基于图论方法与优化算法的六折痕折纸结构构型研究

近年来,折纸结构快速发展并成功应用于诸多领域,但仍存在折纸新构型难以构建、构型与折展运动难以协调等难题。为了研发多折痕折纸结构,本文考虑折纸构型的规整性及可折叠性,基于图论方法描述折纸折痕构型,并建立折纸顶点的几何约束方程组,综合采用图解法及优化方法,求解单元内部可平折点,得到一系列基于不同对称单元的六折痕折纸结构构型。该折痕设计方法适用于任意边界条件的六折痕折纸结构,可为折纸结构创新与应用发挥积极作用。     

基于Yoshimura折纸模式的可展结构参数化设计

刚性折纸在折叠过程中可以保证折痕之间的面不会发生弯曲和拉压等其他形变,因此越来越多地被用于实际工程结构中.本文将Yoshimura折纸模式用于建筑结构设计中,研究一种可在平面进行板件连接,通过折叠能够形成立体结构的可展式建筑.首先利用雅克比矩阵法对Yoshimura折纸模式的基本单元进行自由度分析,得到了目标结构所需的运动轨迹;分析结构展开时的平面角和折叠后的二面角之间的关系,得到了两者之间相互影响的3个规律,并利用平面角、二面角、谷折数和单元长度各个参数建立了结构尺寸的计算公式;最后提出了增加结构高度的两种拓展模式：四边形增高和三角形增高,通过比较结构整体变形情况和破坏类型,最终选择三角形增高方案来实现结构高度的增加.通过以上研究,可以对基于Yoshimura折纸模式的可展建筑结构进行初步设计.     

基于改进人工鱼群算法的空间桁架结构优化研究

以工程应用为目标,针对基本人工鱼群算法在优化过程中存在的很多不足,对人工鱼的搜索视野和移动步长进行了改进,提出了一种改进的自适应人工鱼群算法,并结合对一个25杆空间桁架结构进行形状优化设计,比较详细的介绍了运用该方法进行优化的思想和策略,表明了改进的鱼群算法的可行性。     

基于粒子群算法的桁架结构优化

粒子群算法(PSO)是一种基于种群智能的优化算法。由于其具有快速收敛和操作简单等特点,粒子群算法在工程、经济管理等诸多领域均得到广泛应用,成为近年来智能计算领域研究的新热点。首先介绍粒子群算法,进而提出对于惯性权重进行线性变化。利用改进的粒子群算法对实际工程桁架结构进行尺寸优化以提高经济效益,并提出合理的参数设置。数据对比分析结果表明,改进的粒子群算法对于桁架结构尺寸优化设计是可行的。     

基于Q学习蚁群算法的热网优化方法

以热网最小年费用作为目标函数,引入基于Q学习规则的蚁群算法,建立了热网优化算法。结合算例,比较了比摩阻算法、模拟退火算法、基于Q学习规则蚁群算法,基于Q学习规则蚁群算法的热网最小年费用最低。     

浅谈结构优化设计中的蚁群算法

结构优化设计是设计理论的重要方面,在建筑界得到广泛的重视,随着社会经济的发展,结构设计也得到了长足的发展,对于结构优化设计理念和算法,人们也提出了越来越高的要求。随之蚁群算法逐步得到了发展,蚁群算发是一种新型的、新生的仿生进化算法。有着很强的适应性。也比较容易和其他的方法结合来运作,所以,研究蚁群算的优化方法,有着十分重要的意义,本文将会总结蚁群算法的原理,以便能够在现实中能够广泛的运用。     

基于混合遗传算法的结构优化设计

针对遗传算法在迭代过程中经常出现早熟、收敛速度慢、局部搜索能力差等缺点,对遗传算法中的遗传算子进行了改进,提出梯度算法与遗传算法相结合的混合遗传算法。分析表明,这种混合遗传算法既发挥了梯度算法局部搜索能力强的特点,又结合了遗传算法全局搜索能力强的优点,避免出现早熟现象,使收敛速度大大改善,具体算例表明该混合遗传算法是一种有效的工程结构优化方法。     

现代智能优化算法研究综述

主要介绍了现代智能优化算法的基本概念,着重回顾了几种主要的现代智能算法的发展历程,主要包括遗传算法、神经网络优化算法、粒子群优化算法、模拟退火算法,并阐述了其工作原理和特点,归纳了它们主要的应用方向,同时对智能计算方法的发展进行了展望。     

可展折纸结构国际工作坊的实践与思考

随着高等学校国际合作交流机会的增多,工作坊作为一种新的教学模式,其应用越来越广泛。以丹麦皇家艺术学院举办的"可展折纸结构在工程中的应用"国际工作坊为例,对工作坊的各个环节进行详细的介绍,包含前期计划、学术汇报、指导教师演示、学生确定研究主题、模型制作及各组的成果答辩等。此外,分析了联合工作坊在促进学生跨学科思维的碰撞与交流,培养学生团队精神和沟通能力,促进教学与实践相互统一等方面的意义,并对工作坊在土木工程学科的适用性进行了探究。     

基于进化算法的金属烤瓷全冠结构优化

基于进化算法对多工况作用下的金属烤瓷全冠进行了优化设计,针对金属烤瓷全冠的临床应用和加工工艺特性,在优化设计过程中,以前牙面积最小为目标函数,以离散变量的形式描述由金属基底厚度、遮色瓷厚度、体瓷平均厚度构成的设计变量,计算表明初始设计方案中的厚度尺寸留有很大裕度,研究结果可为今后金属烤瓷全冠的优化设计提供临床参考。     

Research on origami patterns for six-fold origami structures using graph theory and optimization algorithms

近年来，折纸结构快速发展并成功应用于诸多领域，但其仍存在折纸新构型难以构建、构型与折展运动难以协调等难题。为了研发多折痕折纸结构，考虑折纸构型的规整性及可折叠性，基于图论方法描述折纸折痕构型，建立折纸顶点的几何约束方程组，综合采用图解法及优化方法，求解单元内部可平折点，得到一系列基于不同对称单元的六折痕折纸结构构型。研究表明，该折痕设计方法精确可行，且具有并行性，能求得给定单元形状的所有内部可平折点。该折痕设计方法适用于任意边界条件的六折痕折纸结构，可为折纸结构创新与应用发挥积极作用。     

Comparative seismic design optimization of spatial steel dome structures through three recent metaheuristic algorithms

Steel dome structures, with their striking structural forms, take a place among the impressive and aesthetic load bearing systems featuring large internal spaces without internal columns. In this paper, the seismic design optimization of spatial steel dome structures is achieved through three recent metaheuristic algorithms that are water strider (WS), grey wolf (GW), and brain storm optimization (BSO). The structural elements of the domes are treated as design variables collected in member groups. The structural stress and stability limitations are enforced by ASD-AISC provisions. Also, the displacement restrictions are considered in design procedure. The metaheuristic algorithms are encoded in MATLAB interacting with SAP2000 for gathering structural reactions through open application programming interface (OAPI). The optimum spatial steel dome designs achieved by proposed WS, GW, and BSO algorithms are compared with respect to solution accuracy, convergence rates, and reliability, utilizing three real-size design examples for considering both the previously reported optimum design results obtained by classical metaheuristic algorithms and a gradient descent-based hyperband optimization (HBO) algorithm.     

基于群论的闭合环形过约束体系可动性研究

Bennett单元及Bricard单元等典型闭合环形机构具有可动自由度,可在无应变状态下产生连续、较为显著的几何构型变换,已广泛应用于可展结构工程中。基于此,建立了由闭合环形的刚性折杆组成,可进行旋转、镜像等对称操作,且在运动过程中始终保持一定对称性的过约束机构。任一折杆的两端通过扭转副单元分别连接至其它2根折杆,且扭转副单元的可转动方向与杆轴线重合。在刚性折杆单元平衡矩阵的基础上,建立结构的整体力平衡矩阵,从矩阵的左零空间、零空间分别求得结构的机构位移模态及自应力模态。引入群论方法预测机构位移模态的对称性,并对结构的可动性进行分析。为了验证该类对称体系的可动性,采用基于牛顿迭代技术的非线性预测 修正算法,对结构进行完整路径的运动模拟。针对2个不同对称性的六杆过约束机构算例进行对称分析及运动模拟,结果表明：算例所述的2个对称过约束体系均为单自由度可动结构,可作为可展结构推广应用。     

A comparison of global optimization algorithms with standard benchmark functions and real-world applications using EnergyPlus

There is an increasing interest in the use of computer algorithms to identify combinations of parameters that optimize the energy performance of buildings. For such problems, the objective function can be multi-modal and needs to be approximated numerically using building energy simulation programs. As these programs contain iterative solution algorithms, they introduce discontinuities in the numerical approximation to the objective function. Metaheuristics often work well for such problems, but their convergence to a global optimum cannot be established formally. Moreover, different algorithms tend to be suited to particular classes of optimization problems.

To shed light on this issue, we compared the performance of two metaheuristics, the hybrid CMA-ES/HDE and the hybrid PSO/HJ, in minimising standard benchmark functions and real-world building energy optimization problems of varying complexity. From this, we find that the CMA-ES/HDE performs well on more complex objective functions, but that the PSO/HJ more consistently identifies the global minimum for simpler objective functions. Both identified similar values in the objective functions arising from energy simulations, but with different combinations of model parameters. This may suggest that the objective function is multi-modal. The algorithms also correctly identified some non-intuitive parameter combinations that were caused by a simplified control sequence of the building energy system that does not represent actual practice, further reinforcing their utility.     

Design optimization of 3D steel structures: Genetic algorithms vs. classical techniques

In this paper an elitist genetic algorithm (GA) developed by the authors is compared with common commercial solutions for complex structural optimization. After its prior validation on two-dimensional (2D) structures, the GA was tuned and improved in order to obtain structural elements with minimum weights that satisfy the ultimate limit states of the applicable building code. Subsequently, the same spatial structures were optimized using a commercial structural analysis program. Finally, the cost and weight improvements obtained using the GA, although at a higher computational cost, are discussed.     

Practical optimization of deployable and scissor-like structures using a fast GA method

This paper addresses practical sizing optimization of deployable and scissor-like structures from a new point of view. These structures have been recently highly regarded for beauty, lightweight, determine behavior, proper performance against lateral loads and the ability of been compactly packaged. At this time, there is a few studies done considering practical optimization of these structures. Loading considered here includes wind and gravity loads. In foldable scissor-like structures, connections have a complex behavior. For this reason, in this study, the authors used the ABAQUS commercial package as an analyzer in the optimization procedure. This made the obtained optimal solutions highly reliable from the point of view of applicability and construction requirements. Also, to do optimization task, a fast genetic algorithm method, which has been recently introduced by authors, was utilized. Optimization results show that despite less weight for aluminum models than steel models, aluminum deployable structures are not affordable because they need more material than steel structures and cause more environmental damage.     

不同优化算法在工程实际中的主要特点及优势

算法取代工程师的人工调试工作一直是一个比较热门的结构设计研究方向,但未大量应用于工程实际。主要介绍了实际工程中,利用结构设计行业内出现的新变量,如更高效的优化算法、编程能力在新一代结构设计从业人员中的普及、国内一线设计软件逐步开放程序控制接口等,针对不同工程实际问题采用不同算法进行设计的实际案例;并介绍了采用算法设计的优势,如在超高层设计中采用了响应面算法优化型钢用量,在大跨度天幕设计中采用模拟退火算法进行曲线找形,在桩基设计中通过对桩布置进行参数化快速设计更新。通过这些案例笔者认为结构设计行业推广算法设计的条件已基本具备。     

基于遗传算法的飞艇结构多目标优化

首先,根据软式飞艇结构的力学特点建立了飞艇结构的多目标优化模型,以外荷载作用下飞艇“应力最小”、“变形最小”及“自重最小”为优化目标,确定膜材厚度、膜材弹性模量、飞艇内气压及飞艇细长比为优化变量.其次通过加权系数法将多目标优化转化为单目标问题,并采用遗传算法进行求解.最后,采用此方法对某一飞艇结构进行多目标优化.研究结果表明：飞艇的优化模型是有效的;结合加权系数法和遗传算法,可以获得各个目标均较理想的优化结果;通过进行多目标优化可以为飞艇结构的设计提供合理建议.     

Structural optimization of jacket supporting structures for offshore wind turbines using colliding bodies optimization algorithm

Considering the size and dimension of offshore wind turbine structures, structural optimization of such structures, notwithstanding being outstandingly fruitful, is a tedious task. Nonetheless, in this paper, a metaheuristic algorithm named as colliding bodies optimization is employed when investigating the optimal design of jacket supporting structures for offshore wind turbines. The OC4 reference jacket is considered as the case study, validating the outcomes of this research. To do so, MATLAB is utilized in modeling the structure. The structural optimization is then performed when both ultimate limit state and frequency constraints are being considered. During the optimization process, the weight of the structure is approximately halved, and its first and second frequencies are kept within the considered soft–stiff range (0.21–0.32 Hz).