Key methods developed and used in the USSR and in the Russian Federation to determine the impact and friction sensitivity of energetic materials and explosives have been discussed.Experimental methodologies and instru...Key methods developed and used in the USSR and in the Russian Federation to determine the impact and friction sensitivity of energetic materials and explosives have been discussed.Experimental methodologies and instruments that underlie the assessment of their production and handling safety have been described.Studies of a large number of compounds have revealed relationships between their sensitivity parameters and structure of individual compounds and compositions.The range of change of physical and chemical characteristics for the compounds we examined covers the entire region of their existence.Theoretical methodology and equations have been formulated to estimate the impact and friction sensitivity parameters of energetic materials and to evaluate the technological safety in use.The developed methodology is characterized by high-accuracy calculations and prediction of sensitivity parameters.展开更多
In this paper, the exact Bayesian limits, taking conjugate and noninformative prior distribution, and the exact fiducial limits for the mean of the lognormal distribution are presented. They can be found iteratively b...In this paper, the exact Bayesian limits, taking conjugate and noninformative prior distribution, and the exact fiducial limits for the mean of the lognormal distribution are presented. They can be found iteratively by one-dimension integral on a finite interval. The new algorithm is very convenient and with high accuracy. It can meet the practical engineering need excellently. However, the primitive algorithm is rather cumbersome. By the way, the very close approximate limits with a simple algorithm are derived. They can be applied immediately to engineering. Otherwise, they can also be used as a search interval to find the root of equation for the exact limits.展开更多
This article demonstrates a novel approach for material nonlinear analysis.This analysis procedure eliminates tedious and lengthy step by step incremental and then iterative procedure adopted classically and gives dir...This article demonstrates a novel approach for material nonlinear analysis.This analysis procedure eliminates tedious and lengthy step by step incremental and then iterative procedure adopted classically and gives direct results in the linear as well as in nonlinear range of the material behavior.Use of elastic moduli is eliminated.Instead,stress and strain functions are used as the material input in the analysis procedure.These stress and strain functions are directly derived from the stress-strain behavior of the material by the method of curve fitting.This way,the whole stress-strain diagram is utilized in the analysis which naturally exposes the response of structure when loading is in nonlinear range of the material behavior.It is found that it is an excellent computational procedure adopted so far for material nonlinear analysis which gives very accurate results,easy to adopt and simple in calculations.The method eliminates all types of linearity assumptions in basic derivations of equations and hence,eliminates all types of possibility of errors in the analysis procedure as well.As it is required to know stress distribution in the structural body by proper modelling and structural idealization,the proposed analysis approach can be regarded as stress-based analysis procedure.Basic problems such as uniaxial problem,beam bending,and torsion problems are solved.It is found that approach is very suitable for solving the problems of fracture mechanics.Energy release rate for plate with center crack and double cantilever beam specimen is also evaluated.The approach solves the fracture problem with relative ease in strength of material style calculations.For all problems,results are compared with the classical displacement-based liner theory.展开更多
随着我国山区高速公路建设的不断推进,弃渣场地的稳定性及致灾机制成为工程建设评估的重要因素之一。为了实现弃渣场的稳定性、失稳灾害动力学全过程的分析,基于面向GPU并行高性能计算软件CoSim中的物质点法(material point method,简称...随着我国山区高速公路建设的不断推进,弃渣场地的稳定性及致灾机制成为工程建设评估的重要因素之一。为了实现弃渣场的稳定性、失稳灾害动力学全过程的分析,基于面向GPU并行高性能计算软件CoSim中的物质点法(material point method,简称MPM),引入强度折减法(strength reduction method,简称SRM)开展相关研究工作。为了验证算法的合理性,以典型均质边坡为例,采用基于MPM的强度折减法与极限平衡法(limit equilibrium method,简称LEM)进行了对比,表明两者无论在稳定系数Fs还是在潜在滑动面上均具有良好的一致性。在此基础上,以云南某高速公路弃渣场降雨诱发失稳灾害为例,对其在天然工况和暴雨工况下稳定性和失稳过程进行了分析。结果表明,该弃渣场边坡在天然状态下处于稳定状态,而在暴雨工况下会发生失稳和大变形滑动;数值模拟和现场调查结果吻合较好,表明了提出的方法在弃渣场边坡稳定性与大变形失稳动力学分析中有强大的优势,可以实现斜坡的“稳定性→大变形→流动→堆积”的全过程分析。展开更多
基于可视化文献计量工具CiteSpace和文献分析,利用Web of Science核心库的文献题录数据源,对2000—2022年全球抗静电高分子材料的研究热点和发展趋势进行了分析和归纳。文献记录的时空分析表明2006年开始中国的科研力量主导了该领域的发...基于可视化文献计量工具CiteSpace和文献分析,利用Web of Science核心库的文献题录数据源,对2000—2022年全球抗静电高分子材料的研究热点和发展趋势进行了分析和归纳。文献记录的时空分析表明2006年开始中国的科研力量主导了该领域的发展,并在2016年后引领该领域快速增长。合作关系图谱分析表明我国虽未形成核心作者群,但研究力量局部集中。通过对关键词聚类,将抗静电高分子材料的研究内容分为材料性能、材料制备、材料应用和抗静电剂4个部分;通过中介中心性探讨了聚类之间的逻辑关系。根据关键词时区图谱揭示了抗静电高分子材料演进路径和发展趋势,关键词突现表明石墨烯及其衍生物和离子液体作为抗静电剂有望成为下一阶段的前沿热点;将不同抗静电剂复用,以发挥协同效应将成为新的技术路径。展开更多
A four-bar linkage mechanism with links fabricated from symmetric laminates was studied. The mass matrix of the beam dement was obtained in light of the mass distribution characteristics of composite materials. The st...A four-bar linkage mechanism with links fabricated from symmetric laminates was studied. The mass matrix of the beam dement was obtained in light of the mass distribution characteristics of composite materials. The stiffness matrix of the beam element was derived from the constitutive equations of each layer and the relationship between the strain distribution and the node displacement of the beam element. The specific damping capacity of the beam element was analyzed according to the strain distribution of the beam element and the strain energy dissipation caused by vibration in each direction of each layer; and the damping coefficients were obtained according to the principle that the total energy dissipation of the beam element was equal to the work done by the equivalent damping force during a cycle of vibration, from which the damping matrix of the dynamic equations was obtained. Using the finite element method, the dynamic analytic model of the mechanism was obtained. The dynamic responses and natural frequency of the mechanism were obtained by simulation, respectively, and those of the simulation obtained by the proposed model were analyzed and compared with the results obtained by the conventional model. The work provides theoretical basis to a certain extent for the further research on nonlinear vibration characteristics and optimum design of this kind of mechanism.展开更多
为了提高建筑施工安全风险管理的信息化水平,以建筑施工活动及事故风险类型为研究对象,建立施工安全知识图谱。通过知识图谱改进作业条件危险性评价法(LEC)实现安全风险的定量计算,并基于知识图谱进行风险位置识别和不安全因素分析。研...为了提高建筑施工安全风险管理的信息化水平,以建筑施工活动及事故风险类型为研究对象,建立施工安全知识图谱。通过知识图谱改进作业条件危险性评价法(LEC)实现安全风险的定量计算,并基于知识图谱进行风险位置识别和不安全因素分析。研究提出安全风险虚体实化理念,实现了安全风险信息在数字空间实体化表达;基于建筑信息模型(Building Information Modeling, BIM)和知识图谱技术,建立了建筑施工安全风险信息模型(Building Construction Safety Risk Information Model, BCSRIM)。该模型有效避免了传统LEC法中主观因素产生的影响,实现了建筑施工安全风险定量计算、风险位置识别、风险分析及可视化管理。利用Revit二次开发技术,在Microsoft Visual Studio中使用C#语言连接Neo4j图数据库,完成了基于知识图谱的BCSRIM的开发。试验显示,研究提出的BCSRIM对提高施工现场的管理水平具有较高的实用价值。展开更多
文摘Key methods developed and used in the USSR and in the Russian Federation to determine the impact and friction sensitivity of energetic materials and explosives have been discussed.Experimental methodologies and instruments that underlie the assessment of their production and handling safety have been described.Studies of a large number of compounds have revealed relationships between their sensitivity parameters and structure of individual compounds and compositions.The range of change of physical and chemical characteristics for the compounds we examined covers the entire region of their existence.Theoretical methodology and equations have been formulated to estimate the impact and friction sensitivity parameters of energetic materials and to evaluate the technological safety in use.The developed methodology is characterized by high-accuracy calculations and prediction of sensitivity parameters.
文摘In this paper, the exact Bayesian limits, taking conjugate and noninformative prior distribution, and the exact fiducial limits for the mean of the lognormal distribution are presented. They can be found iteratively by one-dimension integral on a finite interval. The new algorithm is very convenient and with high accuracy. It can meet the practical engineering need excellently. However, the primitive algorithm is rather cumbersome. By the way, the very close approximate limits with a simple algorithm are derived. They can be applied immediately to engineering. Otherwise, they can also be used as a search interval to find the root of equation for the exact limits.
文摘This article demonstrates a novel approach for material nonlinear analysis.This analysis procedure eliminates tedious and lengthy step by step incremental and then iterative procedure adopted classically and gives direct results in the linear as well as in nonlinear range of the material behavior.Use of elastic moduli is eliminated.Instead,stress and strain functions are used as the material input in the analysis procedure.These stress and strain functions are directly derived from the stress-strain behavior of the material by the method of curve fitting.This way,the whole stress-strain diagram is utilized in the analysis which naturally exposes the response of structure when loading is in nonlinear range of the material behavior.It is found that it is an excellent computational procedure adopted so far for material nonlinear analysis which gives very accurate results,easy to adopt and simple in calculations.The method eliminates all types of linearity assumptions in basic derivations of equations and hence,eliminates all types of possibility of errors in the analysis procedure as well.As it is required to know stress distribution in the structural body by proper modelling and structural idealization,the proposed analysis approach can be regarded as stress-based analysis procedure.Basic problems such as uniaxial problem,beam bending,and torsion problems are solved.It is found that approach is very suitable for solving the problems of fracture mechanics.Energy release rate for plate with center crack and double cantilever beam specimen is also evaluated.The approach solves the fracture problem with relative ease in strength of material style calculations.For all problems,results are compared with the classical displacement-based liner theory.
文摘基于可视化文献计量工具CiteSpace和文献分析,利用Web of Science核心库的文献题录数据源,对2000—2022年全球抗静电高分子材料的研究热点和发展趋势进行了分析和归纳。文献记录的时空分析表明2006年开始中国的科研力量主导了该领域的发展,并在2016年后引领该领域快速增长。合作关系图谱分析表明我国虽未形成核心作者群,但研究力量局部集中。通过对关键词聚类,将抗静电高分子材料的研究内容分为材料性能、材料制备、材料应用和抗静电剂4个部分;通过中介中心性探讨了聚类之间的逻辑关系。根据关键词时区图谱揭示了抗静电高分子材料演进路径和发展趋势,关键词突现表明石墨烯及其衍生物和离子液体作为抗静电剂有望成为下一阶段的前沿热点;将不同抗静电剂复用,以发挥协同效应将成为新的技术路径。
基金Projects(50175031, 50565001) supported by the National Natural Science Foundation of China project (2003203) supported by the New Century Ten Hundred and Thousand Talent Project Special Foundation of Guangxi+1 种基金 project(0542005) supported by Guangxi Science Foundation project(205119) supported by the Key Project of Chinese Ministry of Education
文摘A four-bar linkage mechanism with links fabricated from symmetric laminates was studied. The mass matrix of the beam dement was obtained in light of the mass distribution characteristics of composite materials. The stiffness matrix of the beam element was derived from the constitutive equations of each layer and the relationship between the strain distribution and the node displacement of the beam element. The specific damping capacity of the beam element was analyzed according to the strain distribution of the beam element and the strain energy dissipation caused by vibration in each direction of each layer; and the damping coefficients were obtained according to the principle that the total energy dissipation of the beam element was equal to the work done by the equivalent damping force during a cycle of vibration, from which the damping matrix of the dynamic equations was obtained. Using the finite element method, the dynamic analytic model of the mechanism was obtained. The dynamic responses and natural frequency of the mechanism were obtained by simulation, respectively, and those of the simulation obtained by the proposed model were analyzed and compared with the results obtained by the conventional model. The work provides theoretical basis to a certain extent for the further research on nonlinear vibration characteristics and optimum design of this kind of mechanism.
文摘为了提高建筑施工安全风险管理的信息化水平,以建筑施工活动及事故风险类型为研究对象,建立施工安全知识图谱。通过知识图谱改进作业条件危险性评价法(LEC)实现安全风险的定量计算,并基于知识图谱进行风险位置识别和不安全因素分析。研究提出安全风险虚体实化理念,实现了安全风险信息在数字空间实体化表达;基于建筑信息模型(Building Information Modeling, BIM)和知识图谱技术,建立了建筑施工安全风险信息模型(Building Construction Safety Risk Information Model, BCSRIM)。该模型有效避免了传统LEC法中主观因素产生的影响,实现了建筑施工安全风险定量计算、风险位置识别、风险分析及可视化管理。利用Revit二次开发技术,在Microsoft Visual Studio中使用C#语言连接Neo4j图数据库,完成了基于知识图谱的BCSRIM的开发。试验显示,研究提出的BCSRIM对提高施工现场的管理水平具有较高的实用价值。
