非正态分布参数的车辆零件可靠性稳健设计

将可靠性优化设计理论、可靠性灵敏度技术与稳健设计方法相结合,讨论了具有非正态分布参数的车辆零件的可靠性稳健设计问题,提出了可靠性稳健设计的计算方法。把可靠性灵敏度溶入可靠性优化设计模型之中,将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四阶矩已知的情况下,通过计算机程序可以实现具有非正态分布参数的车辆零件的可靠性稳健设计,迅速准确地得到具有非正态分布参数的车辆零件的可靠性稳健设计信息。数值算例表明所提出的方法是一种非常方便和实用的可靠性稳健设计方法。     

Reliability-based robust optimization design of automobile components with non-normal distribution parameters

In the reliability designing procedure of the vehicle components, when the distribution styles of the random variables are unknown or non-normal distribution, the result evaluated contains great error or even is wrong if the reliability value R is larger than 1 by using the existent method, in which case the formula is necessary to be revised. This is obviously inconvenient for programming. Combining reliability-based optimization theory, robust designing method and reliability based sensitivity analysis, a new method for reliability robust designing is proposed. Therefore the influence level of the designing parameters’ changing to the reliability of vehicle components can be obtained. The reliability sensitivity with respect to design parameters is viewed as a sub-objective function in the multi-objective optimization problem satisfying reliability constraints. Given the first four moments of basic random variables, a fourth-moment technique and the proposed optimization procedure can obtain reliability-based robust design of automobile components with non-normal distribution parameters accurately and quickly. By using the proposed method, the distribution style of the random parameters is relaxed. Therefore it is much closer to the actual reliability problems. The numerical examples indicate the following: (1) The reliability value obtained by the robust method proposed increases (>0.04%) comparing to the value obtained by the ordinary optimization algorithm; (2) The absolute value of reliability-based sensitivity decreases (>0.01%), and the robustness of the products’ quality is improved accordingly. Utilizing the reliability-based optimization and robust design method in the reliability designing procedure reduces the manufacture cost and provides the theoretical basis for the reliability and robust design of the vehicle components.     

非正态随机参数的机械零件的可靠性稳健设计

将可靠性优化设计理论、可靠性灵敏度技术与稳健设计方法相结合,讨论具有非正态随机参数的机械零件的可靠性稳健设计问题,提出可靠性稳健设计的计算方法。将可靠性灵敏度溶入可靠性优化设计模型之中,将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。利用四阶矩技术在基本随机参数的前四阶矩已知的情况下,通过计算机程序可以实现具有非正态随机参数的机械零件的可靠性稳健设计,迅速准确地得到具有非正态随机参数的机械零件的可靠性稳健设计信息。数值算例表明文中所提方法是一种非常方便和实用的可靠性稳健设计方法。     

整体法兰的可靠性稳健优化设计

将可靠性优化设计理论、可靠性灵敏度分析技术与稳健设计方法相结合，讨论整体法兰的可靠性稳健优化设计问题，提出可靠性稳健优化设计的计算方法。把可靠性灵敏度溶入可靠性优化设计模型之中，将可靠性稳健优化设计归结为满足可靠性要求的多目标优化问题。数值算例表明所提出的数值计算方法是一种非常方便和实用的可靠性稳健优化设计方法。     

一种考虑参数相关性的可靠性优化设计方法

在求解具有非线性相关性结构的可靠性设计优化问题时,现有的相关性处理方法在某些情况下可能会得到精度较低的优化结果。基于Copula函数提出了一种可靠性优化设计方法,用于求解存在非线性相关性结构的可靠性优化设计问题。该方法根据已知的样本对各备选Copula函数进行参数估计,并根据AIC准则选出最优Copula函数。根据最优Copula函数,构建联合概率分布函数,最后求解结构可靠性优化设计问题。通过两个数值算例验证了该方法的有效性,并讨论了不同Copula函数对优化结果的影响。     

Reliability-based design for automobiles in China

The level of automobile design and manufacturing is an important sign of leadership in science and technology and economic power. The achievements of theories and methods for reliability-based design of automobiles in China are reviewed. For reliability-based design, the theories and practices, optimization, sensitivity, and robustness are estimated. The techniques of reliability-based design for automobiles are developed. The techniques service to the “hollow” phenomena of kernel technology, product innovative power, and independent development power can be solved.     

车辆转向机构运动精度的可靠性稳健优化设计

在车辆转向机构设计中,考虑了可控因素和噪声因素对运动精度的影响,将可靠性优化和稳健设计方法相结合,以转向机构运动精度为目标函数建立转向机构的可靠性稳健优化数学模型.把运动精度的可靠性灵敏度溶入可靠性优化设计模型之中,将可靠性稳健优化设计转化为满足可靠性要求的多目标优化问题.实例计算表明,考虑制造误差、运动副间隙等不确定因素的影响,可靠性稳健优化设计方法能有效保证转向机构的运动精度和可靠性.     

基于多目标非耦合优化策略的可靠性稳健优化设计

以实现多目标问题的可靠性稳健优化设计为目标,通过对目标函数和约束条件进行灵敏度分析,生成目标函数和约束函数的灵敏度附加项,建立了基于灵敏度附加目标函数的可靠性稳健优化设计模型;基于独立公理,使用正交试验和方差分析技术确定设计变量对各个设计目标的影响程度,将设计参数按无耦合或准耦合设计形式分组,把多目标优化问题单目标化,避免多个设计目标之间的反复权衡;结合增广乘子法,应用MATLAB的优化和符号工具箱来实现钳形盘式制动器的可靠性稳健优化设计。算例表明,提出的稳健设计方法具有较高的精度和可靠度。     

基于贝叶斯理论的结构系统可靠性优化设计

提出一种新的可靠性优化设计方法来解决小样本可靠性优化设计问题。首先用贝叶斯理论进行结构可靠性预测,给出贝叶斯可靠度的概念;然后建立贝叶斯可靠性优化设计的数学模型,提出贝叶斯可靠性优化设计的数值方法。数值算例验证了所提方法的有效性和正确性。     

不完全概率信息牛头刨床机构运动精度可靠性稳健设计

将可靠性优化设计理论、可靠性灵敏度技术与稳健设计方法相结合,讨论不完全概率信息牛头刨床主运动机构运动精度可靠性稳健设计问题.从平面机构的几何约束方程出发,推导机构运动精度误差表达式,建立牛头刨床机构运动精度失效的极限状态方程,提出牛头刨床机构运动精度可靠性稳健设计模型.在已知基本随机参数前四阶矩的情况下,通过计算机程序可以实现牛头刨床机构的运动精度可靠性稳健设计,迅速准确地得到牛头刨床机构的设计信息.     

鱼雷螺钉联接结构可靠性稳健优化设计

将可靠性优化设计理论与可靠性灵敏度分析方法相结合,应用可靠性稳健设计优化理论方法,对鱼雷螺钉联接结构进行了可靠性稳健优化设计.给出了计算分析结果.为工程实际的机械产品的可靠性稳健优化设计提供了理论依据.     

Multi-objective reliability-based optimization for design of trapezoidal labyrinth weirs

In the present research, the reliability-based design optimization (RBDO) of labyrinth weirs has been investigated. The optimization problem is formulated such that the optimal shape of trapezoidal labyrinth weir described by a number of variables is found by minimizing the volume of the trapezoidal labyrinth weir and maximizing the reliability index. The constraint conditions are the weir geometric shape and its different ratios. In order to achieve this purpose, a framework is presented whereby non-dominated sorting genetic algorithm (NSGA-II) is integrated with monte carlo simulation (MCS) method to solve the RBDO approach of trapezoidal labyrinth weirs. The proposed method is applied to UTE Dam labyrinth weir, and the results are compared with the real one. The results show the need for design based on reliability in the labyrinth weirs that propose using RBDO for weir design. The results showed that RBDO approach can achieve a more reliable design in addition to reducing the volume of the trapezoidal labyrinth weir. Finally, the sensitivity analysis of the parameters effective on the reliability index revealed that three design variables of weir width, total upstream head and discharge coefficient are the main parameters affecting weir RBDO solution.     

空心传动轴的可靠性稳健优化设计

在以单目标为主要型式的普通可靠性优化设计模型的基础上，考虑把可靠性灵敏度也作为一个目标函数融入到可靠性优化设计中，建立起空心传动轴的多目标可靠性稳健优化设计模型。并结合实例说明可靠性稳健优化设计方法比传统设计方法更实用。     

任意分布参数的梁结构可靠性优化设计

在可靠性设计理论和优化设计方法的基础上,讨论了任意分布参数的梁结构可靠性优化设计问题,提出了任意分布参数的梁结构可靠性优化设计的计算方法。在基本随机参数的前四阶矩已知的情况下,通过计算机程序可以实现任意分布参数的梁结构可靠性优化设计,迅速准确地得到任意分布参数的梁结构可靠性优化设计信息。     

NEW APPROACH FOR RELIABILITY- BASED DESIGN OPTIMIZATION： MINIMUM ERROR POINT

Conventional reliability-based design optimization (RBDO) requires to use the most probable point (MPP) method for a probabilistic analysis of the reliability constraints. A new approach is presented, called as the minimum error point (MEP) method or the MEP based method, for reliability-based design optimization, whose idea is to minimize the error produced by approximating performance functions. The MEP based method uses the first order Taylor's expansion at MEP instead of MPP. Examples demonstrate that the MEP based design optimization can ensure product reliability at the required level, which is very imperative for many important engineering systems. The MEP based reliability design optimization method is feasible and is considered as an alternative for solving reliability design optimization problems. The MEP based method is more robust than the commonly used MPP based method for some irregular performance functions.     

电梯系统垂直振动的频率敏感度分析与鲁棒设计

考虑曳引绳刚度在电梯运行过程中具有变刚度的特性,利用Lagrange方程对电梯系统建立了7自由度的振动微分方程,通过试验设计方法得出随机变量与系统频率响应的数值关系,利用人工神经网络技术获得随机变量与频率响应之间的显性函数关系式。根据激振频率与固有频率之比不超过规定值的关系准则,定义了电梯系统纵向振动的可靠性模式,运用频率可靠性分析方法,提出多频激励情况下的系统的频率可靠性及其敏感度的分析方法。在此基础上,结合可靠性敏感度理论与稳健设计方法,将可靠性敏感度融入到目标优化设计中,建立系统频率可靠性鲁棒设计模型。通过工程算例,将可靠性敏感度理论和稳健设计方法应用到电梯系统设计当中,得到满足鲁棒设计要求的随机参数值。结果表明,该方法具有较高的计算效率和求解精度,可以作为电梯系统稳健设计的理论依据。     

车辆前轴的多目标可靠性稳健优化设计

应用车辆零部件可靠性稳健优化设计的理论方法，对车辆前轴进行了可靠性稳健优化设计。通过模糊多目标粒子群算法求出所有满足约束性条件的pareto解集，结合实际情况，依据pareto解集确定零部件的设计规格。实验证明该方法能迅速有效地获得可靠性稳健设计的信息。     

基于多目标优化策略的螺旋弹簧可靠性稳健优化设计

应用可靠性稳健优化设计理论和多目标决策方法,将车辆螺旋弹簧的可靠性稳健优化设计转化为多目标问题.运用层次分析法选取粒子群算法中的全局极值和个体极值,提出基于层次分析法的多目标粒子群算法,并将该算法应用于可靠性稳健优化设计的多目标模型求解中.与传统方法相比,该方法简便、易行,并能迅速准确地得到车辆螺旋弹簧的可靠性稳健优化设计信息.     

基于四阶矩技术的连杆的可靠性灵敏度设计

基于四阶矩技术,提出了1种连杆的可靠性灵敏度设计的数值计算方法,并对这种计算方法的精确性做了比较,给出了可靠性灵敏度的变化规律,研究了非正态分布参数的改变对连杆可靠性的影响,为分析和修改连杆的可靠性提供了理论依据.     

基于随机有限元的接触问题可靠性形状优化设计

针对含接触的结构可靠性形状优化设计问题，在简要介绍结构可靠性形状优化设计的基础上，重点推导并给出了接触问题的随机有限元的灵敏度全解析分析的表达式，包括可靠度指标的灵敏度分析、接触条件的灵敏度分析及相应的边界支配方程、结构响应量的灵敏度分析等。通过算例，验证了所提出的优化方法的正确性。