Damage alarming and safety evaluation using long-term monitoring data is an area of significant research activity for long-span bridges. In order to extend the research in this field, the damage alarming technique for...Damage alarming and safety evaluation using long-term monitoring data is an area of significant research activity for long-span bridges. In order to extend the research in this field, the damage alarming technique for bridge expansion joints based on long-term monitoring data was developed. The effects of environmental factors on the expansion joint displacement were analyzed. Multiple linear regression models were obtained to describe the correlation between displacements and the dominant environmental factors. The damage alarming index was defined based on the multiple regression models. At last, the X-bar control chart was utilized to detect the abnormal change of the displacements. Analysis results reveal that temperature and traffic condition are the dominant environmental factors to influence the displacement. When the confidence level of X-bar control chart is set to be 0.003, the false-positive indications of damage can be avoided. The damage sensitivity analysis shows that the proper X-bar control chart can detect 0.1 cm damage-induced change of the expansion joint displacement. It is reasonably believed that the proposed technique is robust against false-positive indication of damage and suitable to alarm the possible future damage of the expansion joints.展开更多
The joint optimization of production,maintenance,and quality control has shown effectiveness in reducing long-term operational costs in production systems.However,existing studies often assume that changes in the mean...The joint optimization of production,maintenance,and quality control has shown effectiveness in reducing long-term operational costs in production systems.However,existing studies often assume that changes in the mean value of product quality characteristics in a deteriorating system follow a specific distribution while keeping variance constant.To address this limitation,we propose an innovative method based on the continuous ranking probability score(CRPS).This method enables the simultaneous detection of changes in mean and variance in nonconformities,thus removing the assumption of a specific distribution for quality characteristics.Our approach focuses on developing optimal strategies for production,maintenance,and quality control to minimize cost per unit of time.Additionally,we employ a stochastic model to optimize the production time allocated to the inventory buffer,resulting in significant cost reductions.The effectiveness of our proposed joint optimization method is demonstrated through comprehensive numerical experiments,sensitivity analysis,and a comparative study.The results show that our method can achieve cost reductions compared to several other related methods,highlighting its practical applicability for manufacturing companies aiming to reduce costs.展开更多
针对最小均方误差(Minimum Mean Square Error,MMSE)受控过程联合监控可控输入与过程输出这一问题,在任意阶自回归AR(p)平稳扰动模型下开发了一种通用的联合控制图,并将界内点排列非随机判异规则引入其中.同时,对AR(p)平稳扰动模型下生...针对最小均方误差(Minimum Mean Square Error,MMSE)受控过程联合监控可控输入与过程输出这一问题,在任意阶自回归AR(p)平稳扰动模型下开发了一种通用的联合控制图,并将界内点排列非随机判异规则引入其中.同时,对AR(p)平稳扰动模型下生产过程的MMSE控制器和输入与输出的平均链长(Average Run Length,ARL)进行了推导.最后,通过仿真实验验证了该联合控制图的有效性.展开更多
针对输出质量特性服从正态分布的随机偏移单部件可修系统,研究了可变样本容量和控制线(Variable Sampling Size and Control Limits,VSSCL)均值控制图和预防维修策略联合经济设计问题。首先,构建了VSSCL均值控制图和预防维修策略联合经...针对输出质量特性服从正态分布的随机偏移单部件可修系统,研究了可变样本容量和控制线(Variable Sampling Size and Control Limits,VSSCL)均值控制图和预防维修策略联合经济设计问题。首先,构建了VSSCL均值控制图和预防维修策略联合经济设计的集成框架,揭示控制图和预防维修策略运行的耦合机制;然后,基于VSSCL均值控制图和系统状态特征参数,针对给出的集成框架确定了可能形成系统更新的四个维修事件的发生概率,并进一步利用更新过程理论和全概率公式,建立了VSSCL均值控制图和预防维修策略联合经济设计的平均单位时间成本最小决策模型;同时,针对具体实例,将构建的联合设计决策模型和独立设计决策模型进行比较分析,结果表明联合设计决策模型具有明显的经济优势;最后,利用回归正交试验设计方法对模型参数的灵敏度进行了分析。展开更多
基金Project(2009BAG15B03) supported by the National Science and Technology Ministry of ChinaProjects(51178100, 51078080) supported by the National Natural Science Foundation of China+1 种基金Project(BK2011141) supported by the Natural Science Foundation of Jiangsu Province, ChinaProject(12KB02) supported by the Open Fund of the Key Laboratory for Safety Control of Bridge Engineering(Changsha University of Science and Technology), Ministry of Education, China
文摘Damage alarming and safety evaluation using long-term monitoring data is an area of significant research activity for long-span bridges. In order to extend the research in this field, the damage alarming technique for bridge expansion joints based on long-term monitoring data was developed. The effects of environmental factors on the expansion joint displacement were analyzed. Multiple linear regression models were obtained to describe the correlation between displacements and the dominant environmental factors. The damage alarming index was defined based on the multiple regression models. At last, the X-bar control chart was utilized to detect the abnormal change of the displacements. Analysis results reveal that temperature and traffic condition are the dominant environmental factors to influence the displacement. When the confidence level of X-bar control chart is set to be 0.003, the false-positive indications of damage can be avoided. The damage sensitivity analysis shows that the proper X-bar control chart can detect 0.1 cm damage-induced change of the expansion joint displacement. It is reasonably believed that the proposed technique is robust against false-positive indication of damage and suitable to alarm the possible future damage of the expansion joints.
基金supported by National Natural Science Foundation of China(Grant Nos.72101177,72231005,72261147706,and 72371183)State Administration of Science,Technology and Industry for National Defense,China(Grant Nos.JSZL2021204B001,and JSZL2022204B005)Tianjin Natural Science Foundation(Grant No.22JCQNJC01190).
文摘The joint optimization of production,maintenance,and quality control has shown effectiveness in reducing long-term operational costs in production systems.However,existing studies often assume that changes in the mean value of product quality characteristics in a deteriorating system follow a specific distribution while keeping variance constant.To address this limitation,we propose an innovative method based on the continuous ranking probability score(CRPS).This method enables the simultaneous detection of changes in mean and variance in nonconformities,thus removing the assumption of a specific distribution for quality characteristics.Our approach focuses on developing optimal strategies for production,maintenance,and quality control to minimize cost per unit of time.Additionally,we employ a stochastic model to optimize the production time allocated to the inventory buffer,resulting in significant cost reductions.The effectiveness of our proposed joint optimization method is demonstrated through comprehensive numerical experiments,sensitivity analysis,and a comparative study.The results show that our method can achieve cost reductions compared to several other related methods,highlighting its practical applicability for manufacturing companies aiming to reduce costs.
文摘针对最小均方误差(Minimum Mean Square Error,MMSE)受控过程联合监控可控输入与过程输出这一问题,在任意阶自回归AR(p)平稳扰动模型下开发了一种通用的联合控制图,并将界内点排列非随机判异规则引入其中.同时,对AR(p)平稳扰动模型下生产过程的MMSE控制器和输入与输出的平均链长(Average Run Length,ARL)进行了推导.最后,通过仿真实验验证了该联合控制图的有效性.
文摘针对输出质量特性服从正态分布的随机偏移单部件可修系统,研究了可变样本容量和控制线(Variable Sampling Size and Control Limits,VSSCL)均值控制图和预防维修策略联合经济设计问题。首先,构建了VSSCL均值控制图和预防维修策略联合经济设计的集成框架,揭示控制图和预防维修策略运行的耦合机制;然后,基于VSSCL均值控制图和系统状态特征参数,针对给出的集成框架确定了可能形成系统更新的四个维修事件的发生概率,并进一步利用更新过程理论和全概率公式,建立了VSSCL均值控制图和预防维修策略联合经济设计的平均单位时间成本最小决策模型;同时,针对具体实例,将构建的联合设计决策模型和独立设计决策模型进行比较分析,结果表明联合设计决策模型具有明显的经济优势;最后,利用回归正交试验设计方法对模型参数的灵敏度进行了分析。
