Web Layout Design of Large Cavity Structures Based on Topology Optimization

Large cavity structures are widely employed in aerospace engineering, such as thin-walled cylinders, blades andwings. Enhancing performance of aerial vehicles while reducing manufacturing costs and fuel consumptionhas become a focal point for contemporary researchers. Therefore, this paper aims to investigate the topologyoptimization of large cavity structures as a means to enhance their performance, safety, and efficiency. By usingthe variable density method, lightweight design is achieved without compromising structural strength. Theoptimization model considers both concentrated and distributed loads, and utilizes techniques like sensitivityfiltering and projection to obtain a robust optimized configuration. The mechanical properties are checked bycomparing the stress distribution and displacement of the unoptimized and optimized structures under the sameload. The results confirm that the optimized structures exhibit improved mechanical properties, thus offering keyinsights for engineering lightweight, high-strength large cavity structures.

ESD performance of LDMOS with source-bulk layout structure optimization

To enhance the robustness of LDMOS ESD protection devices, the influence of a source-bulk layout structure is analyzed by theoretical analysis and numerical simulation. Novel structures with varied source-bulk layout structures are fabricated and compared. As demonstrated by TLP testing, the optimized structure has an 88% larger It2 than a conventional one, and its Vtl is reduced from 55.53 to 50.69 V.

A modified stiffness spreading method for layout optimization of truss structures

The stiffness spreading method (SSM) was initially proposed for layout optimization of truss structures,in which an artificial elastic material of low modulus is uniformly distributed in the design domain to create connections between discrete members.In this paper,a modified stiffness spreading method is proposed by replacing the artificial elastic material with auxiliary bars to connect real members of the truss structure.Since the background continuum mesh for the elastic material is no longer required,the computational cost is significantly reduced.Like SSM,the new method is advantageous in that an initial design may consist of disconnected bars allocated in the design domain,and mathematical programming methods can be applied for the efficient solution of the formulated optimization problem.A number of solution strategies are also developed to achieve more practical designs with lower computational cost.Numerical examples of both 2-D and 3-D truss structures are presented to demonstrate the feasibility,robustness and effectiveness of the proposed method.

THE LAYOUT OPTIMIZATION OF STIFFENERS FOR PLATE-SHELL STRUCTURES

The plate-shell structures with stiffeners are widely used in a broad range of engineering structures. This study presents the layout optimization of stiffeners. The minimum weight of stiffeners is taken as the objective function with the global stiffness constraint. In the layout optimization, the stiffeners should be placed at the locations with high strain energy/or stress. Conversely, elements of stiffeners with a small strain energy/or stress are considered to be used inefficiently and can be removed. Thus, to identify the element efficiency so that most inefficiently used elements of stiffeners can be removed, the element sensitivity of the strain energy of stiffeners is introduced, and a search criterion for locations of stiffeners is presented. The layout optimization approach is given for determining which elements of the stiffeners need to be kept or removed. In each iterative design, a high efficiency reanalysis approach is used to reduce the computational effort. The present approach is implemented for the layout optimization of stiffeners for a bunker loaded by the hydrostatic pressure. The numerical results show that the present approach is effective for dealing with layout optimization of stiffeners for plate-shell structures.

APPROACH FOR LAYOUT OPTIMIZATION OF TRUSS STRUCTURES WITH DISCRETE VARIABLES UNDER DYNAMIC STRESS, DISPLACEMENT AND STABILITY CONSTRAINTS

A mathematical model was developed for layout optimization of truss structures with discrete variables subjected to dynamic stress, dynamic displacement and dynamic stability constraints. By using the quasi-static method, the mathematical model of structure optimization under dynamic stress, dynamic displacement and dynamic stability constraints were transformed into one subjected to static stress, displacement and stability constraints. The optimization procedures include two levels, i.e., the topology optimization and the shape optimization. In each level, the comprehensive algorithm was used and the relative difference quotients of two kinds of variables were used to search the optimum solution. A comparison between the optimum results of model with stability constraints and the optimum results of model without stability constraint was given. And that shows the stability constraints have a great effect on the optimum solutions.

Layout design and application of 4D-printing bio-inspired structures with programmable actuators

Four-dimensional(4D)printing is an advanced form of three-dimensional(3D)printing with controllable and programmable shape transformation over time.Actuators are used as a controlling factor with multi-stage shape recovery,with emerging opportunities to customize the mechanical properties of bio-inspired structures.The print pattern of shape memory polymer(SMP)fbers strongly afects the achievable resolution,and consequently infuences several other physical and mechanical properties of fabricated actuators.However,the deformations of bio-inspired structures due to actuator layout are more complex because of the presence of the coupling of multi-directional strain.In this study,the initial structure was designed from closed-shell behavior and divided into a general unit and actuator unit,the latter responsible for driving the transformation.Mutual stress confrontation between the actuator and the general unit was considered in the layout thermodynamic model,in order to eliminate the transformation produced by the uncontrolled shape memory behavior of the general unit.Three critical and efective strategies for the layout design of actuators were proposed and then applied to achieve the desired accurate deformation of 3D-printed bilayer structures.Finally,the proposed approach was validated and adopted for fabricating a complex shell-like gripper structure.

Current Research Situations,Problems and Recommendations of Land Use Structure and Layout Optimization

Land is the foundation for human survival and development,and all human social and economic activities are inseparable from the land as a space carrier.With the continuous development of China's social economy,China is facing new social development needs such as urban-rural integration and rural revitalization.At the same time,China starts to attach great importance to ecology and has proposed the concept that lucid waters and lush mountains are invaluable assets.In this situation,the rational use of land resources,the optimization of land use structure and layout are also facing new challenges and problems,and more comprehensive consideration is required to make relevant optimization.Using the method of literature comparative analysis,from the conceptual connotation,basic theory,method model,and specific practice of land use structure and layout optimization,this paper analyzed and summarized the current research situations and problems,and finally came up with recommendations for the future research.

Research and design of the main equipments and structure of Xiangjiaba shiplift

The type of pinion and rack vertical shiplifts has been developed in recent a couple of years in the construction of dams.But the design methods and methodologies have rarely been discussed in literature.The Xiangjiaba shiplift is the second shiplift of this type following the Three Gorges shiplift.Being aimed at the technological rationality of the design in synthetically considering security,economy and applicability,this paper presents the research results of some vital issues relating the design of the Xiangjiaba shiplift,including the determination of design water depth of ship chamber based on fluid numeral computation and physical model test,the optimum design of general layout of main equipments and the civil structure of the Xiangjiaba shiplift,the finite element method(FEM) analysis of stress,vibration modes and the buckling of ship chamber,antiseismic research and the design of structures and mechanisms of the shiplift and the optimum design of driving mechanisms.This research provides the theoretical basis for the design of the Xiangjiaba shiplift.The design principles and research methods are valuable for the design of the same type of shiplifts.

教育、科技、人才一体化背景下高教人才培养改革逻辑与路径

教育、科技、人才一体化发展是对世界教育、科技、人才发展与高等教育内在关系的规律性把握,对我国高等教育人才培养提出了新的使命与要求。高等教育人才培养改革逻辑从内涵式发展到高质量发展,从高教自身看待质量转向从科技人才战略和经济社会需求认识高等教育培养质量,加快人才培养改革,服务和支撑教育、科技、人才一体化发展。改革路径是实现人才培养层次结构的上移,提高研究生培养规模与质量;加快中国特色、世界一流的大学与优势学科建设,提高人才自主培养能力;优化高等教育布局结构,构建与世界重要人才中心和创新高地建设相适应的人才培养体系。

教育强国背景下中外合作办学提升高等教育国际影响力策略研究

在加快建设教育强国进程中,中外合作办学对提升高等教育国际影响力具有重要作用,且在提升拔尖创新人才培育力、国际学生吸引力、科研学术引领力、跨境教育“中国方案”影响力等方面具备了一定基础。然而,目前我国中外合作办学尚存在结构布局不够均衡、拔尖创新人才培养质量有待提高、服务国家和地方发展能力亟须提升、高效能治理体制机制尚需完善等问题。为此,中外合作办学应加大改革创新力度,补齐短板,在适度统筹规模和效益、调整优化结构布局,加大支撑保障力度、多渠道提升人才培养质量,聚焦科技前沿和国家关切、把好引进和审批准入关,完善合作办学治理体系、探索中国特色的合作办学模式等方面持续发力,不断提高中外合作办学水平,切实提升我国高等教育国际影响力。

新质生产力推动内蒙古产业结构优化升级的理论逻辑与路径

新质生产力与产业结构之间具有内在逻辑,它能够以新要素为产业结构优化调整注入创新活力。本文旨在分析新质生产力的内涵与特征,探讨新质生产力在推动内蒙古产业结构优化升级中的理论逻辑,结合内蒙古当前产业结构存在的问题,提出新质生产力推动内蒙古产业结构转型升级的路径,以期为内蒙古经济高质量发展提供理论和实践指导。

面向综合评估的船舶工装设计方法

针对船舶建造工装设计标准化程度低、设计不规范以及设计管理落后等问题,提出一种面向综合评估的工装设计方法。从工装库构建、智能设计、仿真评估与优化等角度开展工装数字化设计研究。基于工装模型库实现设计模型的有效管理和调用,并通过集成寻优算法实现工装最优布局,在此基础上基于有限元仿真和工艺仿真技术,结合具体指标,实现工装结构力学性能和工艺仿真评估,同时利用结构优化技术对设计结果进行优化,在满足使用需求的基础上降低了加工成本。基于达索三维体验平台开发数字化工装设计系统,固化设计流程,并通过分段吊马设计的实际应用,实现设计效率提升200%,同时重量减轻12.8%。

坚持“四水四定”推动经济社会高质量发展——以宁夏回族自治区“四水四定”创新实践为例

坚持“四水四定”,强化水资源刚性约束,既是缓解我国水资源供需矛盾、保障水安全的必然选择,也是推动高质量发展、建设美丽中国的客观要求。文章以宁夏回族自治区为例,深入分析了宁夏回族自治区“四水四定”改革实践,总结了相关经验启示,为探索以水资源节约集约利用推动经济社会高质量发展提供了参考。

成组立模成型机模板结构优化设计研究

混凝土预制构件成组立模成型机(简称成组立模)是一种新型的生产混凝土预制构件的设备。为了提高成组立模台面的振动效果和承载能力,本研究以成组立模模板结构为研究对象,提出了一种拓扑优化新兴设计与响应面法结合的优化设计理论。首先,基于变密度法对成组立模模板结构加强筋布局进行拓扑优化设计,得到了加强筋最佳的材料分布形式,以此对成组立模模板结构进行了结构优化设计。为得到最佳的加强筋设计参数,采用中心组合试验设计,建立模板结构最大位移、最大等效应力的响应面模型。利用多目标遗传算法对响应面模型进行优化求解,得出加强筋各参数最优的组合方案。有限元分析结果表明:与初始方案相比,优化设计方案提高了台面的刚度和强度,同时改善了模板结构的振动特性,并提高了混凝土预制构件的成型质量。该研究为进一步推进成组立模的研究提供了理论指导。

复杂地质条件下南疆某水库工程枢纽布置比选探讨

笔者以南疆某水库工程为例,对复杂地形地质条件下枢纽布置方案比选进行探讨。通过分析存在的不良地质情况,考虑泄水建筑物在高水头、高流速运行下的结构安全及右岸高边坡问题,拟定了3个枢纽布置方案。从地形地质条件、枢纽布置、水力学条件、运行管理、工程施工、工程投资等方面进行比较分析,选择合理紧凑的枢纽布置方案,为类似工程提供一定的参考。

苏州某大型复杂商业连体结构设计

苏州某大型商业综合体项目位于7度抗震设防烈度区,为体型重叠建筑。通过5道防震缝将建筑整体划分为购物中心A区、购物中心B区、停车楼、商业街A区、商业街B区五个独立结构单元。购物中心A区为复杂连体高层建筑,1~5层采用框架-剪力墙结构,两个单体在3~5层中区由钢桁架相连,顶部(6层)钢桁架结构与两个单体通过成品球铰支座连接,形成强连体结构。充分考虑了周期比、位移比双指标平衡后对购物中心A区剪力墙布置进行了优化;屋顶钢桁架结构支座采用变刚度设计,局部设置滑动支座解决恒载下杆件应力比较高的问题。通过性能化设计,该复杂结构连体部位可以满足中震弹性、大震不屈服的性能目标要求。性能化设计及专项分析表明,影院钢结构具有良好的抗震性能、楼盖舒适度及防倒塌性能。

成都天府国际机场航站区室外排水管道设计

介绍了成都天府国际机场航站区室外排水管道设计,重点分析了减少管道埋深的措施和结构基础对排水管道布置的影响。项目排水管道与传统建筑工程的排水管道相比,其管径更大,覆土更深,与市政排水管道相比,其安装受到更多的限制。针对狭窄空间,对传统跌水井进行改进,提出了一种尺寸更小、安装更灵活的跌水井方案。其中,设计了一种供多支管接入的矩形混凝土检查井,可有效减少支管检查井数量,节省造价。

大直径盾构隧道整体式预制弧形件构造

上海市机场联络线是国内首次在大直径盾构隧道中采用整体式预制弧形件的工程,而现阶段缺少对整体式预制弧形件选型及排版的研究。针对该问题,本文分析了标准环+左转弯环+右转弯环、左转弯环+右转弯环和通用楔形环三种管片形式下弧形件的构造设计,并给出排版计算方法。结果表明,在标准环+左转弯环+右转弯环和通用楔形环管片形式下,分别采用直线形+楔形弧形件和无楔形量的弧形件能较好满足工程需求,建议在类似工程中选用。

工程结构三维重建中数字影像采集基站布设优化

为优化无人机影像采集基站布设方式,以提高工程结构三维逆向建模效率。提出了控制参数BHR(breadth height ratio),设置了总计25组对比分析工况;然后设计了一个能够有效模拟实际工程结构三维重建情景的实验,对比了各工况在点定位,移动轨迹和线形变化3类特征测量的误差,从工作效率和模型精度两方面对基站的合理布设方式进行了评估;最后对一个装配式钢框架结构进行三维重建,以验证提出的最优布设方法在工程应用中的有效性。结果表明,25组工况在3类特征测量中表现出相似的规律,即误差随着BHR和拍摄距的下降而减小;25组工况的误差变化率有显著差异,其中拍摄距离>0.8 m的工况绝大多数表现出了负贡献;结合建模时间,综合评估最合理的布设方式为BHR=0.18,H=H_(eff)/2的工况,将其应用到实际工程中得到了良好的效果。所提出的无人机基站布设方式可以在保证三维重建精度的前提下大幅缩减建模时长。

新疆大豆生产与布局历史演变分析

新疆种植大豆历史悠久,是我国优质大豆产区。文章基于1 952—2023年新疆大豆生产统计和调研数据,运用描述性统计分析方法,从新疆大豆生产规模与产量、大豆空间生产布局及主要种植模式3个视角对新疆大豆生产在不同时段的发展变化特点和总体演变趋势进行分析。结果表明,新疆大豆生产规模和总产量先后经历稳中有增、大幅扩张、稳定发展、萎缩、恢复增长5个阶段,生产规模扩张对大豆产量贡献率均高于50%。单产变异系数高于全国及美国平均水平,但其贡献率整体较低。大豆生产由以地方为主转变为以兵团为主,空间布局由以昌吉州、塔城地区、伊犁州直为主转变为北有伊犁州直、南有喀什地区的新局面,种植模式由以早熟春播大豆为主转变为夏播为主,春播为辅。