共查询到17条相似文献,搜索用时 265 毫秒
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在传统的基于代理模型的冲压稳健性设计中,由于代理模型与真实模型间存在着误差,必然会导致优化结果存在一定的误差。将实验设计、Kriging模型相结合,综合考虑参数不确定性和代理模型不确定性的影响,提出了一种新的冲压稳健性优化设计方法。通过因素敏感性分析筛选出相应的设计变量和噪声因素,基于Kriging模型构建设计参数和质量指标的代理模型,采用蒙特卡罗分析方法以及遗传算法获得最优工艺解。实例分析结果表明,综合两种不确定因素的稳健设计方法能有效地降低拉裂、起皱约束失效概率,提高冲压件成形质量和工艺稳健性。 相似文献
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《机械设计与制造》2016,(9)
车辆定位参数与转向机构在设计过程中,存在诸多不确定性因素,这些将影响机构性能的稳健性。基于ADAMS与i SIGHT搭建基于随机不确定性的定位参数与转向机构的稳健设计模型,采用正交试验方法得到各优化目标的主要因素及各因素之间的交叉影响关系,依据试验数据建立优化目标与设计变量之间的二阶响应面近似模型。综合考虑定位参数、转向梯形机构的尺寸误差、安装误差等随机不确定性因素,应用田口方法建立了定位参数和转向梯形机构的稳健设计模型,并通过与传统设计方法的对比验证了田口方法的稳健性。应用蒙特卡洛法保证了转向过程中转向轮转角的精度,应用可靠性优化方法保证了转向机构传动角约束的可靠性。 相似文献
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首先通过对优化问题的表述,说明稳健优化与传统确定性优化的区别。稳健优化需进行不确定性分析,为此对目标的均值和方差同时进行优化。然后分析和比较了蒙特卡罗法、基于敏感度法、解析法、基于代理模型法等不确定性分析方法的特点,其中着重介绍了基于代理模型的不确定性分析方法。最后讨论了2类求解稳健优化问题的策略:加权法和多目标遗传算法。 相似文献
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为合理衡量不确定性因素对撒砂装置最大应力的影响,提升其稳健可靠性水平,文中提出了基于多权值优化代理模型的稳健可靠性设计方法。首先,构建撒砂装置有限元模型并计算其最大应力响应;其次,提取不确定性因素并编制参数化分析文件,进而依据试验设计结果,初步构建不确定性因素与最大应力的代理模型,采用遗传算法对代理模型中传递及加权系数进行优化,提升代理模型对最大应力响应预测结果的合理性;最后,基于稳健可靠性设计思想,建立撒砂装置稳健可靠性优化设计模型,并通过对比分析验证所提方法的有效性。结果表明:多权值优化代理模型最大应力决定系数提升至0.991 8;经稳健可靠性设计得到的撒砂装置最大应力波动标准差减小至1.46 MPa,可为其他工程结构稳健可靠性的设计提供一定参考。 相似文献
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首先通过对优化问题的表述,说明稳健优化与传统确定性优化的区别.稳健优化需进行不确定性分析,为此对目标的均值和方差同时进行优化.然后分析和比较了蒙特卡罗法、基于敏感度法、解析法、基于代理模型法等不确定性分析方法的特点,其中着重介绍了基于代理模型的不确定性分析方法.最后讨论了2类求解稳健优化问题的策略:加权法和多目标遗传算法. 相似文献
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Metamodeling techniques have been used in robust optimization to reduce the high computational cost of the uncertainty analysis and improve the performance of robust optimization problems with computationaUy expensive simulation models.Existing metamodels main focus on polynomial regression(PR),neural networks(NN)and Kriging models,these metamodeis are not well suited for large-scale robust optimization problems with small size training sets and high nonlinearity.To address the problem,a reduced approximation model technique based on support vector regression(SVR)is introduced in order to improve the accuracy of metamodels.A robust optimization method based on SVR is presented for problems that involve high dimension and nonlinear.First appropriate design parameter samples are selected by experimental design theories,then the response samples are obtained from the simulations such as finite element analysis,the SVR metamodel is constructed and treated as the mean and the variance of the objective performance functions.Combining other constraints,the robust optimization model is formed which can be solved by genetic algorithm(GA).The applicability of the method developed is demonstrated using a case of two-bar structure system study.The performances of SVR were compared with those of PR,Kriging and back-propagation neural networks(BPNN),the comparison results show that the prediction accuracy of the SVR metamodel was higher than those of other metamodels under uncertainty.The robust optimization solutions are near to the real result,and the proposed method is found to be accurate and efficient for robust optimization.This reaserch provides an efficient method for robust optimization problems with complex structure. 相似文献
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Robust design optimization method for centrifugal impellers under surface roughness uncertainties due to blade fouling 总被引:1,自引:0,他引:1
Blade fouling has been proved to be a great threat to compressor performance in operating stage. The current researches on fouling-induced performance degradations of centrifugal compressors are based mainly on simplified roughness models without taking into account the realistic factors such as spatial non-uniformity and randomness of the fouling-induced surface roughness. Moreover, little attention has been paid to the robust design optimization of centrifugal compressor impellers with considerations of blade fouling. In this paper, a multi-objective robust design optimization method is developed for centrifugal impellers under surface roughness uncertainties due to blade fouling. A three-dimensional surface roughness map is proposed to describe the nonuniformity and randomness of realistic fouling accumulations on blades. To lower computational cost in robust design optimization, the support vector regression (SVR) metamodel is combined with the Monte Carlo simulation (MCS) method to conduct the uncertainty analysis of fouled impeller performance. The analyzed results show that the critical fouled region associated with impeller performance degradations lies at the leading edge of blade tip. The SVR metamodel has been proved to be an efficient and accurate means in the detection of impeller performance variations caused by roughness uncertainties. After design optimization, the robust optimal design is found to be more efficient and less sensitive to fouling uncertainties while maintaining good impeller performance in the clean condition. This research proposes a systematic design optimization method for centrifugal compressors with considerations of blade fouling, providing a practical guidance to the design of advanced centrifugal compressors. 相似文献
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结合模态区间分析及响应面的相关理论,提出一种新的不确定性参数识别方法,即模态区间逆响应面法。首先,以有界区间数来量化结构参数的不确定性,通过合理的实验设计确定样本数据;然后,以响应为输入,设计参数为输出,采用逐步回归分析构造设计参数与结构响应的模态区间逆响应面模型,进而直接在模态区间逆响应面模型上进行模态区间运算,即可识别材料参数的变异性区间;最后,采用一组钢板模态实验来验证所提方法的可行性及可靠性。结果表明:所提方法可准确识别钢板材料参数的取值区间,有效地解决多重变量区间运算存在的区间过估计问题,识别过程避免区间迭代优化,具有较高的计算效率。 相似文献
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Robust design technology has been applied to versatile engineering problems to ensure consistency in product performance.
Since 1980s, the concept of robust design has been introduced to numerical optimization field, which is called the robust
optimization. The robustness in the robust optimization is determined by a measure of insensitiveness with respect to the
variation of a response. However, there are significant difficulties associated with the calculation of variations represented
as its mean and variance. To overcome the current limitation, this research presents an implementation of the approximate
statistical moment method based on kriging metamodel. Two sampling methods are simultaneously utilized to obtain the sequential
surrogate model of a response. The statistics such as mean and variance are obtained based on the reliable kriging model and
the second-order statistical approximation method. Then, the simulated annealing algorithm of global optimization methods
is adopted to find the global robust optimum. The mathematical problem and the two-bar design problem are investigated to
show the validity of the proposed method. 相似文献
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