基于模拟试验法的离散公差稳健设计

 在分析计算机辅助公差设计技术的研究现状的基础上，提出了基于模拟试验法的离散公差稳健设计方法．在该方法中将加工成本与质量损失作为两个独立的目标函数，从而建立离散公差优化设计模型，采用试验设计法和CP方法相结合的技术实现公差的稳健设计，最后用实例证明该方法的可行性．     

基于模糊神经网络的公差-成本模型研究

研究了面向制造环境的公差-成本模型。对制造环境中有关的加工因素进行分类及模糊化处理,构造了加工因素的成本模糊影响系数,并以此系数和零件公差作为输入,建立了基于模糊神经网络的公差-成本模型。此模型在表征加工成本、公差关系上的精度较高,更适应面向制造公差设计的要求。     

基于双响应面法的公差设计研究

探讨了产品综合成本的构成,以此为基础提出了以产品综合成本最低为目标的公差稳健设计模型,并利用双响应面法(Response Surface Methodology ,RSM) 来实现公差的稳健优化设计。     

基于加工特征的成本—公差模型研究

按机械零件的加工特征－外圆特征、孔特征、平面特征、定位特征对零件尺寸进行分类提出适用于我国中型企业的各分类尺寸的加工成本－公差模型。     

公差理论的成就与动向

本文对目前出现的漂移公差带理论、矢量法进行介绍和分析,指出公差理论发展的总动向是基于数学的公差定义,这为CAD、CMM、CNC的广泛应用奠定了基础。     

尺寸公差与形位公差优化设计的模型研究

在分析计算机辅助公差设计现状的基础上,引入不匹配率,研究尺寸公差与形位公差在产品性能要求上的互相约束关系,从而提出包括尺寸公差和形位公差的综合公差优化设计模型。     

汽车车身耐撞性设计参数的区间稳健性优化

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。     

ISO 8015产品几何技术规范公差原则研究

规范的图纸标注与正确的图纸理解对设计、生产、检测都有重要的意义,文章以ISO 8015及GB/T 4249为研究对象,结合相关实例介绍了产品几何技术规范的公差原则部分,其中包括独立原则、尺寸公差(线性尺寸公差和角度尺寸公差),以及尺寸公差和几何公差互相关联的公差要求。     

航空发动机装配尺寸链公差设计方法研究

介绍了航空发动机装配尺寸链的概念以及封闭环的特征,详细分析了3种适用于航空发动机的典型公差设计分析方法.通过几种典型的航空发动机装配精度要求算例,研究了公差设计分析方法的特点,并结合航空发动机结构和装配特点,提出了3种公差设计分析方法在航空发动机领域的适用性,以及对发动机公差设计运用的展望.     

A proposal of cost-tolerance models directly collected from the manufacturing process

In this paper, the concept of cost-tolerance functions based on data directly obtained from the manufacturing process is proposed. Traditional models used in manufacturing field define cost-tolerance relationships from mathematical functions whose relationship with the process is not usually set in a clear way. In this work, proposed models allow to obtain cost-tolerance functions directly from parameters measured on manufacturing process. The paper defines some of these functions using statistical distributions derived from the population of manufactured parts. A general methodology to reach a cost-tolerance function from any distribution of the manufactured parts is proposed. Once functions are defined, an application example is presented. Finally, the main criteria for suitable appropriateness use of models are established.     

Economic tolerance design for quality

This paper provides a few general mathematical models for determining product tolerances which minimize the combined manufacturing costs and quality loss. The models contain quality cost with a quadratic loss function and represent manufacturing costs with geometrical decay functions. The models are also formulated with multiple variables which represent the set of characteristics in a part. Applications of these models include minimizing the total cost with effective tolerance allocation in product design.     

An Affordable Approach for Robust Design of Thick Laminated Composite Structure

A systematic and affordable approach is proposed for the robust design of thick laminated composite structures. Our approach integrates the principles of the Robust Concept Exploration Method (RCEM) for designing complex engineering systems and the hierarchical multi-level optimization procedure for managing the complexity of composite structure optimization. Foundational to the proposed approach is the use of Design of Experiments (DOE) techniques and the Response Surface Methodology (RSM) for improving computational efficiency in using high fidelity design simulations; and the use of the robust design method for improving the quality of a product that is insensitive to potential variations of design parameters. Our approach is illustrated through the design of a laminated composite femoral component for hip joint arthroplasty. The solution yields the robust design of a composite hip implant, which is applicable for a range of bone stiffness, thereby eliminating the need to design specifically for an individual.     

多失效模式机械系统可靠性稳健设计方法研究

将机械系统可靠性设计理论和稳健设计方法相结合,讨论了多失效模式机械系统可靠性稳健设计问题,提出了多失效模式机械系统可靠性稳健设计的计算方法．把可靠性灵敏度融入可靠性优化设计模型之中,将机械系统可靠性稳健设计归结为满足可靠性要求的多目标优化问题．在基本随机参数的前二阶矩已知的情况下,可以迅速准确地得到机械系统可靠性稳健设计信息．     

微机械陀螺结构的稳健优化设计

本文提出一种基于容差分析的微机械陀螺稳健设计方法,开发了相应的稳健优化设计流程.该方法采用估算目标函数和约束的名义值与扰动值来定义系统稳健性,同时将最坏情况容差作为设计参数的扰动.在集成了器件建模和优化工具的设计环境中开发了相应的自动化设计流程,可用于微机械陀螺的结构设计.优化算法使用遗传算法.讨论了不同的稳健设计方法,结果表明本文的方法能以合适的计算成本获得高质量的结果.系统敏感性分析表明,稳健优化设计结果对误差是不敏感的.采用蒙特卡洛分析检验稳健设计的产出率,结果表明有88%的试验样本是可接受的,而对于确定性优化,仅有50%的可接受样本.微结构已经采用键合-深反应离子刻蚀工艺加工出来.     

Optimal process capability analysis for process design

Conventional process capability analysis is used to measure and control the quality level of a production process in real exercises for on-line quality management. There has been a deficiency in this type of management; namely, the defects which occur in the production process are only passively detected and modified afterwards. Additionally, conventional process capability expression has difficulty distinguishing between alternatives for process selection among possible candidates before process realisation. There is, therefore, considerable motivation for developing a process capability expression which can be used to evaluate alternatives at the beginning of the process design, i.e., off-line application. The conventional C_pm expression is built up by measuring mean deviation and process variances for on-line application. However, if C_pm is used for the process capability analysis for process design, an erroneous C_pm value is found and an inappropriate process design is ended. Thus, the proposed process capability expression revised from the conventional C_pm in consideration of the balance between tolerance cost and quality loss has been developed. This development is the main contribution of this research and, with this development, the appropriate mean and tolerance values can be determined simultaneously prior to the real production process so as to maximise the proposed process capability value. The production is then processed with the pre-determined mean and tolerance values in a real production process. The expectation after process realisation is that the produced responses will be the best of all the alternatives in terms of quality and cost, and that the process capability value obtained after the real production process will be close to the proposed process capability value maximised prior to the real production process.     

Modified robust geotechnical design approach based on the sensitivity of reliability index

The robust geotechnical design (RGD), which aims to ensure a design that is robust against variations in the input variables, is receiving wider attention and acceptance in the past few years. In this paper, the authors proposed the sensitivity of reliability index (SRI) to evaluate the feasibility robustness of the design, resulting in a modified RGD approach. The performance of the proposed approach was examined by a geotechnical design example, and its advantages are evidenced.     

An information management paradigm for statistical experiments

Optimization of engineering processes and products via statistical design of experiments is an approach well known to statisticians but still not popularly used by technical personnel. This paper sets out a pattern of reasoning that would facilitate the appreciation, on the part of non‐mathematicians, of the principles and advantages of using statistical experimental design for process and product modeling and optimization. Use is made of the concepts of information transformation and conservation in a language that is familiar to those of purely technical background, leading to better understanding, acceptance and application of the efficiency and effectiveness of statistical experiments. In today's environment of the prevalence of software and hardware for statistical analysis, engineers concerned with quality and reliability would particularly benefit from such a paradigm for process and product performance improvement. Copyright © 2009 John Wiley & Sons, Ltd.     

Principles of robust design methodology

The literature on robust design has focused chiefly on the development of methods for identifying robust design solutions. In this paper we present a literature review of conflicts and agreements on the principles of robust design. Through this review four central principles of robust design are identified: awareness of variation, insensitivity to noise factors, application of various methods, and application in all stages of a design process. These principles are comprised into the following definition of robust design methodology: Robust design methodology means systematic efforts to achieve insensitivity to noise factors. These efforts are founded on an awareness of variation and can be applied in all stages of product design. Copyright © 2007 John Wiley & Sons, Ltd.