Abstract

Aiming at the problems of implicit and highly nonlinear limit state function in the process of reliability analysis of mechanical products, a reliability analysis method of mechanical structures based on Kriging model and improved EGO active learning strategy is proposed. For the problem that the traditional EGO method cannot effectively select points in the limit state surface region, an improved EGO method is proposed. By dealing with the predicted values of sample point model with absolute values and assume that the distribution state of response values remains the same, the work focus of active learning selection points is moved to the vicinity, where the points are with larger prediction variance or close to the limit state surface. Three examples show that, compared with the classical active learning method, the proposed method has good global and local search ability, and can estimate the exact failure probability value under the condition of less calculation of the limit state function.

Highlights

  • Structural Reliability Algorithm Based on Improved Dynamic Kriging Model[ J]

  • An Eficient Reliability Analysis Method Combing Adaptive Kriging and Modifed Im⁃ portance Sampling for Small Failure Probability[ J]

  • Reliability Analysis Based on Active Learning Kriging Model[ J]

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Summary

Introduction

主动学习方法的基本原理就是通过学习函数, 在大量 Monte Carlo 模拟样本点中选择最佳样本点, 并将该样本点加入初始样本实验点,对 Kriging 模型 进行更新,如此循环迭代直至达到相关停止要求。 通过主动学习方法,仅需要少量的初始样本点和主 动学习筛选策略就可以构建高精度的代理模型,较 传统方法较好提升了计算效率。 2.1 EGO 主动学习方法 EGO 主动学习方法是由 Jones 等初次提出的用 于复杂函数的代理模型优化,基于 Kriging 代理模 型,采用 EI 函数指标计算样本点处对模型的期望改 善程度,最大 EI 函数值对应的样本点用于模型的再 当前 Kriging 模型的最小值作为最佳函数值 Gmin,当 抽样得到点 x 的时候,并不知道其真实响应值 G(x) 由图 2 可知:1EGO 方法在极限状态面附近的 拟合情况依然十分不理想,选点主要在极限状态函 数最小值附近,导致最佳样本点集中在图 2a) 的外 围;2本文所提出的 IEGO 主动学习方法,对于这种

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