The optimization of inspection intervals for composite structures has been proposed,but only one damage type,dent damage,has been addressed so far.The present study focuses on the two main damage types of dent and del...The optimization of inspection intervals for composite structures has been proposed,but only one damage type,dent damage,has been addressed so far.The present study focuses on the two main damage types of dent and delamination,and a model for optimizing the inspection interval of composite structures is proposed to minimize the total maintenance cost on the premise that the probability of structure failure will not exceed the acceptable level.In order to analyze the damage characteristics and the residual strength of the composite structure,the frequency,energy,size,and depth of the damage are studied,and the situation of missing detection during the inspection is considered.The structural residual strength and total maintenance cost are quantified corresponding to different inspection intervals.The proposed optimization method relieves the constraints in previous simulation methods,and is more consistent with the actual situation.Finally,the outer wing of aircraft is taken as an example,and with the historical cases and experimental data,the optimization method is verified.The optimal inspection interval is shorter than the actually implemented inspection interval,and the corresponding maintenance cost is reduced by 23.3%.The result shows the feasibility and effectiveness of the proposed optimization method.展开更多
Influences of inspecting time-interval and location on varying behavior of metal magnetic memory (MMM) signals of defects were studied. Different areas in two precracked weldments were inspected at different time-inte...Influences of inspecting time-interval and location on varying behavior of metal magnetic memory (MMM) signals of defects were studied. Different areas in two precracked weldments were inspected at different time-intervals by type TSC-1M-4 stress-concentration magnetic inspector to obtain MMM signals. Mechanisms of MMM signals varying behavior with inspecting time and space were analyzed and discussed respectively. It is found that MMM signals don't change with inspecting time-interval, since stress field and magnetic leakage field maintain unchanged at any time after welding. On the other hand, MMM signals differ greatly for different inspecting locations, because stress field and magnetic leakage field are unevenly distributed in defective ferromagnetic materials.展开更多
Large pressure equipment needs to be tested regularly to ensure safe operation;wall-climbing robots can carry the necessary tools to inspect spherical tanks,such as cameras and non-destructive testing equipment.Howeve...Large pressure equipment needs to be tested regularly to ensure safe operation;wall-climbing robots can carry the necessary tools to inspect spherical tanks,such as cameras and non-destructive testing equipment.However,a wall-climbing robot inside a spherical tank cannot be accurately positioned owing to the particularity of the spherical tank structure.This paper proposes a passive support and positioning mechanism fixed in a spherical tank to improve the adsorption capacity and positioning accuracy of the inspection robot.The main body of the mechanism was designed as a truss composed of carbon fiber telescopic rods and can work in spherical tanks with diameters of 4.6-15.7 m.The structural strength,stiffness,and stability of the mechanism are analyzed via force and deformation simulations.By constructing a mathematical model of the support and positioning mechanism,the influence of structural deformation on the supporting capacity is analyzed and calculated.The robot positioning method based on the support and positioning mechanism can effectively locate the robot inside a spherical tank.Experiments verified the support performance and robot positioning accuracy of the mechanism.This research proposes an auxiliary support and positioning mechanism for a detection robot inside a spherical tank,which can effectively improve the positioning accuracy of the robot and meet the robotic inspection requirements.展开更多
This research article is based on a study of optimal frequency to the repairable system due to the failure finding interval to maximize as well as minimize the availability of some components devices. We studied toget...This research article is based on a study of optimal frequency to the repairable system due to the failure finding interval to maximize as well as minimize the availability of some components devices. We studied together maintenance and corrective actions that carried out item of failure and periodic failure finding designed to check whether a system is still working. The model is proved as well as useful application in detecting the problem related to finding failure tasks of different scheme devices by maximization. The model formulated and the numerical application to the relevant mathematical model have been discussed to demonstrate the article quality. Therefore based on probability analytic development, the optimal maintenance policy is then obtained as solution of an optimization problem in which the maintenance cost rate is the objective function and the risk of corrective maintenance is the constraint function. Finally, the solution to the optimal device in the considered development model has been well adjusted due to derivation to the experimental observation rather than theory which will be taken into consideration in the next applied practical design research related and the system device provided that, the proactive device agreed with using the exponential distribution to the survive distribution function which can not be considered as valid.展开更多
This paper proposes an optimal failure-finding interval （FFI） model based on maximizing expected availability. The model can be viewed as an extension and improvement to the model presented in Moubray （1997）. Nume...This paper proposes an optimal failure-finding interval （FFI） model based on maximizing expected availability. The model can be viewed as an extension and improvement to the model presented in Moubray （1997）. Numerical results are also included to illustrate the appropriateness of the proposed model.展开更多
储罐作为石油行业重要基础设施,保证其安全、高效和经济运行具有重要意义。实施罐底板检测是确定储罐系统性能和可靠性的有效手段。根据工程经验或相似案例的特定时间周期可能造成储罐失修或过修。提出基于风险的检验技术(Risk Based In...储罐作为石油行业重要基础设施,保证其安全、高效和经济运行具有重要意义。实施罐底板检测是确定储罐系统性能和可靠性的有效手段。根据工程经验或相似案例的特定时间周期可能造成储罐失修或过修。提出基于风险的检验技术(Risk Based Inspection,RBI),根据罐底板厚度、腐蚀速率、最小允许厚度和可接受风险确定储罐检测周期,更适用于我国储罐实际情况,有利于油库企业降本增效、预防腐蚀穿孔和油品泄漏事故。展开更多
基金supported by the National Natural Science Foundation of China(U1533202)the Fundamental Research Funds for the Central Universities(NP2019408)。
文摘The optimization of inspection intervals for composite structures has been proposed,but only one damage type,dent damage,has been addressed so far.The present study focuses on the two main damage types of dent and delamination,and a model for optimizing the inspection interval of composite structures is proposed to minimize the total maintenance cost on the premise that the probability of structure failure will not exceed the acceptable level.In order to analyze the damage characteristics and the residual strength of the composite structure,the frequency,energy,size,and depth of the damage are studied,and the situation of missing detection during the inspection is considered.The structural residual strength and total maintenance cost are quantified corresponding to different inspection intervals.The proposed optimization method relieves the constraints in previous simulation methods,and is more consistent with the actual situation.Finally,the outer wing of aircraft is taken as an example,and with the historical cases and experimental data,the optimization method is verified.The optimal inspection interval is shorter than the actually implemented inspection interval,and the corresponding maintenance cost is reduced by 23.3%.The result shows the feasibility and effectiveness of the proposed optimization method.
基金Project(50475113) supported by the National Natural Science Foundation of ChinaProject(20030056002) supported by Specialized Research Fund for Doctoral Program of Higher Education, China
文摘Influences of inspecting time-interval and location on varying behavior of metal magnetic memory (MMM) signals of defects were studied. Different areas in two precracked weldments were inspected at different time-intervals by type TSC-1M-4 stress-concentration magnetic inspector to obtain MMM signals. Mechanisms of MMM signals varying behavior with inspecting time and space were analyzed and discussed respectively. It is found that MMM signals don't change with inspecting time-interval, since stress field and magnetic leakage field maintain unchanged at any time after welding. On the other hand, MMM signals differ greatly for different inspecting locations, because stress field and magnetic leakage field are unevenly distributed in defective ferromagnetic materials.
基金Supported by Jiangsu Major Research and Development(Social Development)Project of China(Grant No.BE2016802).
文摘Large pressure equipment needs to be tested regularly to ensure safe operation;wall-climbing robots can carry the necessary tools to inspect spherical tanks,such as cameras and non-destructive testing equipment.However,a wall-climbing robot inside a spherical tank cannot be accurately positioned owing to the particularity of the spherical tank structure.This paper proposes a passive support and positioning mechanism fixed in a spherical tank to improve the adsorption capacity and positioning accuracy of the inspection robot.The main body of the mechanism was designed as a truss composed of carbon fiber telescopic rods and can work in spherical tanks with diameters of 4.6-15.7 m.The structural strength,stiffness,and stability of the mechanism are analyzed via force and deformation simulations.By constructing a mathematical model of the support and positioning mechanism,the influence of structural deformation on the supporting capacity is analyzed and calculated.The robot positioning method based on the support and positioning mechanism can effectively locate the robot inside a spherical tank.Experiments verified the support performance and robot positioning accuracy of the mechanism.This research proposes an auxiliary support and positioning mechanism for a detection robot inside a spherical tank,which can effectively improve the positioning accuracy of the robot and meet the robotic inspection requirements.
文摘This research article is based on a study of optimal frequency to the repairable system due to the failure finding interval to maximize as well as minimize the availability of some components devices. We studied together maintenance and corrective actions that carried out item of failure and periodic failure finding designed to check whether a system is still working. The model is proved as well as useful application in detecting the problem related to finding failure tasks of different scheme devices by maximization. The model formulated and the numerical application to the relevant mathematical model have been discussed to demonstrate the article quality. Therefore based on probability analytic development, the optimal maintenance policy is then obtained as solution of an optimization problem in which the maintenance cost rate is the objective function and the risk of corrective maintenance is the constraint function. Finally, the solution to the optimal device in the considered development model has been well adjusted due to derivation to the experimental observation rather than theory which will be taken into consideration in the next applied practical design research related and the system device provided that, the proactive device agreed with using the exponential distribution to the survive distribution function which can not be considered as valid.
文摘This paper proposes an optimal failure-finding interval （FFI） model based on maximizing expected availability. The model can be viewed as an extension and improvement to the model presented in Moubray （1997）. Numerical results are also included to illustrate the appropriateness of the proposed model.
文摘储罐作为石油行业重要基础设施,保证其安全、高效和经济运行具有重要意义。实施罐底板检测是确定储罐系统性能和可靠性的有效手段。根据工程经验或相似案例的特定时间周期可能造成储罐失修或过修。提出基于风险的检验技术(Risk Based Inspection,RBI),根据罐底板厚度、腐蚀速率、最小允许厚度和可接受风险确定储罐检测周期,更适用于我国储罐实际情况,有利于油库企业降本增效、预防腐蚀穿孔和油品泄漏事故。
