探究缺陷效应对焊接件疲劳性能的影响是控制焊接质量的重要内容. 文中引入焊接缺陷参数的影响，基于累计寿命-临界损伤建立含缺陷承载十字焊接接头疲劳可靠性分析模型.首先，根据结构件焊缝和缺陷参数以及载荷条件，建立有限元计算模型，并基于平均应变能密度方法(average strain energy density method，SED)和热点应力方法(hot spot method，HS)等评估方法探究各特征参数对疲劳性能的影响.其次，结合BP神经网络和Miner线性累计损伤准则建立可靠性分析模型，以概率统计相关参数为基础系统分析疲劳载荷和变异系数对于疲劳可靠性指标的影响.结果表明，位移和角错位及其概率分布参数显著影响焊件的疲劳寿命分布及可靠性概率，该可靠性模型为工程焊件的疲劳寿命设计及监测检修提供参考依据.
Exploring the effect of defects on the fatigue performance of welded joints is an important content in controlling the quality of welding process. This paper introduces the defect effects, based on cumulative life-critical damage to establish fatigue reliability analysis model of misaligned load-carrying cruciform welded joints. First, the finite element models were established based on the geometrical and defect characteristics and cyclic loading conditions of experimental specimens. Then the fatigue performance of local parameters were explored based on the average strain energy density method (SED) and hot spot stress method (HS). Secondly, a reliability analysis model was established by combining BP neural network and Miner's linear cumulative damage theory to quantitatively analyze the effects of cycle loading, coefficient of variation on fatigue reliability and fatigue damage. The results show the axial and angular misalignments and their probability distribution parameters significantly affect the fatigue life distribution and reliability probability of welded joints. The reliability model provides a reference method for fatigue life design to monitoring and maintenance engineering weldments.
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