A Hybrid Level Set Optimization Design Method of Functionally Graded Cellular Structures Considering Connectivity

With the continuous advancement in topology optimization and additive manufacturing(AM)technology,the capability to fabricate functionally graded materials and intricate cellular structures with spatially varying microstructures has grown significantly.However,a critical challenge is encountered in the design of these structures–the absence of robust interface connections between adjacent microstructures,potentially resulting in diminished efficiency or macroscopic failure.A Hybrid Level Set Method(HLSM)is proposed,specifically designed to enhance connectivity among non-uniform microstructures,contributing to the design of functionally graded cellular structures.The HLSM introduces a pioneering algorithm for effectively blending heterogeneous microstructure interfaces.Initially,an interpolation algorithm is presented to construct transition microstructures seamlessly connected on both sides.Subsequently,the algorithm enables the morphing of non-uniform unit cells to seamlessly adapt to interconnected adjacent microstructures.The method,seamlessly integrated into a multi-scale topology optimization framework using the level set method,exhibits its efficacy through numerical examples,showcasing its prowess in optimizing 2D and 3D functionally graded materials(FGM)and multi-scale topology optimization.In essence,the pressing issue of interface connections in complex structure design is not only addressed but also a robust methodology is introduced,substantiated by numerical evidence,advancing optimization capabilities in the realm of functionally graded materials and cellular structures.

Structural Optimization of Concrete Slab Frame Bridges Considering Investment Cost

The present study investigates computer-antomated design and structural optimization of concrete slab frame bridges considering investment cost based on a complete 3D model. Thus, a computer code with several modules has been developed to produce parametric models of slab frame bridges. Design loads and load combinations are based on the Eurocode design standard and the Swedish design standard for bridges. The necessary reinforcement diagrams to satisfy the ultimate and serviceability limit states, including fatigue checks for the whole bridge, are calculated according to the aforementioned standards. Optimization techniques based on the genetic algorithm and the pattern search method are applied. A case study is presented to highlight the efficiency of the applied optimization algorithms. This methodology has been applied in the design process for the time-effective, material-efficient, and optimal design of concrete slab frame bridges.

Failure mechanism of directional roof cutting and design method optimization

Directional roof cutting(DRC)is one of the key techniques in non-pillar coal mining with self-formed entries(NCMSE)mining method.Due to the inability to accurately measure the expansion coefficient of the goaf rock mass,the implementation of this technology often encounters design challenges,leading to suboptimal results and increased costs.This paper establishes a structural analysis model of the goaf working face roof,revealing the failure mechanism of DRC,and clarifies the positive role of DRC in improving the stress of the roadway surrounding rock and reducing the subsidence of the roof through numerical simulation experiments.On this basis,the paper further analyses the roadway pressure and roof settlement under different DRC design heights,and ultimately proposes an optimized design method for the DRC height.The results indicate that the implementation of DRC can significantly optimize the stress environment of the working face roadway surrounding rock.At the same time,during the application of DRC,three scenarios may arise:insufficient,reasonable,and excessive DRC height.Insufficient height will significantly reduce the effectiveness of the technology,while excessive height has little impact on the implementation effect but will greatly increase construction costs and difficulty.Engineering verification shows that the optimized DRC design method proposed in this paper reduces the peak stress of the protective coal pillar in the roadway by 27.2%and the central subsidence of the roof by 41.8%,demonstrating excellent application results.This method provides technical support for the further promotion of NCMSE mining method.

Structural Topology Optimization by Combining BESO with Reinforcement Learning

In this paper,a new algorithm combining the features of bi-direction evolutionary structural optimization(BESO)and reinforcement learning(RL)is proposed for continuum structural topology optimization(STO).In contrast to conventional approaches which only generate a certain quasi-optimal solution,the goal of the combined method is to provide more quasi-optimal solutions for designers such as the idea of generative design.Two key components were adopted.First,besides sensitivity,value function updated by Monte-Carlo reinforcement learning was utilized to measure the importance of each element,which made the solving process convergent and closer to the optimum.Second,ε-greedy policy added a random perturbation to the main search direction so as to extend the search ability.Finally,the quality and diversity of solutions could be guaranteed by controlling the value of compliance as well as Intersection-over-Union(IoU).Results of several 2D and 3D compliance minimization problems,including a geometrically nonlinear case,show that the combined method is capable of generating a group of good and different solutions that satisfy various possible requirements in engineering design within acceptable computation cost.

Study on optimal design to improve auto-body structural crashworthiness

In this paper the optimal model of the main energy absorbed structure in an auto-body “front rail”, based on structural crashworthiness is built. For an optimal design on structure crashworthiness, the new method is based on a response surface model and Pareto GA, which improves the efficiency and flexibility of an optimal design, that is brought forward. The traditional optimal method can not be applied in the design of an impact structure due to the high nonlinearity and large time cost of crashworthiness FE analysis. So the method of an optimal design based on crashworthiness is brought forward. After constructing the response surface model of auto-body crashworthiness, the Pareto GA can be applied to find the multi-objective globally. The optimal solution set can then be used to provide many scheme combinations for choice structural parameters.To acquire the optimized structure parameters on front rail crashworthiness, this simplified model of an original design is built. After studying various ways of reinforcing the cross-section to control the structural failure mode, a better method has been found. On the precondition of not increasing the mass of the structure, an optimal design of the front rail is performed further. Finally, the optimized scheme is implemented in the full-car impact analysis and crashworthiness is studied. With proper measures to control deformation of the front rail structure the crashworthiness can be improved with minor structural modifications.

基于Motor-CAD的六相容错永磁同步电机仿真设计

为检验六相永磁同步电机的工作性能,对永磁同步电机的结构与特点进行分析,确定了其定转子内外径尺寸、气隙、槽型、轴向长度、极槽数等主要参数;基于Motor-CAD电机仿真软件,对六相容错永磁同步电机进行电磁计算,分析了不同齿宽、槽圆角半径、槽数、永磁体弧长下电机转矩脉动、齿槽转矩的变化,得到了转速为1500 r/min下的转矩脉动、齿槽转矩、电机最大可能转矩等电机性能指标,并采用螺旋水道水冷方式对电机进行冷却设计,求解出电机各部分的温度数据。通过仿真实验发现,设计的电机符合转矩和温度要求。

Dynamic analysis and optimization of car's body-in-white based on superelement approach

An approach based on the superelement theory is proposed, and it is applied to model the car's body-in-white as well as to dynamic simulation and optimization. This approach can improve the calculation speed and do the dynamic optimization among substructures respectively in the car's body design. To meet the car's design of harshness, a dynamic optimal design model, based on the mean square of vertical displacement response at two points of the car floor, is proposed. Satisfactory results are achieved.

离散元法软件与CAD软件集成开发研究

提出由机械部件的CAD模型(CAD设计图)建立其离散元法分析模型的方法,在此基础上实现了CAD软件与自主研制的离散元法分析软件集成,从而构建一种集设计和性能分析评价于一体的集成设计分析软件,为与散粒物料接触作用的相关机械部件的优化设计和虚拟设计提供了一种新方法和新工具。本文介绍了该集成设计分析软件的研究进展情况及下一步需解决的问题,并展望了应用前景。

基于CAD/CFD的方形锥管布浆器结构优化设计

针对方形锥管布浆器布浆不均匀的特性,提出一种基于CAD/CFD(计算机辅助设计和计算流体动力学)一体化的方锥形总管结构优化设计方法,以探寻方锥总管的合理结构形式。该方法整合了几何体设计、网格划分、数值求解过程,通过布浆支管束质量流量输出结果与设计目标的对比评价,依据流动中流体速度与压力之间所满足的伯努利方程关系,不断调整几何体的设计参数———方锥形布浆总管后壁高度hi(x),重复几何体设计、网格划分及数值计算过程,直至满足设计目标。结果表明,结构优化设计后总管的后壁形状是一条复杂曲线,在总管大端及回流端与简化型总管后壁相比有明显差别。总管内压力分布更为均匀,各支管对应位置的压力接近水平线型分布。支管束的质量流量分布与期望值线更为接近,质量流量偏差均小于1%。

钢筋混凝土框架结构优化CAD系统

针对传统钢筋砼框架结构ＣＡＤ系统没有考虑设计结果的经济性，将其与优化设计相结合，开发出了钢筋砼框架结构优化ＣＡＤ系统（ＦＯＣＡＤ系统）。从ＦＯＣＡＤ系统的构成与优化设计方法来看，与传统钢筋砼框架ＣＡＤ系统相比，ＦＯＣＡＤ系统既能满足结构设计规范要求，又能降低结构造价。

基于STEP的CAD/有限元/优化设计数据核

基于STEP/AP2 0 3、AP2 0 9、AR1 0 8、GR5 0和PLIB/GR2 0 ,构建了全面支持CAD设计、有限元分析和结构优化设计需求的CAD/有限元 /优化设计数据核。在该数据核基础上开发的有限元分析 /优化设计系统 ,可以直接利用三维CAD数据 ,进行有限元分析计算和结构优化设计计算。利用该数据核 。

建筑结构CAD课程教学改革研究

针对建筑结构CAD课程的教学现状,在分析和总结教学经验的基础上,从强化学生分析能力和优化设计能力、培养学生规范化和标准化意识、正确处理专业课的学习和PKPM软件应用的等方面进行了一系列改革。这些改革措施对于提高建筑CAD教学水平、培养学生的实际工作能力具有十分重要的意义。

从计算机辅助设计(CAD)到人辅助设计(HAD)--一种等几何拓扑优化方法

本文提出了一种新的设计模式——人辅助设计,以取代传统的计算机辅助设计。在人辅助设计中,计算机可以通过一种新的等几何拓扑优化自动完成整个产品设计,而人类仅需协助轻微修改设计以满足要求。文中提出了一种嵌入域等几何拓扑优化用于设计具有不规则设计域的复杂模型,并且可以基于分层等几何拓扑优化结果自动生成优化结果的可编辑几何模型。测试了三个算例以验证所提出的等几何拓扑优化模式,包括一个具有规则设计域的3D悬臂梁,一个具有不规则设计域的汽车零件和一个具有多尺度结构的MBB梁。结果表明,所提出的等几何拓扑优化模式可以自动生成高质量的优化模型。因此,该技术具有成为革命性技术的巨大潜力,将当前设计模式由计算机辅助设计转变为人辅助设计。

OCAD光学设计软件包

OCAD光学设计软件包是应用双优选阻尼最小二乘法为自动优化方法的多功能通用性光学设计CAD软件包,适用于IBM-PC/XT及其他兼容机。详细地介绍双优选阻尼最小二乘法的数学模型及自动优化方法,还介绍了软件包的基本功能及在软件包编制中几个具有特色的技巧和处理方法。

基于知识和CAD的结构设计自动化和优化系统分析

结构设计自动化可以加快结构设计 ,缩短结构设计周期。结构设计优化是根据价值工程原理 ,对众多结构设计方案进行成本估计 ,选择成本最低的方案。准确的成本估计不仅在结构设计优化中起着重要作用 ,而且在业主的项目决策和投资控制中起着重要作用。但是 ,由于设计阶段的时间限制 ,一般很少针对结构工程进行多方案的设计、成本估计和优化。本文探讨了基于知识和 CAD技术在结构设计自动化和优化方面的应用 ,建立了结构设计自动化和优化系统 ,该系统融合设计经验、成本信息和建筑规范 ,利用价值工程优化结构设计 ,自动生成成本报表和 CAD施工图。

基于广厦结构CAD和Matlab的剪力墙结构优化设计研究

本文以高层剪力墙为研究对象,进行地震作用下的力学性能模型分析研究。其间利用广厦结构CAD建立建筑结构计算模型,通过有限元分析技术进行相应的结构模型计算。同时,利用Matlab对结构模型进行优化设计,使各个构件之间的连接锚固更加稳固牢靠,荷载承载能力大大提高。

变结构变参数设计方法及其在机械CAD中的应用

提出了一种新颖的机械结构设计思想──变结构变参数设计方法，并结合实例，阐述了变结构变参数设计的概念、原则、实施措施和意义。由此对I-deas软件包进行了二次开发，编制了发动机曲轴专用CAD软件程序，并用某型号发动机曲轴进行了验证。

微波有源倍频器的设计与CAD优化技术

介绍了一种微波有源倍频器的设计方法。按照这种方法设计了一个X波段有源二倍频器,应用微波CAD软件进行了仿真与优化,并给出了仿真与实验的结果。实验结果表明,这种设计方法与过程在工程设计生产中是有效的。

大功率柴油机连杆CAD

本文针对铁道部资阳内燃机车工厂生产的16V240ZJ柴油机连杆多年来在实用中出现的裂损现象进行了研究,在IBM PC/XT微机上完成了有限元强度分析、大头斜切面角度的优化设计和自动绘制生产用的连杆零件图,且能运行于COMPAQ、AST、RUN等微机上,实现了较完整的CAD工作,并已应用到该厂实际生产中。

旋风分离器内置导流叶片结构参数优化研究

为研究旋风分离器内置导流叶片各个结构参数之间的相互作用,基于CFD数值模拟方法和BBD试验设计,采用二阶多项式基函数建立了Stairmand旋风分离器的叶片轴向位置、叶片长度及叶片偏转角度与分离效率及压降间的数学模型。拟合结果表明:响应目标的决定系数均在0.99以上,表明相关性和回归模型效果较好。使用Design Expert软件处理数据后选择了最佳推荐点,对分离器结构进行了优化。优化后的模型与原结构对比结果如下:优化模型的压降略有上升;颗粒直径在1~20μm范围内时,优化前后分离器的分离效率变化明显,尤其在1~15μm范围内时,优化前分离效率为6.8%~31.0%,优化后则达到了17.0%~54.0%,提升约20个百分点;而当粒径在15~40μm区间时,优化前后的分离效率变化不明显,尤其是在粒径20~40μm时,优化前的分离效率为71.0%~98.0%,而优化后的分离效率只有77%~99%,提升约10个百分点;优化后的模型性能符合“高效低阻”的设计目标。所得结论可为旋风分离器内置叶片的改进提供设计指导。