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...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.展开更多
In this paper we consider the fully discrete local discontinuous Galerkin method, where the third order explicit Runge-Kutta time marching is coupled. For the one-dimensional time-dependent singularly perturbed proble...In this paper we consider the fully discrete local discontinuous Galerkin method, where the third order explicit Runge-Kutta time marching is coupled. For the one-dimensional time-dependent singularly perturbed problem with a boundary layer, we shall prove that the resulted scheme is not only of good behavior at the local stability, but also has the double-optimal local error estimate. It is to say, the convergence rate is optimal in both space and time, and the width of the cut-off subdomain is also nearly optimal, if the boundary condition at each intermediate stage is given in a proper way. Numerical experiments are also given.展开更多
文摘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.
文摘In this paper we consider the fully discrete local discontinuous Galerkin method, where the third order explicit Runge-Kutta time marching is coupled. For the one-dimensional time-dependent singularly perturbed problem with a boundary layer, we shall prove that the resulted scheme is not only of good behavior at the local stability, but also has the double-optimal local error estimate. It is to say, the convergence rate is optimal in both space and time, and the width of the cut-off subdomain is also nearly optimal, if the boundary condition at each intermediate stage is given in a proper way. Numerical experiments are also given.
