Performance-driven design methodology for habitation shell design in extreme conditions on Mars

The research project illustrates how performance-driven design tools can be conducted as an architectural design methodology that suggests an innovative approach to design a habitation shell in extreme environmental conditions without human assistance.This research study attempts to use environmental data revealed by NASA and its habitat design requirements to develop a conceptual design for an innovative habitation form and then simulate it with Mars conditions to analyze the habitation shell’s structural behavior according to finite element analysis.In this regard,research phases,including layout configuration,form-finding,and structural analysis,have been conducted to explore a habitation concept implemented with generative design tools as a decision-maker in extreme conditions.In conclusion,two generated typologies of proposed habitation forms will be compared in terms of their structural performance under extreme loads of the martian environment.Within this research project,due to the numerous extreme challenges of design and construction of habitation in extreme conditions using conventional approaches,a performance-driven design methodology will provide a rational and sustainable design methodology to tackle extreme barriers to Mars’s environment.

Structural optimum design of bistable cylindrical shell for broadband energy harvesting application

The shallow cylindrical structure is suitable to develop broadband vibration energy harvesters due to the property of the inherent mechanical bistability. In this letter, the optimum design of the bistable cylindrical shell for broadband energy harvesting application is investigated from the structural point of view. The output power is evaluated by the concept of the harvestable power, which balances the frequency of snap through and the referred output energy associated with each snap through. The non- dimensional harvestable power is analytically expressed as the function of the non-dimensional curvature parameter and one constructed parameter. The universal dependence of the optimal curvature parameter and the associated optimal harvestable power on the constructed parameter is derived, which can be well aooroximated by the linear relation in double logarithmic coordinate.

Key Techniques and Applications of Adaptive Growth Method for Stiffener Layout Design of Plates and Shells

The application of the adaptive growth method is limited because several key techniques during the design process need manual intervention of designers. Key techniques of the method including the ground structure construction and seed selection are studied, so as to make it possible to improve the effectiveness and applicability of the adaptive growth method in stiffener layout design optimization of plates and shells. Three schemes of ground structures, which are comprised by different shell elements and beam elements, are proposed. It is found that the main stiffener layouts resulted from different ground structures are almost the same, but the ground structure comprised by 8-nodes shell elements and both 3-nodes and 2-nodes beam elements can result in clearest stiffener layout, and has good adaptability and low computational cost. An automatic seed selection approach is proposed, which is based on such selection rules that the seeds should be positioned on where the structural strain energy is great for the minimum compliance problem, and satisfy the dispersancy requirement. The adaptive growth method with the suggested key techniques is integrated into an ANSYS-based program, which provides a design tool for the stiffener layout design optimization of plates and shells. Typical design examples, including plate and shell structures to achieve minimum compliance and maximum bulking stability are illustrated. In addition, as a practical mechanical structural design example, the stiffener layout of an inlet structure for a large-scale electrostatic precipitator is also demonstrated. The design results show that the adaptive growth method integrated with the suggested key techniques can effectively and flexibly deal with stiffener layout design problem for plates and shells with complex geometrical shape and loading conditions to achieve various design objectives, thus it provides a new solution method for engineering structural topology design optimization.

Design optimization of a torpedo shell structure

An optimized methodology to design a more robust torpedo shell is proposed. The method has taken into account reliability requirements and controllable and uncontrollable factors such as geometry, load, material properties, manufacturing processes, installation, etc. as well as human and environmental factors. The result is a more realistic shell design. Our reliability optimization design model was developed based on sensitivity analysis. Details of the design model are given in this paper. An example of a torpedo shell design based on this model is given and demonstrates that the method produces designs that are more effective and reliable than traditional torpedo shell designs. This method can be used for other torpedo system designs.

Design of Steam Turbine for Electric Power Production Using Heat Energy from Palm Kernel Shell

The steam turbine is a prime mover that converts kinetic energy in steam into rotational mechanical energy through the impact or reaction of the steam against the blades. The aim of this study is to design a steam turbine for a small scale steam power plant with target of producing electricity. The turbine is driven by the heat energy from palm kernel shells as a renewable energy source obtained at a lower or no cost. The study was concentrated on design of turbine elements and its validation using computer packages. Specifically, the microturbine design was limited to design, modeling, simulation and analysis of the rotor, blades and nozzle under the palm kernel shell as fuel for the micro power plant. In blade design, stress failures, efficiency and blade angle parameters were considered. In casing volume design, the overall heat transfer and mean temperature, and different concepts were applied. The thermal distribution on stator and rotor was considered in order to determine its level of tolerance. The design software packages used for design validation were Solidworks and Comsol Multiphysics for analysis. Simulation results showed that the designed steam turbine can adequately tolerate change in stress/load, torsion/compression, temperature and speeds.

Design Scheme of New Type Shell Raising and Feeding System of Medium-large Caliber Naval Gun

The medium -large caliber naval gun is still playing an important role in modern war. The development of highly automatic Shell Raising and Feeding System (SRFS) in the world has been briefly outlined. Several typical SRFS of medium-large caliber naval guns have been analyzed. A re-design of the system is introduced, in which systematic design method has been used to demonstrate its feasibility. The design goal of the system is to realize rapid shell feeding, with application to many types of shells, quick change of shell types , accurate and reliable feeding operation, simple mechanical structure and easy realization of shell withdrawing.

一种剃须刀外壳注塑模具设计

以一种剃须刀外壳的设计为基础,通过分析产品结构特征,设计了一模两腔,动、定模多个斜向复杂抽芯的结构,并运用模流分析软件模拟产品的填充、保压、冷却过程。发现该模具结构设计合理,开合模动作准确可靠,多个斜向抽芯之间无干涉,产品成型表面质量较好,可以达到客户的需求。模具结构新颖,可以为同类设计提供借鉴。

基于Aspen EDR的管壳式换热器工艺选型设计教学实践

管壳式换热器工艺选型设计是化工过程中设备设计的重要环节之一。为了避免手工计算中繁琐的计算和复杂的校核问题,以无相变的乙醇冷却器为例,探讨Aspen EDR软件在管壳式换热器工艺选型设计中的实践应用。通过Aspen EDR软件的教学示范,激发学生学习积极性和主动性,提升学生运用理论知识分析和解决复杂化学工程问题的能力,强化专业软件应用能力。

基于壳单元的盾构隧道参数化结构计算与验证

三维壳单元较二维梁单元能更精细地模拟管片结构受土体作用下的力学行为。为了推广三维壳单元隧道结构计算模型在大直径盾构隧道结构计算中的应用,提出基于壳单元的参数化隧道结构建模方法(Shell element-based Parametric Tunnel Structure Modeling,SPTSM)。SPTSM基于隧道中轴线及截面半径参数,能自动生成由壳单元所组成的隧道模型。在模型中,相邻环之间的壳单元公共边被定义成线性铰,以此模拟管片环缝间的接头刚度;管片纵缝间的接头刚度通过均质圆环法引入折减系数进行替代;壳单元节点被施加荷载压力、地层弹簧及约束支座,以模拟管片结构与围岩之间的力学行为。SPTSM提供了结构自动建模算法和壳单元节点荷载的自动计算算法,并通过调用Karamba3D有限元结构计算内核,实现盾构隧道结构的建模−计算一体化。将SPTSM应用于杭州某大直径盾构隧道工程76 m区间段,对比结构变形的计算和实际检测结果,验证SPTSM的合理性。SPTSM能自动建立精细的三维壳单元盾构隧道结构模型,并同时完成荷载压力、地层弹簧、线性−铰刚度以及约束支座的布置和设定。对比点云扫描的结构位移检测结果和SPTSM计算出的结构变形结果,SPTSM输出的结构变形云图属于合理范围,结合SPTSM输出的内力云图和荷载分布云图,SPTSM可以近似反映隧道结构局部位置的变形或位移趋势。综上,SPTSM可为盾构隧道的智能化结构设计提供有力支撑。

新能源减速器壳体结构设计与轻量化研究

2021年新能源汽车销量330万辆,渗透率14.8%;2022年,汽车总销量2686.4万辆,新能源汽车总销量688万辆,同比增长2.08倍,渗透率25.6%。传统汽车厂及造车新势力都加大了在电动汽车领域的投入。在纯电动汽车竞争日益激烈环境下,加快了产品向高续航、高集成、轻量化等方向的发展。对新能源电驱动系统功率密度、高性价比等方面提出更高需求。为顺应行业快速发展趋势,在满足功能与强度要求下,对减速器进行轻量化设计,是产品设计开发需要重点考虑的方面。

基于等几何法和模拟退火的复杂壳结构分析及优化

本文提出了一种基于等几何法和模拟退火的壳结构分析及优化算法,旨在提高复杂壳结构的CAD与CAE一体化设计效率。首先基于NURBS技术对薄壳结构进行适分析参数化建模,然后基于Kirchhoff-Love壳理论实现等几何分析。接着,基于模拟退火算法以壳体的几何参数为设计变量,以多项力学性能为目标函数进行优化,实现了等几何分析与智能优化算法相结合的壳结构分析与优化。最后,通过2个算例验证了该算法的有效性。相对于传统有限元方法,该算法具有高精度、高效率的优势。

深海无人系统大长径比环肋圆柱壳结构设计与试验研究

环肋圆柱壳是深海无人系统广泛采用的一种耐压结构形式,保障其结构安全是系统研制过程中非常重要的一环。针对环肋圆柱壳的结构特征推导了组合结构重量关系式和结构参数简化估算方法,并以一种超长型深海无人系统耐压结构为例,围绕大长径比环肋圆柱壳的结构形式、设计计算、仿真分析、模型验证等开展研究。研究表明提出的大长径比环肋圆柱壳结构设计参数简化估算方法具有较好的适应性。相关计算和分析结果可以为该型深海无人系统结构设计提供技术支撑,也可以为其他类似耐压结构设计提供参考。

基于协同优化的耐压柱壳多学科多目标优化

为提高耐压柱壳的设计效率和结构性能,本文基于多学科设计优化思想,进行了耐压柱壳多学科设计优化的学科分解,确定了耐压柱壳多学科优化设计的设计参数,明确了设计变量间的耦合关系,设计了耐压柱壳参数化分析流程,进行了设计变量灵敏度分析。在利用响应面模型建立了具有较高拟合精度耐压柱壳近似模型的基础上,以质量排水量比和极限载荷为目标函数,建立了基于协同优化方法的耐压柱壳多学科多目标优化模型,在确定了系统层和学科层的优化求解方法基础上,设计了基于协同优化的耐压柱壳多学科多目标优化框架,进行了优化的求解工作,得到了优化方案。与初始方案的对比表明:所得到的Pareto解集中,部分方案在2个目标函数上均得到了优化,验证了优化框架的有效性。

基于仿生原理的板壳结构加强筋优化设计

目的加强筋的合理分布可有效提升结构抗振性,为了提高板壳结构的抗振性能,本文基于仿生原理,以板壳加强筋分布为研究目标,进行动力学的优化与设计研究。方法采用自适应成长法,通过引入等效静态载荷法,建立以动柔度为目标的加强筋分布优化模型,推导出基于准则法的设计变量迭代更新公式,分别研究单点激励和多点不同动态载荷作用下板壳结构的加筋分布设计,并研究单点激励和多点不同动态载荷激励下的板壳加筋结构特性。结果研究结果表明,板壳结构加强筋采用仿生原理对其分布进行优化,可实现任意动态载荷作用下加强筋分布的设计,且优化的加强筋形态分布清晰,无须再处理即可应用到加强筋的生产制造中。结论根据对不同约束的板壳结构进行优化设计,通过加强筋的设计,提升了板壳结构的抗振性能。

脱壳间隙自由可调式花生脱壳装置设计与试验

针对现有脱壳间隙不可自由调节、机械损伤率高、花生品种适应性差等问题,设计了一款脱壳间隙自由可调式花生脱壳装置。脱壳装置上部采用导杆、导套、压缩弹簧等构成脱壳间隙自由可调揉搓摆臂,下部固定有编织筛网,上下装置组成的弧形腔室构成脱壳室;揉搓摆臂驱动装置由可调速电机带动曲柄摇杆机构进行往复揉搓运动。其中,为验证间隙自由可调揉搓摆臂运行可靠平稳性,对其需满足的设计要求进行验算,确定了当弹性装置高径比为3.7和弹簧许用安全系数为2.6时,满足作业要求;对曲柄摇杆机构的设计参数和脱壳运动状态进行运动学和脱壳力学分析研究,确定了当摇杆与竖直方向夹角为40°和弹簧压缩行程为12 mm时,弹簧装置可承受最大载荷为710 N,能够满足往复揉搓运动学和脱壳力学性能要求。最后以对该装置脱壳性能影响较大的可调速电机转速为试验因素,以豫花22为试验对象,进行脱壳性能试验。试验结果表明:当电机转速为1600 r·min^(-1)时,脱净率为98.6%,破损率为2.4%,发芽率为98.8%,满足行业花生脱壳质量要求。

压缩机机壳用低温高强韧铸钢材料研究

通过对材料合金成分及热处理工艺参数进行的实验室研究,确定了压缩机机壳低温高强韧钢材料的内控成分及热处理工艺参数,经造型、熔炼、浇注、清理、热处理、精整后,制造出符合用户图纸、技术要求的铸件。

基于midas Gen的单层球形网壳结构分析及应用研究

基于midas Gen软件模型,在不同应力比下对实体工程金属网壳模型进行分析,获得了工程实体金属网壳模型静力荷载下铸钢铰支座反力、罕遇地震时铸钢铰支座反力、静力荷载销轴反力、罕遇地震销轴反力分布情况。将设计模型得到的实体工程金属网壳荷载–位移曲线与有关设计模型网壳荷载–位移曲线进行对比,通过实体工程金属网壳模型设计实例,分析了不同应力下的杆件位移情况,从而证明了实体工程金属网壳模型设计的准确性及合理性。

基于ABAQUS的曳光管套结构设计与强度分析

曳光弹丸发射过程中,在高过载和高膛压作用下曳光管壳可能发生大的塑性变形甚至断裂,影响曳光药剂正常燃烧,因此设计了用来固定和保护曳光管的管套。压螺与弹体螺纹连接和曳光管壳在高过载作用下的强度校核结果满足要求的前提下,利用ABAQUS软件仿真分析曳光管壳和管套在360 MPa膛压作用下的应力应变,结果显示:曳光管与方案1管套配合时的最大应力为1026 MPa,最大应变为0.8;与方案2管套配合时的最大应力为844.7 MPa,最大应变为0.05。经分析可知,采用方案1管套时,曳光管壳的局部变形量可使曳光药剂断层、松散;而采用方案2管套时,曳光药剂强度不会发生破坏性变化。通过曳光性能射击试验验证了ABAQUS软件仿真分析结果。

基于CATIA的参数化混合构建技术方法与应用

针对传统建模方法无法在车身薄壁件设计开发过程中高效地进行数模后处理问题,提出了一种参数化混合构建技术。该技术在参数化关联设计的基础上,结合片体建模的灵活性与实体建模的顺序性来构建白车身薄壁件。文中阐述数模的参数化设计、关联设计、链接分析与元素发布等核心构建技巧。通过具体车身薄壁件设计案例,提出了对数模健壮性设计的要求,并展示了模板设计、元素发布和建模流程等前处理环节。最后,结合改变片体和实体特征,及元素特征转换的案例,展示了参数化混合构建技术的高效后处理能力,并将其与传统建模后处理技术进行对比,验证了该技术在车身薄壁件设计领域具备建模结构健壮、操作简洁和后处理高效的特点。