Process planning for large complicated stampings is more complicated, illegible and multiform than that for common stampings. In this paper, an intelligent master model of computer aided process planning （CAPP） for ...Process planning for large complicated stampings is more complicated, illegible and multiform than that for common stampings. In this paper, an intelligent master model of computer aided process planning （CAPP） for large complicated stampings has been developed based on knowledge based engineering （KBE） and feature technology. This innovative model consists of knowledge base （KB）, process control structure （PCS）, process information model （PIM）, multidisciplinary design optimization （MDO）, model link environment （MLE） and simulation engine （SE）, to realize process planning, optimization, simulation and management integrated to complete intelligent CAPP system. In this model, KBE provides knowledge base, open architecture and knowledge reuse ability to deal with the multi-domain and multi-expression of process knowledge, and forms an integrated environment. With PIM, all the knowledge consisting of objects, constraints, cxtmricncc and decision-makings is carried by object-oriented method dynamically for knowledge-reasoning. PCS makes dynamical knowledge modified and updated timely and accordingly. MLE provides scv. cral methods to make CAPP sysmm associated and integrated. SE provides a programmable mechanism to interpret simulation course and result. Meanwhile, collaborative optimization, one method of MDO, is imported to deal with the optimization distributed for multiple purposes. All these make CAPP sysmm integrated and open to other systems, such as dic design and manufacturing system.展开更多
Stamping is a critical step in the manufacture of metallic bipolar plates.Typically,residual stress and a spring back effect appear on the bipolar plate after the stamping process,which impacts on the performance and ...Stamping is a critical step in the manufacture of metallic bipolar plates.Typically,residual stress and a spring back effect appear on the bipolar plate after the stamping process,which impacts on the performance and lifetime of the proton exchange membrane fuel cell(PEMFC).The residual stress and spring back behavior which occur as a result of stamping a bipolar plate are investigated in this study.The effects of the punch radius,the die radius,the channel depth,and the clearance between the punch and the die on the residual stress and forming quality of the bipolar plate are examined.The stamping process can be divided into three stages.The high stress area and the middle section residual stress area were selected to study the formation process and to obtain the composition of the residual stress regions.Spring back was mainly related to the position of the fixed end of the sheet and the degree of plastic deformation,and the sheet thickness have increased by 2μm after spring back.Based on the results of finite element analysis,as described by the distribution of residual stress,the formation,the thickness of the middle cross section and the equivalent plastic strain,it was found that all the tool parameters affected the distribution of the residual stress.This research can provide a design reference for the manufacture of metallic bipolar plates based on the stamping process.展开更多
与传统列控系统相比,全自动无人驾驶运营场景更加复杂多变,潜在的危险及致因具有更强的隐蔽性和复杂性,给运营安全带来了新的挑战。针对以上问题,提出一种STAMP(Systems-Theoretic Accident Model and Process)与模型检验相结合的复杂...与传统列控系统相比,全自动无人驾驶运营场景更加复杂多变,潜在的危险及致因具有更强的隐蔽性和复杂性,给运营安全带来了新的挑战。针对以上问题,提出一种STAMP(Systems-Theoretic Accident Model and Process)与模型检验相结合的复杂运营场景安全验证方法。首先,基于STAMP理论构建运营场景分层控制结构模型,辨识潜在的不安全控制行为、分析危险致因和安全约束;其次,定义分层控制结构模型与安全状态机模型间的基本转换规则,基于分层控制结构模型、安全约束和转换规则,构建运营场景安全状态机模型;最后,针对提取的安全约束,利用数据流图建立安全属性验证模型,结合模型检验技术,对运营场景安全状态机模型进行形式化验证。以全自动无人驾驶运营场景中列车自动进站停车为例,对方法进行验证分析。结果表明,当STAMP理论提取的安全约束通过了场景安全状态机模型的验证时,表示在该场景中对应的不安全控制行为没有发生且不导致相应危险。该方法结合系统安全分析与形式化建模验证的优势,降低了运营场景建模的难度,构建的运营场景形式化模型满足系统安全约束,可以作为全自动无人驾驶系统安全设计和安全改进的重要基础。展开更多
Accidents in engineered systems are usually generated by complex socio-technical factors.It is beneficial to investigate the increasing complexity and coupling of these factors from the perspective of system safety.Ba...Accidents in engineered systems are usually generated by complex socio-technical factors.It is beneficial to investigate the increasing complexity and coupling of these factors from the perspective of system safety.Based on system and control theories,System-Theoretic Accident Model and Processes(STAMP)is a widely recognized approach for accident analysis.In this paper,we propose a STAMP-Game model to analyze accidents in oil and gas storage and transportation systems.Stakeholders in accident analysis by STAMP can be regarded as players of a game.Game theory can,thus,be adopted in accident analysis to depict the competition and cooperation between stakeholders.Subsequently,we established a game model to study the strategies of both supervisory and supervised entities.The obtained results demonstrate that the proposed game model allows for identifying the effectiveness deficiency of the supervisory entity,and the safety and protection altitudes of the supervised entity.The STAMP-Game model can generate quantitative parameters for supporting the behavior and strategy selections of the supervisory and supervised entities.The quantitative data obtained can be used to guide the safety improvement,to reduce the costs of safety regulation violation and accident risk.展开更多
数字化控制是核电发展的必然趋势,核电厂数字化控制系统(Digital Control System,DCS)的应用在提高核电厂系统控制能力的同时也增加了系统的复杂性,以事件链模型为基础的传统安全分析技术面临挑战。为提高核电厂DCS的安全性能,需要关注...数字化控制是核电发展的必然趋势,核电厂数字化控制系统(Digital Control System,DCS)的应用在提高核电厂系统控制能力的同时也增加了系统的复杂性,以事件链模型为基础的传统安全分析技术面临挑战。为提高核电厂DCS的安全性能,需要关注安全工程领域的新研究成果,将其引入到核电安全领域并加以研究。本文介绍一种新的基于系统理论的事故模型和过程(Systems-Theoretic Accident Modeling and Processes,STAMP)安全模型,对比分析了其与传统安全模型的优缺点,说明了基于STAMP的风险分析(STAMP-Based HazardAnalysis,STPA)技术的基本步骤,并根据STAMP在国内外的应用情况,对STAMP在我国核电领域的发展前景进行了展望。展开更多
The rapid development of wearable and portable electronics has dramatically increased the application for miniaturized energy storage components.Stamping micro-supercapacitors(MSCs)with planar interdigital configurati...The rapid development of wearable and portable electronics has dramatically increased the application for miniaturized energy storage components.Stamping micro-supercapacitors(MSCs)with planar interdigital configurations are considered as a promising candidate to meet the requirements.In this review,recent progress of the different stamping materials and various stamping technologies are first discussed.The merits of each material,manufacturing process of each stamping method and the properties of stamping MSCs are scrutinized,respectively.Further insights on technical difficulties and scientific challenges are finally demonstrated,including the limited thickness of printed electrodes,poor overlay accuracy and printing resolution.展开更多
在相关事故概率统计数据缺少的情况下,为提高LNG储备库的整体安全性,解决传统安全性分析方法无法考虑复杂系统内部关联性、事故分析思路较为分散、忽视组件交互及宏观控制的问题,保证液化天然气储备库分层翻滚事故和火灾事故正演结果的...在相关事故概率统计数据缺少的情况下,为提高LNG储备库的整体安全性,解决传统安全性分析方法无法考虑复杂系统内部关联性、事故分析思路较为分散、忽视组件交互及宏观控制的问题,保证液化天然气储备库分层翻滚事故和火灾事故正演结果的准确性,建立基于系统论事故分析模型(Systems-Theoretic Accident Modeling and Process,STAMP)及系统理论过程分析(System-Theoretic Process Analysis,STPA)的LNG储备库典型事故正演模型,使得后续系统隐患分析、事故原因分析的更加全面完善。首先,根据LNG储罐分层翻滚事故和火灾事故过程中涉及的设备设施、工艺流程及相互间的关联关系,对事故进行初步危险分析、辨识导致事故发生的各个因素、找出危险的关键节点,并在此基础上分析事故所在系统的安全需求及对应的安全性约束,包括可能导致事故发生的控制与反馈操作,建立STAMP模型,模型需包含相关设施、组件之间的控制、反馈关系,和控制反馈回路;然后,采用STPA方法识别LNG保障过程中的四种不安全的控制行为(未提供的控制行为、提供错误或不安全供控制行为、未及时提供控制行为、控制行为结束过早),并从控制行为执行不充分、反馈信息错误或不足两方面分析事故整体过程中涉及到的初始值(如储罐LTD参数)、当前状态(如进液操作)以及状态转换(如储罐与冷却完成准备进液),找出导致不安全控制行为的关键原因,建立完整的LNG储备库典型事故正演模型;最后,结合具体事故案例验证分析LNG储备库典型事故正演模型的有效性与可实施性,并将分析结果可视化,以知识图谱的方式直观展现。研究表明:该模型可从控制和约束角度对复杂系统LNG储备库典型事故进行过程分析,使得事故演化过程更加直观、准确,原因梳理更加清晰;从系统的角度考虑了各风险因素在分层翻滚事故和火灾事故正演中的因果关系,为后续LNG储备库的安全管理工作提供了可行、有针对性的价值信息。展开更多
In order t o evaluate inertial effect on sheet deformation in the simulation of stamping pr ocesses by dynamic explicit FEM, an analytic model is established for analyzing cylindrical cup drawing process. The main fa...In order t o evaluate inertial effect on sheet deformation in the simulation of stamping pr ocesses by dynamic explicit FEM, an analytic model is established for analyzing cylindrical cup drawing process. The main factors governing the extent of inerti al effect on sheet deformation pattern are investigated by energy method, and th e approach to the selection of reasonable tool speed for dynamic analysis of sta mping processes is proposed. The effectiveness of the present approach is furthe r demonstrated and justified by the numerical result herewith provided.展开更多
文摘Process planning for large complicated stampings is more complicated, illegible and multiform than that for common stampings. In this paper, an intelligent master model of computer aided process planning （CAPP） for large complicated stampings has been developed based on knowledge based engineering （KBE） and feature technology. This innovative model consists of knowledge base （KB）, process control structure （PCS）, process information model （PIM）, multidisciplinary design optimization （MDO）, model link environment （MLE） and simulation engine （SE）, to realize process planning, optimization, simulation and management integrated to complete intelligent CAPP system. In this model, KBE provides knowledge base, open architecture and knowledge reuse ability to deal with the multi-domain and multi-expression of process knowledge, and forms an integrated environment. With PIM, all the knowledge consisting of objects, constraints, cxtmricncc and decision-makings is carried by object-oriented method dynamically for knowledge-reasoning. PCS makes dynamical knowledge modified and updated timely and accordingly. MLE provides scv. cral methods to make CAPP sysmm associated and integrated. SE provides a programmable mechanism to interpret simulation course and result. Meanwhile, collaborative optimization, one method of MDO, is imported to deal with the optimization distributed for multiple purposes. All these make CAPP sysmm integrated and open to other systems, such as dic design and manufacturing system.
基金This research was supported by the Sichuan Science and Technology Program(2023YFS0355).
文摘Stamping is a critical step in the manufacture of metallic bipolar plates.Typically,residual stress and a spring back effect appear on the bipolar plate after the stamping process,which impacts on the performance and lifetime of the proton exchange membrane fuel cell(PEMFC).The residual stress and spring back behavior which occur as a result of stamping a bipolar plate are investigated in this study.The effects of the punch radius,the die radius,the channel depth,and the clearance between the punch and the die on the residual stress and forming quality of the bipolar plate are examined.The stamping process can be divided into three stages.The high stress area and the middle section residual stress area were selected to study the formation process and to obtain the composition of the residual stress regions.Spring back was mainly related to the position of the fixed end of the sheet and the degree of plastic deformation,and the sheet thickness have increased by 2μm after spring back.Based on the results of finite element analysis,as described by the distribution of residual stress,the formation,the thickness of the middle cross section and the equivalent plastic strain,it was found that all the tool parameters affected the distribution of the residual stress.This research can provide a design reference for the manufacture of metallic bipolar plates based on the stamping process.
文摘与传统列控系统相比,全自动无人驾驶运营场景更加复杂多变,潜在的危险及致因具有更强的隐蔽性和复杂性,给运营安全带来了新的挑战。针对以上问题,提出一种STAMP(Systems-Theoretic Accident Model and Process)与模型检验相结合的复杂运营场景安全验证方法。首先,基于STAMP理论构建运营场景分层控制结构模型,辨识潜在的不安全控制行为、分析危险致因和安全约束;其次,定义分层控制结构模型与安全状态机模型间的基本转换规则,基于分层控制结构模型、安全约束和转换规则,构建运营场景安全状态机模型;最后,针对提取的安全约束,利用数据流图建立安全属性验证模型,结合模型检验技术,对运营场景安全状态机模型进行形式化验证。以全自动无人驾驶运营场景中列车自动进站停车为例,对方法进行验证分析。结果表明,当STAMP理论提取的安全约束通过了场景安全状态机模型的验证时,表示在该场景中对应的不安全控制行为没有发生且不导致相应危险。该方法结合系统安全分析与形式化建模验证的优势,降低了运营场景建模的难度,构建的运营场景形式化模型满足系统安全约束,可以作为全自动无人驾驶系统安全设计和安全改进的重要基础。
基金supported by the National Natural Science Foundation of China(Grant No.52004030)the R&D Program of Beijing Municipal Education Commission(Grant No.KM202310016003)the Exchange Program of High-end Foreign Experts of Ministry of Science and Technology,China(Grant No.G2022178013L)。
文摘Accidents in engineered systems are usually generated by complex socio-technical factors.It is beneficial to investigate the increasing complexity and coupling of these factors from the perspective of system safety.Based on system and control theories,System-Theoretic Accident Model and Processes(STAMP)is a widely recognized approach for accident analysis.In this paper,we propose a STAMP-Game model to analyze accidents in oil and gas storage and transportation systems.Stakeholders in accident analysis by STAMP can be regarded as players of a game.Game theory can,thus,be adopted in accident analysis to depict the competition and cooperation between stakeholders.Subsequently,we established a game model to study the strategies of both supervisory and supervised entities.The obtained results demonstrate that the proposed game model allows for identifying the effectiveness deficiency of the supervisory entity,and the safety and protection altitudes of the supervised entity.The STAMP-Game model can generate quantitative parameters for supporting the behavior and strategy selections of the supervisory and supervised entities.The quantitative data obtained can be used to guide the safety improvement,to reduce the costs of safety regulation violation and accident risk.
文摘数字化控制是核电发展的必然趋势,核电厂数字化控制系统(Digital Control System,DCS)的应用在提高核电厂系统控制能力的同时也增加了系统的复杂性,以事件链模型为基础的传统安全分析技术面临挑战。为提高核电厂DCS的安全性能,需要关注安全工程领域的新研究成果,将其引入到核电安全领域并加以研究。本文介绍一种新的基于系统理论的事故模型和过程(Systems-Theoretic Accident Modeling and Processes,STAMP)安全模型,对比分析了其与传统安全模型的优缺点,说明了基于STAMP的风险分析(STAMP-Based HazardAnalysis,STPA)技术的基本步骤,并根据STAMP在国内外的应用情况,对STAMP在我国核电领域的发展前景进行了展望。
基金the support and funding from China Scholarship Council(CSC)support by the Leibniz Program of the German Research Foundation(SCHM 1298/26-1)。
文摘The rapid development of wearable and portable electronics has dramatically increased the application for miniaturized energy storage components.Stamping micro-supercapacitors(MSCs)with planar interdigital configurations are considered as a promising candidate to meet the requirements.In this review,recent progress of the different stamping materials and various stamping technologies are first discussed.The merits of each material,manufacturing process of each stamping method and the properties of stamping MSCs are scrutinized,respectively.Further insights on technical difficulties and scientific challenges are finally demonstrated,including the limited thickness of printed electrodes,poor overlay accuracy and printing resolution.
文摘在相关事故概率统计数据缺少的情况下,为提高LNG储备库的整体安全性,解决传统安全性分析方法无法考虑复杂系统内部关联性、事故分析思路较为分散、忽视组件交互及宏观控制的问题,保证液化天然气储备库分层翻滚事故和火灾事故正演结果的准确性,建立基于系统论事故分析模型(Systems-Theoretic Accident Modeling and Process,STAMP)及系统理论过程分析(System-Theoretic Process Analysis,STPA)的LNG储备库典型事故正演模型,使得后续系统隐患分析、事故原因分析的更加全面完善。首先,根据LNG储罐分层翻滚事故和火灾事故过程中涉及的设备设施、工艺流程及相互间的关联关系,对事故进行初步危险分析、辨识导致事故发生的各个因素、找出危险的关键节点,并在此基础上分析事故所在系统的安全需求及对应的安全性约束,包括可能导致事故发生的控制与反馈操作,建立STAMP模型,模型需包含相关设施、组件之间的控制、反馈关系,和控制反馈回路;然后,采用STPA方法识别LNG保障过程中的四种不安全的控制行为(未提供的控制行为、提供错误或不安全供控制行为、未及时提供控制行为、控制行为结束过早),并从控制行为执行不充分、反馈信息错误或不足两方面分析事故整体过程中涉及到的初始值(如储罐LTD参数)、当前状态(如进液操作)以及状态转换(如储罐与冷却完成准备进液),找出导致不安全控制行为的关键原因,建立完整的LNG储备库典型事故正演模型;最后,结合具体事故案例验证分析LNG储备库典型事故正演模型的有效性与可实施性,并将分析结果可视化,以知识图谱的方式直观展现。研究表明:该模型可从控制和约束角度对复杂系统LNG储备库典型事故进行过程分析,使得事故演化过程更加直观、准确,原因梳理更加清晰;从系统的角度考虑了各风险因素在分层翻滚事故和火灾事故正演中的因果关系,为后续LNG储备库的安全管理工作提供了可行、有针对性的价值信息。
文摘In order t o evaluate inertial effect on sheet deformation in the simulation of stamping pr ocesses by dynamic explicit FEM, an analytic model is established for analyzing cylindrical cup drawing process. The main factors governing the extent of inerti al effect on sheet deformation pattern are investigated by energy method, and th e approach to the selection of reasonable tool speed for dynamic analysis of sta mping processes is proposed. The effectiveness of the present approach is furthe r demonstrated and justified by the numerical result herewith provided.
