共查询到20条相似文献，搜索用时 93 毫秒
1.
To reduce the environmental impact of mechanical parts, an approach integrating structural design and material selection was studied. Adding the discrete variable of material, a hybrid optimization model was built with the aim of minimizing environmental impact and based on an ordinary structure optimization model. An optional material set was built by combining measures of qualitative and quantitative screening, while the lifecycle environmental impact of the materials was quantified using the method of Eco-indicator 99. Two groups of structurally optimal solutions were calculated with ideal and negative-ideal materials selected respectively, and then the hybrid model was simplified by comparing the solutions. A material environmental performance index was calculated using an analytic method. By comparing this index for every material in the optional material set, the optimal material can be found and the structural solutions calculated. This method was applied to a dowel bar design process as a case study. The results show that the environmental impact of each material has a significant effect on the optimal structural solution, and it is necessary to study the integration of structural design and material selection. 相似文献
2.
综合运用机械优化理论的优化设计方法,通过分析内燃机气门弹簧优化设计的设计变量、目标函数和约束条件,建立起以内燃机气门弹簧的质量、高度及防共振性能为目标函数的多目标优化设计数学模型,对多目标优化设计方法进行了探讨,并给出了设计实例.算例结果表明该方法具有工程实用价值. 相似文献
3.
水轮发电机组轴系的固有频率计算是振动研究的一个重要内容.针对三峡水轮发电机转子轴系,将其分解为数个单元,分别运用传递矩阵法和有限元法进行了编程计算,得到了其固有频率数值;随后分别研究了电磁刚度、附加水质量和陀螺效应对系统固有频率数值的影响规律. 相似文献
4.
赖章鹏黄卫东陈广宇洪浩张伟杰 《福建工程学院学报》2020,(1):23-28
横梁是数控玻璃加工机床关键零部件,利用ANSYS软件对其进行静、动态特性分析以及谐响应分析,获得了横梁极端工况的变形情况以及前六阶固有频率和振型,确认第2阶固有频率易引起横梁共振。以提高二阶固有频率为优化设计目标,横梁结构尺寸为优化变量,运用Isight软件及灵敏度分析方法对其进行优化。结果表明:优化后横梁质量减少了12.88kg,静变形量减少29.22kg,二阶固有频率增大13.34Hz。 相似文献
5.
蔡清波 《泉州师范学院学报》2011,29(2):43-45,64
研究Picard算子的逼近性质,利用Bojanic-Cheng-Khan的方法及Hldre不等式,运用分析技术和不等式技巧,得到了Picard算子对一类局部有界函数的渐近估计,并得出该算子的一个渐近展开公式. 相似文献
6.
ZHU Bin LEUNG A.Y.T. 《浙江大学学报(A卷英文版)》2006,7(8):1351-1357
INTRODUCTION Thin-walled structures have considerable tech-nological importance in many situations of engi-neering practice. The rotary and warping inertia terms should be considered in the analyses of thin-walled structures (Alwis and Wang, 1996), although it is difficult to obtain the analytical solutions of govern-ing differential equations, especially of thin-walled frame and spatial twisted structure. The finite element method (FEM) is widely used for vibration and sta-bility analy… 相似文献
7.
A multi-objective optimization of non-uniform beams is presented for minimum radiated sound power and weight. The transfer matrix method is used to compute the structural and acoustic responses of a non-uniform beam accurately and efficiently. The multi-objective particle swarm optimization technique is applied to search the Pareto optimal solutions that represent various compromises between weight and sound radiation. Several constraints are imposed, which substantially reduce the volume fraction of feasible solutions in the design space. Two non-uniform beams with different boundary conditions are studied to demonstrate the multi-objective optimal designs of the structure. 相似文献
8.
基于Gauss-Newton法的空间管形拟合算法的研究 总被引：1，自引：0，他引：1
三坐标测量仪在管类产品的加工验证中高频使用。在管形坐标的测量中,由于测量坐标系与设计测量系很难保持一致,通常需要将测量坐标在CAD软件中通过旋转、平移等操作与设计坐标进行吻合调整。但此操作依靠人眼进行吻合度判断,对比精度会大大降低,使三坐标测量仪的高精度得不到真正的发挥。本文在建立空间管形自由状态方程和两端约束管形方程的基础上,建立两种模型下的测量坐标管形与设计管形之间的最佳逼近目标方程,采用Gauss-Newton法对测量管形与设计管形进行最佳逼近求解,减少人为操作误差,提高测量精度。 相似文献
9.
基于Pareto遗传算法的多目标优化 总被引：3，自引：1，他引：2
张林家 《鞍山师范学院学报》2008,10(4)
在工程实际当中存在着大量的多目标优化问题,传统的多目标优化方法存在着明显的缺陷.本文介绍一种基于Pareto最优概念的遗传算法来求解多目标优化问题.这种方法能够给出多目标优化问题的Pareto解集,而不是单纯的一个解,从而可以帮助决策者在Pareto解集中挑选适合设计要求的解作为最终解. 相似文献
10.
Picard算子对绝对连续函数的逼近 总被引：1，自引：1，他引：0
蔡清波 《泉州师范学院学报》2010,28(6):63-65,69
研究Picard算子的逼近性质,通过直接计算得到Picard算子的一阶绝对矩Pn（｜t-x｜,x）的最优估计,由此估计结果,并结合Bojanic-Cheng-Khan的方法以及分析技巧,导出Picard算子对绝对连续函数的渐近估计,得出该算子的一个渐近展开公式. 相似文献
11.
针对一个Pareto局部搜索(PLS)算法在解决多目标组合优化问题中所得到的解集与初始点的选取有关,提出该算法的改进。改进算法从初始解开始进行PLS搜索产生一组改进解集VF,然后对VF中的所有解再进行PLS搜索,如此重复直到满足终止条件。实例计算表明,PLSⅠ算法和算法Ⅱ能得到很好的解且解的质量优于PLS算法。 相似文献
12.
We proposed an optimal design method to expand the bandwidth for the control of large hydraulic Stewart platform. The method is based on generalized natural frequency and takes hydraulic oil into consideration. A Lagrangian formulation which considers the whole leg inertia is presented to obtain the accurate equivalent mass matrix. Using the model, the effect of leg inertia and the influence of design parameters on the generalized natural frequency are investigated. Finally, numerical examples are presented to validate and confirm the efficiency of the mathematical model. The results show that the leg inertia, especially the piston part plays an important role in the dynamics. The optimum diameter ratio of the base to the moving platform is between 2 and 3, and the optimum joint angle ratio of the base to the moving platform is about 1. The smaller joint angles and a longer leg stroke are favorable for raising system frequencies. The system oil should be preprocessed for large platforms with a requirement for good dynamic performance. 相似文献
13.
研究了第二类Beta算子的逼近性质,通过直接计算得到第二类Beta算子Ln（t-x｜,z）的一阶绝对矩的最优估计,由此估计结果结合Bojanic-Cheng-Khan的方法以及分析技巧,导出第二类Beta算子对一类导数有界函数的渐近估计,得出该算子的一个渐近展开公式． 相似文献
14.
以机械传动系统中的斜齿轮啮合为研究对象,在考虑时变刚度、齿侧间隙和啮合误差的情况下,建立了十自由度斜齿轮非线性振动数学模型。以斜齿轮结构参数作为灵敏度分析参数,采用数值分析方法分别研究了斜齿轮系统振动加速度均方根值对齿轮质量、支撑刚度和支撑阻尼的灵敏度。结果表明:主、被动轮横向（y向）振动对各参数敏感度较低,横向振动（x向）与被动轮扭转振动对质量参数、刚度参数、阻尼参数较为敏感,被动轮扭转振动受到阻尼的影响很大,灵敏度在扭转振动固有频率处变化较大。 相似文献
15.
常姗 《渭南师范学院学报》2014,29(19):30-33
滨江道路是城市景观设计的重要内容,其对于城市文化建设有着重要意义．但目前城市滨江道路设计存在路面高程设定偏高、设计手法过于生硬、对城市休闲活动空间考虑不够充分等缺陷．为此。应从自然生态设计和人文生态设计两方面对城市滨江道路景观进行规划,从步行路线与速度、路面及人行道材质选择、亲水性等着手设计． 相似文献
16.
利用新方法—A-调和逼近技巧,研究Heisenberg群上非线性次椭圆方程组在自然增长条件下弱解的Hlder正则性,得到弱解的局部Γ1,α估计.该方法避免了反向Hlder不等式的建立和应用,且由此建立的Hlder指标是最优的. 相似文献
17.
This paper makes an approach to the approximate optimum in structural design, which combines the global response surface (GRS)
based multivariate adaptive regression splines (MARS) with Move-Limit strategy (MLS). MARS is an adaptive regression process,
which fits in with the multidimensional problems. It adopts a modified recursive partitioning strategy to simplify high-dimensional
problems into smaller highly accurate models. MLS for moving and resizing the search sub-regions is employed in the space
of design variables. The quality of the approximation functions and the convergence history of the optimization process are
reflected in MLS. The disadvantages of the conventional response surface method (RSM) have been avoided, specifically, highly
nonlinear high-dimensional problems. The GRS/MARS with MLS is applied to a high-dimensional test function and an engineering
problem to demonstrate its feasibility and convergence, and compared with quadratic response surface (QRS) models in terms
of computational efficiency and accuracy. 相似文献
18.
Jun-hai SHI Zhi-dan ZHONG Xin-jian ZHU Guang-yi CAO 《浙江大学学报(A卷英文版)》2008,9(3):401-409
This study presents a robust design method for autonomous photovoltaic （PV）-wind hybrid power systems to obtain an optimum system configuration insensitive to design variable variations. This issue has been formulated as a constraint multi-objective optimization problem, which is solved by a multi-objective genetic algorithm, NSGA-II. Monte Carlo Simulation （MCS） method, combined with Latin Hypercube Sampling （LHS）, is applied to evaluate the stochastic system performance. The potential of the proposed method has been demonstrated by a conceptual system design. A comparative study between the proposed robust method and the deterministic method presented in literature has been conducted, The results indicate that the proposed method can find a large mount of Pareto optimal system configurations with better compromising performance than the deterministic method. The trade-off information may be derived by a systematical comparison of these configurations, The proposed robust design method should be useful for hybrid power systems that require both optimality and robustness. 相似文献
19.
研究基于有限元模型的梁结构损伤识别的正反问题,即正问题采用有限元模型求解包含损伤位置和程度参数的结构前三阶固有频率,经曲面拟合技术拟合得到解曲面;反问题将实际损伤结构前三阶固有频率作为输入,绘制损伤梁结构位置和程度的等高线,根据曲线的交点识别出损伤梁结构损伤位置和程度。数值仿真算例表明:该方法具有足够的辨识精度,为梁类结构损伤识别提供了新方法。 相似文献
20.
为了减小数字滤波器设计工作量,利用MATLAB软件,采用窗函数法、频率采样法及最优等波纹法设计FIR数字滤波器.通过比较不同设计方法得到的滤波器阶数以及幅频特性曲线,结果表明,最优等波纹法可大大减少了计算的复杂程度,所设计的滤波器简单,是FIR滤波器设计中的最优方法. 相似文献