近年来大型体育场馆的数量快速增加,随之而来的突发事件也不断增多。人群拥挤踩踏事故是大型体育场馆较为常见的安全事故,严重威胁到人民的生命安全。为了梳理总结大型体育场馆内人群拥挤踩踏事故发生的致因因素,构建了大型体育场馆人...近年来大型体育场馆的数量快速增加,随之而来的突发事件也不断增多。人群拥挤踩踏事故是大型体育场馆较为常见的安全事故,严重威胁到人民的生命安全。为了梳理总结大型体育场馆内人群拥挤踩踏事故发生的致因因素,构建了大型体育场馆人群拥挤踩踏事故的过程模型。首先,基于系统理论事故模型与过程(systemstheoretic accident model and processes,STAMP)模型分析并构建大型体育场馆人群拥挤踩踏事故的安全控制结构,并依据该模型来识别和确定事故致因因素;其次,利用决策试验与评价实验室法(decision-making trial and evaluation laboratory,DEMATEL)分析踩踏事故各个致因因素之间的相互作用关系,并计算出各个致因因素的中心度、原因度以及权重;最后,辨识出大型体育场馆发生踩踏事故的原因因素、结果因素以及关键致因因素。结果表明,管理队伍未对人群进行正确的引导和疏散通道处发生人群拥堵等为关键致因素。该模型对大型体育场馆的人流管控和安全管理具有一定的参考和支撑作用。展开更多
本文研究了基于系统理论事故模型与过程分析(System-Theoretic Accident Modeling and Process,STAMP)的高速公路隧道机电系统安全评估方法。通过STAMP模型,系统地识别了隧道机电系统中人、技术、组织及环境间的交互关系和潜在失效模式...本文研究了基于系统理论事故模型与过程分析(System-Theoretic Accident Modeling and Process,STAMP)的高速公路隧道机电系统安全评估方法。通过STAMP模型,系统地识别了隧道机电系统中人、技术、组织及环境间的交互关系和潜在失效模式,构建了安全评估框架。通过引入STAMP模型,本文希望能够为高速公路隧道机电系统的安全评估提供一种新的思路和方法,进一步提高评估的科学性和准确性。展开更多
X-ray diffraction(XRD),scanning electron microscopy(SEM),energy-dispersive spectroscopy(EDS),electron backscatter diffraction(EBSD),and transmission electron microscopy(TEM)were used to systematically investigate the ...X-ray diffraction(XRD),scanning electron microscopy(SEM),energy-dispersive spectroscopy(EDS),electron backscatter diffraction(EBSD),and transmission electron microscopy(TEM)were used to systematically investigate the impact of rapid cold stamping on microstructural evolution and mechanical properties of spray-formed Al-Zn-Mg-Cu alloys under ambient conditions.The results reveal that the dislocation density increases with successive cold stamping passes,the volume fraction of the secondary phase(Mg(Zn,Cu,Al)_(2))increases from 15.64% to 23.94%,and the average size decreases from 1.41 to 0.75μm.The pinning effect of the secondary phases on dislocations promotes a significant transformation from low-angle grain boundaries to high-angle grain boundaries,resulting in the average grain size decreasing from 5.75 to 0.97μm.The strength and hardness of the samples increase with successive cold stamping passes,which is attributed to the synergistic effects of dislocation strengthening,grain boundary strengthening,and secondary phase strengthening.展开更多
The impact of various initial states on the ultimate mechanical properties of medium Mn steel(MMnS)following the hot stamping process is revealed.MMnS blanks with three typical initial states were prepared separately,...The impact of various initial states on the ultimate mechanical properties of medium Mn steel(MMnS)following the hot stamping process is revealed.MMnS blanks with three typical initial states were prepared separately,including hot-rolled,cold-rolled and cold-rolled and annealed(CRA).Their microstructures were observed and analyzed by scanning electron microscopy and electron backscatter diffraction,and their mechanical properties were measured by tensile tests following hot stamping and baking treatments.The results reveal that the microstructure of martensite and residual austenite characterizes the hot-stamped MMnS across different rolling conditions,with CRA state exhibiting a clearly higher residual austenite content compared to the other two states.Meanwhile,CRA state boasts not only the highest tensile strength but also the greatest elongation post-hot stamping treatment.The superior comprehensive mechanical properties are attributed to its unique biphase structure of Mn-rich austenite and Mn-poor ferrite,which emerges in CRA state following a 12 h intercritical annealing and can be partially preserved during the hot stamping process.This structure is instrumental in achieving a higher level of residual austenite,consequently leading to enhanced elongation.展开更多
Laser debonding technology has been widely used in advanced chip packaging,such as fan-out integration,2.5D/3D ICs,and MEMS devices.Typically,laser debonding of bonded pairs(R/R separation)is typically achieved by com...Laser debonding technology has been widely used in advanced chip packaging,such as fan-out integration,2.5D/3D ICs,and MEMS devices.Typically,laser debonding of bonded pairs(R/R separation)is typically achieved by completely removing the material from the ablation region within the release material layer at high energy densities.However,this R/R separation method often results in a significant amount of release material and carbonized debris remaining on the surface of the device wafer,severely reducing product yields and cleaning efficiency for ultra-thin device wafers.Here,we proposed an interfacial separation strategy based on laser-induced hot stamping effect and thermoelastic stress wave,which enables stress-free separation of wafer bonding pairs at the interface of the release layer and the adhesive layer(R/A separation).By comprehensively analyzing the micro-morphology and material composition of the release material,we elucidated the laser debonding behavior of bonded pairs under different separation modes.Additionally,we calculated the ablation threshold of the release material in the case of wafer bonding and established the processing window for different separation methods.This work offers a fresh perspective on the development and application of laser debonding technology.The proposed R/A interface separation method is versatile,controllable,and highly reliable,and does not leave release materials and carbonized debris on device wafers,demonstrating strong industrial adaptability,which greatly facilitates the application and development of advanced packaging for ultra-thin chips.展开更多
The forming defects, including thinning, rupture, wrinkling and springback, usually arising in producing a side-door impact beam, were investigated by trial and numerical simulation. A temperature-related constitutive...The forming defects, including thinning, rupture, wrinkling and springback, usually arising in producing a side-door impact beam, were investigated by trial and numerical simulation. A temperature-related constitutive model specific to the temperature range from 350 °C to 500 °C was established and used for the numerical simulation. The trial and numerical simulation were conducted to clarify the quantitative characteristics of forming defects and to analyze the effects of process parameters on the forming defects. Results show that the rupture situation is ameliorated and the springback is eliminated in the aluminum alloy hot stamping. The wrinkling severity decreases with increasing blank holder force (BHF), but the BHF greater than 15 kN causes the rupture at the deepest drawing position of workpiece. The forming defects are avoided with lubricant in the feasible ranges of process parameters: the BHF of 3 to 5 kN and the stamping speed of 50 to 200 mm/s.展开更多
Flow behavior of the Al-Si coated boron steel was investigated with Gleeble-3500,in comparison with the uncoated one.Effect of deformation conditions on the coating integrity was characterized by optical microscopy.Fa...Flow behavior of the Al-Si coated boron steel was investigated with Gleeble-3500,in comparison with the uncoated one.Effect of deformation conditions on the coating integrity was characterized by optical microscopy.Facture surfaces of the coated steels were inspected under SEM.Experimental results indicate that the ultimate tensile strength and ductility of the Al-Si coated boron steel are lower than those of the uncoated steel under test conditions.Extensive cracks occur in the coating after tensile tests;the width and density of cracks are sensitive to the deformation temperatures and strain rates.The bare substrate exposed between the separate coating segments is oxidized.Appearance of the oxide degrades the Al-Si coating adhesion.Remarkable difference between formability of the coating layer and the substrate is confirmed.The formability of the Al-Si coating could be optimized by controlling the phase transformation of the ductile Fe-rich intermetallic compounds within it during the austenization.展开更多
To improve the manufacture efficiency and promote the application of composites in the automobile industry, a new composite forming method, thermal stamping, was discussed to form composite parts directly. Experiments...To improve the manufacture efficiency and promote the application of composites in the automobile industry, a new composite forming method, thermal stamping, was discussed to form composite parts directly. Experiments on two typical stamping processes, thermal bending and thermal deep drawing, were conducted to investigate the forming behavior of composite sheets and analyze the influence of forming temperature on the formed composite part. Experimental results show that the locking angle for woven composite is about 30°. The bending load is smaller than 5 N in the stamping process and decreases with the increase of temperature. The optimal temperature to form the carbon fiber composite is 170 ℃. The die temperature distribution and the deformation of composite sheet were simulated by FEA software ABAQUS. To investigate the fiber movement of carbon woven fabric during stamping, the two-node three-dimension linear Truss unit T2D3 was chosen as the fiber element. The simulation results have a good agreement to the experimental results.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
为分析化学品船智能液货系统的安全性,采用系统理论事故模型与过程(System-Theoretic Accident Model and Processes, STAMP)方法,构建了化学品船智能液货系统控制反馈模型;基于系统理论过程分析(System-Theoretic Process Analysis, ST...为分析化学品船智能液货系统的安全性,采用系统理论事故模型与过程(System-Theoretic Accident Model and Processes, STAMP)方法,构建了化学品船智能液货系统控制反馈模型;基于系统理论过程分析(System-Theoretic Process Analysis, STPA),确定系统级事故,识别不安全控制行为并分析不安全控制行为关键致因;将不安全控制行为作为风险因素,利用三角模糊数对不安全控制行为风险进行量化。结果表明,26种不安全控制行为中,泵管阀动态调节、人员监测、数据采集、货品相容性判定等因素对风险影响程度较高。该分析结果可为化学品船智能液货系统的应用和安全管理提供参考。展开更多
安全生产事故往往由多组织交互、多因素耦合造成,事故原因涉及多个组织。为预防和遏制多组织生产安全事故的发生,基于系统理论事故建模与过程模型(Systems-Theory Accident Modeling and Process,STAMP)、24Model,构建一种用于多组织事...安全生产事故往往由多组织交互、多因素耦合造成,事故原因涉及多个组织。为预防和遏制多组织生产安全事故的发生,基于系统理论事故建模与过程模型(Systems-Theory Accident Modeling and Process,STAMP)、24Model,构建一种用于多组织事故分析的方法,并以青岛石油爆炸事故为例进行事故原因分析。结果显示:STAMP-24Model可以分组织,分层次且有效、全面、详细地分析涉及多个组织的事故原因,探究多组织之间的交互关系;对事故进行动态演化分析,可得到各组织不安全动作耦合关系与形成的事故失效链及管控失效路径,进而为预防多组织事故提供思路和参考。展开更多
文摘近年来大型体育场馆的数量快速增加,随之而来的突发事件也不断增多。人群拥挤踩踏事故是大型体育场馆较为常见的安全事故,严重威胁到人民的生命安全。为了梳理总结大型体育场馆内人群拥挤踩踏事故发生的致因因素,构建了大型体育场馆人群拥挤踩踏事故的过程模型。首先,基于系统理论事故模型与过程(systemstheoretic accident model and processes,STAMP)模型分析并构建大型体育场馆人群拥挤踩踏事故的安全控制结构,并依据该模型来识别和确定事故致因因素;其次,利用决策试验与评价实验室法(decision-making trial and evaluation laboratory,DEMATEL)分析踩踏事故各个致因因素之间的相互作用关系,并计算出各个致因因素的中心度、原因度以及权重;最后,辨识出大型体育场馆发生踩踏事故的原因因素、结果因素以及关键致因因素。结果表明,管理队伍未对人群进行正确的引导和疏散通道处发生人群拥堵等为关键致因素。该模型对大型体育场馆的人流管控和安全管理具有一定的参考和支撑作用。
文摘本文研究了基于系统理论事故模型与过程分析(System-Theoretic Accident Modeling and Process,STAMP)的高速公路隧道机电系统安全评估方法。通过STAMP模型,系统地识别了隧道机电系统中人、技术、组织及环境间的交互关系和潜在失效模式,构建了安全评估框架。通过引入STAMP模型,本文希望能够为高速公路隧道机电系统的安全评估提供一种新的思路和方法,进一步提高评估的科学性和准确性。
基金supported by the National Natural Science Foundation of China(No.52271177).
文摘X-ray diffraction(XRD),scanning electron microscopy(SEM),energy-dispersive spectroscopy(EDS),electron backscatter diffraction(EBSD),and transmission electron microscopy(TEM)were used to systematically investigate the impact of rapid cold stamping on microstructural evolution and mechanical properties of spray-formed Al-Zn-Mg-Cu alloys under ambient conditions.The results reveal that the dislocation density increases with successive cold stamping passes,the volume fraction of the secondary phase(Mg(Zn,Cu,Al)_(2))increases from 15.64% to 23.94%,and the average size decreases from 1.41 to 0.75μm.The pinning effect of the secondary phases on dislocations promotes a significant transformation from low-angle grain boundaries to high-angle grain boundaries,resulting in the average grain size decreasing from 5.75 to 0.97μm.The strength and hardness of the samples increase with successive cold stamping passes,which is attributed to the synergistic effects of dislocation strengthening,grain boundary strengthening,and secondary phase strengthening.
基金supported by the National Key R&D Program of China(No.2022YFE0196600)the National Natural Science Foundation of China(No.52175349)the Shanghai Oriental Talent Program(No.BJKJ2024016).
文摘The impact of various initial states on the ultimate mechanical properties of medium Mn steel(MMnS)following the hot stamping process is revealed.MMnS blanks with three typical initial states were prepared separately,including hot-rolled,cold-rolled and cold-rolled and annealed(CRA).Their microstructures were observed and analyzed by scanning electron microscopy and electron backscatter diffraction,and their mechanical properties were measured by tensile tests following hot stamping and baking treatments.The results reveal that the microstructure of martensite and residual austenite characterizes the hot-stamped MMnS across different rolling conditions,with CRA state exhibiting a clearly higher residual austenite content compared to the other two states.Meanwhile,CRA state boasts not only the highest tensile strength but also the greatest elongation post-hot stamping treatment.The superior comprehensive mechanical properties are attributed to its unique biphase structure of Mn-rich austenite and Mn-poor ferrite,which emerges in CRA state following a 12 h intercritical annealing and can be partially preserved during the hot stamping process.This structure is instrumental in achieving a higher level of residual austenite,consequently leading to enhanced elongation.
基金the National Natural Science Foundation of China(62174170)the Natural Science Foundation of Guangdong Province(2024A1515010123)+4 种基金the Shenzhen Science and Technology Program(20220807020526001)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0670000)the Shenzhen Science and Technology Program(KJZD20230923114708018,KJZD20230923114710022)the Talent Support Project of Guangdong(2021TX06C101)the Shenzhen Basic Research(JCYJ20210324115406019).
文摘Laser debonding technology has been widely used in advanced chip packaging,such as fan-out integration,2.5D/3D ICs,and MEMS devices.Typically,laser debonding of bonded pairs(R/R separation)is typically achieved by completely removing the material from the ablation region within the release material layer at high energy densities.However,this R/R separation method often results in a significant amount of release material and carbonized debris remaining on the surface of the device wafer,severely reducing product yields and cleaning efficiency for ultra-thin device wafers.Here,we proposed an interfacial separation strategy based on laser-induced hot stamping effect and thermoelastic stress wave,which enables stress-free separation of wafer bonding pairs at the interface of the release layer and the adhesive layer(R/A separation).By comprehensively analyzing the micro-morphology and material composition of the release material,we elucidated the laser debonding behavior of bonded pairs under different separation modes.Additionally,we calculated the ablation threshold of the release material in the case of wafer bonding and established the processing window for different separation methods.This work offers a fresh perspective on the development and application of laser debonding technology.The proposed R/A interface separation method is versatile,controllable,and highly reliable,and does not leave release materials and carbonized debris on device wafers,demonstrating strong industrial adaptability,which greatly facilitates the application and development of advanced packaging for ultra-thin chips.
基金Project(P2014-15)supported by the State Key Laboratory of Materials Processing and Die&Mould Technology,Huazhong University of Science and Technology,ChinaProject supported by the Beijing Laboratory of Metallic Materials and Processing for Modern Transportation,China
文摘The forming defects, including thinning, rupture, wrinkling and springback, usually arising in producing a side-door impact beam, were investigated by trial and numerical simulation. A temperature-related constitutive model specific to the temperature range from 350 °C to 500 °C was established and used for the numerical simulation. The trial and numerical simulation were conducted to clarify the quantitative characteristics of forming defects and to analyze the effects of process parameters on the forming defects. Results show that the rupture situation is ameliorated and the springback is eliminated in the aluminum alloy hot stamping. The wrinkling severity decreases with increasing blank holder force (BHF), but the BHF greater than 15 kN causes the rupture at the deepest drawing position of workpiece. The forming defects are avoided with lubricant in the feasible ranges of process parameters: the BHF of 3 to 5 kN and the stamping speed of 50 to 200 mm/s.
基金Project (51275185) supported by the National Natural Science Foundation of China
文摘Flow behavior of the Al-Si coated boron steel was investigated with Gleeble-3500,in comparison with the uncoated one.Effect of deformation conditions on the coating integrity was characterized by optical microscopy.Facture surfaces of the coated steels were inspected under SEM.Experimental results indicate that the ultimate tensile strength and ductility of the Al-Si coated boron steel are lower than those of the uncoated steel under test conditions.Extensive cracks occur in the coating after tensile tests;the width and density of cracks are sensitive to the deformation temperatures and strain rates.The bare substrate exposed between the separate coating segments is oxidized.Appearance of the oxide degrades the Al-Si coating adhesion.Remarkable difference between formability of the coating layer and the substrate is confirmed.The formability of the Al-Si coating could be optimized by controlling the phase transformation of the ductile Fe-rich intermetallic compounds within it during the austenization.
基金Project(51375369)supported by the National Natural Science Foundation of ChinaProject(SYG201137)supported by the Science and Technology Development Program of Suzhou,China
文摘To improve the manufacture efficiency and promote the application of composites in the automobile industry, a new composite forming method, thermal stamping, was discussed to form composite parts directly. Experiments on two typical stamping processes, thermal bending and thermal deep drawing, were conducted to investigate the forming behavior of composite sheets and analyze the influence of forming temperature on the formed composite part. Experimental results show that the locking angle for woven composite is about 30°. The bending load is smaller than 5 N in the stamping process and decreases with the increase of temperature. The optimal temperature to form the carbon fiber composite is 170 ℃. The die temperature distribution and the deformation of composite sheet were simulated by FEA software ABAQUS. To investigate the fiber movement of carbon woven fabric during stamping, the two-node three-dimension linear Truss unit T2D3 was chosen as the fiber element. The simulation results have a good agreement to the experimental results.
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。
文摘为分析化学品船智能液货系统的安全性,采用系统理论事故模型与过程(System-Theoretic Accident Model and Processes, STAMP)方法,构建了化学品船智能液货系统控制反馈模型;基于系统理论过程分析(System-Theoretic Process Analysis, STPA),确定系统级事故,识别不安全控制行为并分析不安全控制行为关键致因;将不安全控制行为作为风险因素,利用三角模糊数对不安全控制行为风险进行量化。结果表明,26种不安全控制行为中,泵管阀动态调节、人员监测、数据采集、货品相容性判定等因素对风险影响程度较高。该分析结果可为化学品船智能液货系统的应用和安全管理提供参考。
文摘安全生产事故往往由多组织交互、多因素耦合造成,事故原因涉及多个组织。为预防和遏制多组织生产安全事故的发生,基于系统理论事故建模与过程模型(Systems-Theory Accident Modeling and Process,STAMP)、24Model,构建一种用于多组织事故分析的方法,并以青岛石油爆炸事故为例进行事故原因分析。结果显示:STAMP-24Model可以分组织,分层次且有效、全面、详细地分析涉及多个组织的事故原因,探究多组织之间的交互关系;对事故进行动态演化分析,可得到各组织不安全动作耦合关系与形成的事故失效链及管控失效路径,进而为预防多组织事故提供思路和参考。
