果基本一致。

椭圆形罩线型聚能装药结构参数正交优化研究

为获得椭圆形罩线型聚能装药较优的结构参数组合,运用正交设计方法对影响射流成型的主要结构参数进行优化设计,获得了不同的试验方案。利用ANSYS/LS-DYNA对各方案进行了数值模拟,得到了不同方案的最大射流速度和射流断裂前的最大长度,经对数值模拟结果分析获得了最佳的参数组合方案。各因素对射流速度和射流长度的影响规律由主至次分别为n→δ→a和n→a→δ,较优参数组合方案分别为n1-δ3-a1和n3-δ1-a1。

卵形齿轮与正弦机构的运动组合设计及其优化

提出一种以卵形齿轮为前置机构的近似等速移动机构。在讨论其运动组合方案之后 ,通过计算机编程优化卵形齿轮的基本参数 ,并进行速度误差分析 。

160t铁路救援起重机伸缩式吊臂有限元分析及优化

吊臂作为起重机的起吊支撑重要构件,其设计是否合理,直接影响起重机的承载能力、整机稳定性和整机自重。纵观国内外流动式起重机吊臂设计,大多数采用的截面形式是多边形截面。通过对截面形式的改进,采用了椭圆形截面吊臂设计。通过有限元软件ANSYS10.0,对160t铁路救援起重机吊臂进行分析计算。并且在此基础上对该伸缩式吊臂进行了优化,使吊臂力学性能满足要求。

螺旋扁管折流杆换热器壳侧性能多目标优化研究

基于遗传聚集响应面模型和多目标遗传算法,研究了以螺旋扁管为换热管的折流杆换热器结构参数、入口速度对壳侧流动和换热性能的影响,并对螺旋扁管折流杆换热器的性能进行了优化分析。结果表明:传热系数随螺距的增大先减小9.38%,后维持不变;在低入口速度条件下,随长短轴之比的增大而增大,在高入口速度条件下,存在先减小后增大的趋势。压降随螺距的增大基本不变;随长短轴之比的增大减小了36.67%。由敏感性分析可知传热系数和压降对入口速度的变化最敏感,截面椭圆长短轴之比次之,对螺距最不敏感。优化后的螺旋扁管折流杆换热器结构比原结构单位压降下的传热系数平均提高了26.42%。

基于几何变换的拱轴线的构成与特性研究

为了获得一种易于调控、具有较好力学性能的拱,该文对新型拱轴线的形成与特性展开了研究。通过在单一平面场中对椭圆进行几何变换,产生了一种新型曲线———椭变曲线。该文以椭变曲线作为拱轴线构建了一种新拱。通过应用软件(SolidWorks)仿真实验验证,结果表明:当拱的高度与跨度比值较大时,该拱的抗变形能力和抗压能力要优于其他常见拱;同时,这种新型拱轴线也具有很好的调控性能,可实现拱的结构优化。

非概率可靠性理论在机械臂架设计中的应用分析

以轮式起重机六边形箱形截面臂架为对象,对1 0 0吨汽车起重机椭圆截面臂架进行非概率可靠性优化,使其强度、刚度和稳定性满足非概率可靠度的条件下,重量最轻;并对椭圆截面中的大圆直径、顶边长度和圆心到顶边距离三者关系进行了分析,得出三者协同变化及独自变化时对臂架重量和可靠度的影响,为设计者提供了有力的参考依据。