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
Deep rock mass possesses some unusual properties due to high earth stress,which further result in new problems that have not been well understood and explained up to date.In order to investigate the deformation mechan...Deep rock mass possesses some unusual properties due to high earth stress,which further result in new problems that have not been well understood and explained up to date.In order to investigate the deformation mechanism,the complete deformation process of deep rock mass,with a great emphasis on local shear deformation stage,was analyzed in detail.The quasi continuous shear deformation of the deep rock mass is described by a combination of smooth functions:the averaged distribution of the original deformation field,and the local discontinuities along the slip lines.Hence,an elasto-plastic model is established for the shear deformation process,in which the rotational displacement is taken into account as well as the translational component.Numerical analysis method was developed for case study.Deformation process of a tunnel under high earth stress was investigated for verification.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.
基金Project(50825403) supported by the National Science Fund for Distinguished Young ScholarsProject(2010CB732003) supported by the National Key Basic Research Program of ChinaProject(51021001) supported by the Science Fund for Creative Research Group of the National Natural Science Foundation of China
文摘Deep rock mass possesses some unusual properties due to high earth stress,which further result in new problems that have not been well understood and explained up to date.In order to investigate the deformation mechanism,the complete deformation process of deep rock mass,with a great emphasis on local shear deformation stage,was analyzed in detail.The quasi continuous shear deformation of the deep rock mass is described by a combination of smooth functions:the averaged distribution of the original deformation field,and the local discontinuities along the slip lines.Hence,an elasto-plastic model is established for the shear deformation process,in which the rotational displacement is taken into account as well as the translational component.Numerical analysis method was developed for case study.Deformation process of a tunnel under high earth stress was investigated for verification.
