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提出包装缓冲垫层优化设计的半可变容差法。该法吸取了数学规划问题中可行方向法与可变容差法的优点,通过具体结构的计算,对三种优化设计方法进行了比较。结果表明,半可变容差法的优化结果可以为包装设计作出预先评价与论证。 相似文献
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承受随机振动环境的装备,一般采用功率谱密度作为振动环境条件。对于各频点幅值满足正态分布的实测功率谱密度,常采用正态单边容差上限方法进行统计归纳形成试验谱。为确定上限估计误差与样本量的关系,结合正态单边容差上限的定义,推导了正态单边容差上限估计的均方根误差和百分比误差的公式,并结合数值仿真校验了此函数关系的正确性,同时结合工程实际对公式合理简化,得到上限估计误差的最大值与样本量的函数关系式,并给出了控制上限估计误差所需的最大样本个数。对比了不同样本量下自助容差上限和正态单边容差上限误差,结果表明:至少需要20个样本才能使得P95/50上限估计误差不超过10%;至少需要54个样本才能使得P99/90上限估计误差不超过10%;自助容差上限方法在小样本统计归纳时有一定优势。 相似文献
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本文提出一种有效提高真空封装硅微陀螺机械稳定性的方法.通过谐振增益与模态频差的参数灵敏度关系可知,随着模态频差的增大,机械谐振增益对模态频差的灵敏度减小,外界环境引起的模态频差的微弱抖动量决定驱动、敏感模态频率差的设计极大值,因此当频差设计值的变化量等于外界引起的频差抖动量且谐振增益满足应用需求时,真空封装硅微陀螺的机械稳定性达到最优.仿真结果表明机械稳定性提高12.7%,最佳封装气压约为5.3kPa.实测结果表明,零漂提高到0.9mV时,刻度因子的线性度为700×10^-6,带宽提高3倍,约为89Hz.该方法为真空封装硅微陀螺仪的参数优化提供了理论依据. 相似文献
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微机电系统(MEMS)是一个新兴的跨学科研究领域,成本和可靠性是MEMS商品化的关键。与传统的机械加工和IC加工相比,MEMS加工的尺寸偏差比较大,而且很难控制,因此需要在设计过程中充分考虑加工的不确定性。稳健设计可以在不提高制造成本的前提下提高设计方案的稳健性。稳健优化设计方法主要包括 Taguchi方法和基于容差模型的方法,后者特别适合于处理带约束的优化设计问题。以微加速度计和微阀为例给出了稳健设计在MEMS设计中的应用,验证了稳健设计可以显著提高MEMS器件的信噪比。 相似文献
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导管架海洋平台结构模糊优化设计 总被引:7,自引:0,他引:7
考虑约束条件边界的模糊性,建立了导管架海洋平台结构模糊优化设计模型。对模糊优化模型中的设计变量、目标函数和约束条件进行了模糊处理。针对导管架海洋平台的特点,用模糊优选法确定约束条件边界容差系数,由界限搜索法求解模糊约束集和模糊目标集之交集的最优水平截集*l,进而求得模糊优化问题的最优解。以胜利油田埕北11#井采油平台为例进行了模糊优化设计,并与确定性优化设计相比较,分析了两种优化设计中设计变量的走向及原因,算例结果还显示目标函数值比确定性优化设计值有较大幅度下降,说明考虑模糊因素进行优化设计的可行性和科学性。 相似文献
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一种电磁式微机械振动环陀螺的建模与优化 总被引:5,自引:2,他引:3
提出了一种新型的电磁式微机械振动环陀螺结构.为优化陀螺的设计和提高陀螺的性能,在推导微机械陀螺集总参数模型的基础上,建立了电磁式微机械振动环陀螺的数学模型,得到了影响陀螺灵敏度的因素,据此对陀螺参数进行优化设计.采用有限元分析方法和实验测试方法相结合来验证该模型和设计方案的可行性.模型计算结果表明,优化后的陀螺在-200~200(°).s^-1的范围内,其机械灵敏度为0.002 3μm/((°).s^-1),电学灵敏度为0.062μV/((°).s^-1).用有限元模拟得到陀螺机械灵敏度为0.002 9μm/((°).s^-1),锁相放大器测试得到微陀螺样机电学灵敏度为0.051μV/((°).s^-1).有限元仿真和样机实测结果与理论计算结果基本吻合,证实了该模型的正确性及陀螺设计方案的可行性. 相似文献
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Sangmun Shin 《工程优选》2013,45(11):989-1009
Many practitioners and researchers have implemented robust design and tolerance design as quality improvement and process optimization tools for more than two decades. Robust design is an enhanced process/product design methodology for determining the best settings of control factors while minimizing process bias and variability. Tolerance design is aimed at determining the best tolerance limits for minimizing the total cost incurred by both the customer and manufacturer by balancing quality loss due to variations in product performance and the cost of controlling these variations. Although robust design and tolerance design have received much attention from researchers and practitioners, there is ample room for improvement. First, most researchers consider robust design and tolerance design as separate research fields. Second, most research work is based on a single quality characteristic. The primary goal of this paper is to integrate a sequential robust design–tolerance design optimization procedure within a bi-objective paradigm, which, the authors believe, is the first attempt in the robust design and tolerance design literature. Models are proposed and numerical examples along with sensitivity analysis are performed for verification purposes. 相似文献
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Tolerance directly influences the functionality of the products and the related manufacturing costs, and tolerance allocation is of great importance for improving the assembly quality. However, the information required to allocate tolerances for complex 3D assemblies is generally not available at the initial design stage. In this paper, a new quality design methodology is developed, which makes use of both original design data obtained by the response surface methodology and the extra interpolation data obtained by the Kriging method. The finite element modelling is presented for the sheet metal assembly process as no explicit relationship of the variations for key characteristic points are available. The robust tolerances can be allocated based on the quality design model. A case study with the typical assembly process of the rear compartment pan and the wheelhouse is carried out in the paper, the tolerance allocation results show that the developed quality design methodology is capable of determining the robust manufacturing tolerance before assembly, which satisfies the product requirements. This method enables a robust tolerancing scheme to be used in the sheet metal assembly process. 相似文献
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Abstract Tolerance allocation in manufacturing is a prominent industrial task for enhancing productivity and reducing manufacturing costs. The classical tolerance allocation problem can be formulated as a stochastic program to determine the assignment of component tolerances such that the manufacturing cost is minimized. However, tolerance design is a prerequisite to the overall quality and cost of a product; robust tolerance design is particularly important and should be considered. In this paper, robustness is considered in formulating the tolerance allocation problem by minimizing the manufacturing cost's sensitivity. Moreover, from a practical perspective, the process capability index for each component and the upper bound of the manufacturing cost are also considered. To effectively and efficiently resolve the robust tolerance allocation problem, a sequential quadratic programming algorithm embedded with a Monte Carlo simulation is developed. To demonstrate this design method's robustness, two commonly used test problems are solved. The designs devised in this paper have lower manufacturing costs and smaller variations in manufacturing costs than those in previous studies, indicating that the proposed method is highly promising in the robust tolerance design. 相似文献
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Compromise Decision Support Problems (DSPs) are used to model engineering decisions involving multiple trade-offs. In this paper, the focus is on how to apply such decision models in robust design. Suh's independence and information content axioms and Taguchi's signal to noise ratio are used as metrics for the assessment and improvement of the quality in this decision model. As an example, a compromise DSP for the robust design of an electrical network is used. Traditionally, in robust design, parameter and tolerance design are done sequentially and not concurrently. Furthermore, each time parameter and tolerance design are done in practice, the focus is usually on looking at one parameter at a time and not on looking at multiple parameters simultaneously. Using the electrical network as an example, it is shown how parameter and tolerance design involving multiple parameters can be performed concurrently. 相似文献
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This paper presents a design method for allocating dimensional tolerances of products with asymmetric quality losses. The design strategies proposed include the adjustment of manufacturing target and the approach of robust tolerance design. The average quality losses of batch products are computed differently in accordance with the distribution of functional characteristics. The robust tolerance design is based on the balance between manufacture cost and quality loss expected. An illustrative example shows the proposed procedure for the tolerance design of a helical spring. 相似文献
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建立了微陀螺的动力学模型,采用多尺度方法对微陀螺的非线性模型进行求解,探讨了驱动微弹性梁和检测微弹性梁的非线性刚度对微陀螺输出的影响规律,研究了微陀螺的带宽在非线性刚度作用下的设计原则,结果表明:微陀螺振动系统的检测灵敏度和带宽呈反比关系;微弹性梁的非线性刚度会使得输入角速度与检测输出呈非线性关系。因此,从微弹性梁的设计角度出发,可根据较大的输出或者较小的非线性要求选取合适的驱动微弹性梁;而检测微弹性梁则需要选取较小的非线性刚度。 相似文献
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Optimal robust and tolerance design for computer experiments with mixture proportion inputs 下载免费PDF全文
Mei Han Matthias Hwai Yong Tan 《Quality and Reliability Engineering International》2017,33(8):2255-2267
Computer experiments often have inputs that are proportions/fractions of components in a mixture. In these mixture computer experiments, it can be of interest to perform robust and tolerance design on the mixture proportions since the proportions are subjected to noise variations. Traditionally, manufacturing of mixture products is controlled via interval tolerances for mixture amounts. In this paper, an optimal tolerance region for proportions, which gives optimal quality cost among all possible tolerance regions for mixture proportions with the same acceptance probability, is proposed for integrated parameter and tolerance design in mixture computer experiments. Real examples are given to demonstrate the improvements that can be achieved with the optimal tolerance region. 相似文献
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基于区间分析,提出了一种考虑公差的汽车车身耐撞性稳健优化设计模型,可在有效降低耐撞性能对设计参数波动敏感性的同时实现公差范围的最大化。该模型首先利用对称公差来描述汽车碰撞模型中车身关键耐撞部件的主要尺寸、位置和形状等设计参数本身的不确定性,然后将参数设计和公差设计相结合,建立了以稳健性评价指标和公差评价指标为优化目标,设计变量名义值和公差同步优化的多目标优化模型。再次,利用区间可能度处理不确定约束,将该优化模型转换为确定性多目标优化模型。最后,将该模型应用于两个汽车耐撞性优化设计问题,并通过序列二次规划法和改进的非支配排序遗传算法进行求解,结果表明该方法及稳健优化设计模型可行且实用。 相似文献