基于显著性分析的气缸盖结构优化设计

为了改变缸盖的结构,提高气缸盖运行工况下的温度分布及结构可靠性,进行了以鼻梁区宽度等六组参数为设计变量、以其许用范围约束条件、以等效热应力最低为优化目标的汽缸盖结构优化。基于正交实验法,构建了6因素5水平的正交实验表,并建立相应的三维模型,仿真得到了温度场及热应力。通过均值化法去量纲,分析得到了各因素的显著性水平,基于各因素的显著性水平选取了最优方案,并进行对比。结果表明,优化尺寸优选后方案的最大热应力比原始结构降低了13.48%,为缸盖的结构设计提供了一定的参考。     

2-RPU/SPR并联机构的多目标6Sigma稳健性优化

将Isight软件的NSGA-Ⅱ方法应用于2-RPU/SPR并联机构的6Sigma稳健性优化。方法建立2-RPU/SPR并联机构的工作空间、运动学灵巧度、刚度、最大和最小承载能力五个性能指标,设置约束条件,运用Matlab软件编程,并用Isight软件进行集成,进行确定性优化,得到优化解,在有噪声干扰的前提下,运用Isight对优化解进行6Sigma稳健性分析,进而运用NSGA-Ⅱ方法对这五个目标函数进行6Sigma稳健性优化。结果优化结果前后优劣对比,获得6Sigma稳健性优化后的良好结果。结论根据优化结果,并结合实际工况可选择最优设计参数,提高机构抗噪声干扰的能力,为高精密领域的包装机械提供一种高效直观的优化设计方法。     

龙门式多轴自动锁螺丝设备横梁结构优化

为实现龙门式多轴自动锁螺丝设备横梁的轻量化,结合BP神经网络与粒子群优化算法对其横梁进行结构优化。以横梁质量为目标函数,数个关键尺寸为设计变量,变形量及固有频率为约束条件建立数学模型。利用BP神经网络拟合设计变量与约束变量的映射关系,结合已建立的神经网络模型,应用基于Deb可行性规则改进的粒子群算法,在满足约束要求的条件下,寻求各关键尺寸的最优值。优化结果表明,优化后的横梁质量减少29.61%,实现横梁轻量化。     

柔性石墨纸轧机动刚度薄弱部位辨识与优化

借助谐响应分析辨识出柔性石墨纸轧机动刚度的薄弱环节,并利用灵敏度分析方法建立该环节的优化数学模型,进而实现对整机动刚度的提升。通过对各部件刚度提升前后的柔性石墨纸轧机进行模态分析,并对比各部件对整机固有频率的影响,辨识出薄弱部位为底座,故以底座为优化对象;将牌坊Y向共振频率对底座尺寸的灵敏度曲线拟合得出优化目标函数,以Y向共振频率为优化目标,质量为约束条件建立优化方程并求解;对比优化前后整机的动刚度,得出:在质量不增加的情况下,整机薄弱频率提升了24.1%,Y向振幅降低了15.9%。为提高优化效率提供了理论依据和参考。     

六角开槽螺母的冷镦工艺优化及数值模拟

传统的冷挤压工艺通常是根据经验反复的试模修模加以确定的,生产周期长,成本高。对六角开槽螺母进行了工艺分析,提出了两种不同的多工位冷镦工艺方案,并基于有限元技术DEFORM-3D分别对两种方案进行数值模拟仿真计算。分析比较了两种方案应力应变、载荷分布的规律。结果表明,采用第2种冷镦工艺方案时,各工位变形程度分配更为合理,模拟得到的零件表面质量更佳,模具使用寿命更长。将有限元技术应用于六角开槽螺母的工艺优化,对同类紧固件的成型工艺及模具设计具有一定的参考价值。     

喷涂机器人喷枪轨迹规划的优化算法研究

在建立了喷枪位姿模型和自由曲面上的涂层厚度数学模型后,提出了喷涂机器人喷枪轨迹规划的优化算法,并利用极大极小法进行求解.计算机仿真结果论证了本算法和数学模型的有效性,为离线编程系统的建立奠定了基础.     

数控车床嵌入式智能温度检测与实验

简要介绍了基于微控器ARM和单总线数字温度传感器DS18B20的嵌入式数控机床温度检测系统,该温度检测系统能实时、快速、精确检测数控机床不同部位的温度。重点介绍了嵌入式智能温度检测实验方案,以及利用分组优化理论处理实验数据,确定温度变量,从而优化模型结构。     

NUMERICAL SOLUTION OF FLUID-STRUCTURE INTERACTION IN LIQUID-FILLED PIPES BY METHOD OF CHARACTERISTICS

Fluid-structure interaction (FSI) is essentially a dynamic phenomenon and always exists in fluid-filled pipe system. The four-equation model, which has been proved to be effective to describe and predict the phenomenon of FSI due to friction coupling and Poisson coupling being taken into account, is utilized to describe the FSI of fluid-filled pipe system. Terse compatibility equations are educed by the method of characteristics (MOC) to describe the fluid-filled pipe system. To shorten computing time needed to get the solutions under the condition of keeping accuracy requirement, two steps are adopted, firstly the time step Δt and divided number of the straight pipe are optimized, sec-ondly the mesh spacing Δz close to boundary is subdivided in several submeshes automatically ac-cording to the speed gradient of fluid. The mathematical model and arithmetic are validated by com-parisons between simulation solutions of two straight pipe systems and experiment known from lit-erature.     

MODIFIED GENETIC ALGORITHM APPLIED TO SOLVE PRODUCT FAMILY OPTIMIZATION PROBLEM

The product family design problem solved by evolutionary algorithms is discussed.A successful product family design method should achieve an optimal tradeoff among a set of compet- ing objectives,which involves maximizing commonality across the family of products and optimizing the performances of each product in the family.A 2-level chromosome structured genetic algorithm (2LCGA)is proposed to solve this class of problems and its performance is analyzed in comparing its results with those obtained with other methods.By interpreting the chromosome as a 2-level linear structure,the variable commonality genetic algorithm(GA)is constructed to vary the amount of plat- form commonality and automatically searches across varying levels of commonality for the platform while trying to resolve the tradeoff between commonality and individual product performance within the product family during optimization process.By incorporating a commonality assessing index to the problem formulation,the 2LCGA optimize the product platform and its corresponding family of products in a single stage,which can yield improvements in the overall performance of the product family compared with two-stage approaches(the first stage involves determining the best settings for the platform variables and values of unique variables are found for each product in the second stage). The scope of the algorithm is also expanded by introducing a classification mechanism to allow mul- tiple platforms to be considered during product family optimization,offering opportunities for supe- rior overall design by more efficacious tradeoffs between commonality and performance.The effec- tiveness of 2LCGA is demonstrated through the design of a family of universal electric motors and comparison against previous results.     

钢丝绳牵引皮带机差动器模糊可靠性优化设计

以装载机差速器的锥齿轮端面模数、锥齿轮齿数、齿宽系数为设计变量,以差速器体积最小为目标函数,考虑锥齿轮弯曲强度可靠度、孔径条件、装配条件、边界条件,基于模糊设计理论、可靠性设计理论,对差速器进行优化设计.