Molecular dynamics simulations are carried out to investigate the mechanisms of low-temperature impact toughness of the ultrafine grain structure steel. The simulation results suggest that the sliding of the {001 }/{ ...Molecular dynamics simulations are carried out to investigate the mechanisms of low-temperature impact toughness of the ultrafine grain structure steel. The simulation results suggest that the sliding of the {001 }/{ 110} type and { 110}/{ 111 } type grain boundary can improve the impact toughness. Then, the mechanism of grain boundary sliding is studied and it is found that the motion of dislocations along the grain boundary is the underlying cause of the grain boundary sliding. Finally, the sliding of the grain boundary is analyzed from the standpoint of the energy. We conclude that the measures which can increase the quantity of the {001}/{110} type and {110}/{ 111} type grain boundary and elongate the free gliding distance of dislocations along these grain boundaries will improve the low-temperature impact toughness of the ultrafine grain structure steel.展开更多
The primary objective of the present literature review is to provide a constructive and systematical discussion based on the relevant development,unsolved issues,gaps,and misconceptions in the literature regarding the...The primary objective of the present literature review is to provide a constructive and systematical discussion based on the relevant development,unsolved issues,gaps,and misconceptions in the literature regarding the fields of study that are building blocks of artificial intelligence-aided life extension assessment for offshore wind turbine support structures.The present review aims to set up the needed guidelines to develop a multi-disciplinary framework for life extension management and certification of the support structures for offshore wind turbines using artificial intelligence.The main focus of the literature review centres around the intelligent risk-based life extension management of offshore wind turbine support structures.In this regard,big data analytics,advanced signal processing techniques,supervised and unsupervised machine learning methods are discussed within the structural health monitoring and condition-based maintenance planning,the development of digital twins.Furthermore,the present review discusses the critical failure mechanisms affecting the structural condition,such as high-cycle fatigue,low-cycle fatigue,fracture,ultimate strength,and corrosion,considering deterministic and probabilistic approaches.展开更多
The objective of this work is to analyse fatigue reliability of deck structures subjected to correlated crack growth.The stress intensity factors of the correlated cracks are obtained by finite element analysis and ba...The objective of this work is to analyse fatigue reliability of deck structures subjected to correlated crack growth.The stress intensity factors of the correlated cracks are obtained by finite element analysis and based on which the geometry correction functions are derived.The Monte Carlo simulations are applied to predict the statistical descriptors of correlated cracks based on the Paris-Erdogan equation.A probabilistic model of crack growth as a function of time is used to analyse the fatigue reliability of deck structures accounting for the crack propagation correlation.A deck structure is modelled as a series system of stiffened panels,where a stiffened panel is regarded as a parallel system composed of plates and are longitudinal.It has been proven that the method developed here can be conveniently applied to perform the fatigue reliability assessment of structures subjected to correlated crack growth.展开更多
Lug joints are preferred joineries for transferring heavy loads to parent components in aerospace vehicles.They experience corrosion due to environmental conditions,improper surface finishes and rubbing displacement b...Lug joints are preferred joineries for transferring heavy loads to parent components in aerospace vehicles.They experience corrosion due to environmental conditions,improper surface finishes and rubbing displacement between the pin and lug-hole.This causes damage of different sizes and shapes near the lug-hole.Stiffness degradation due to corrosion-induced damage is modelled as a through-pit at one of the identified critical locations through stress analysis.The effect of this pit on fatigue crack initiation life is estimated.Lug-hole is pre-stressed by cold-working and the benefits of inducing plastic wake on the intended performance of the lug joint during the damages due to corrosion are brought out and compared with non-cold-worked lug-hole.Numerical analysis is performed on this lug joint with pressfit.The results obtained highlight the benefits of cold-working and the methodology can be extended to damage growth and analyse the effect of surface treatments for better structural integrity of components of aerospace vehicles.展开更多
为探究不同反应条件对MOFs微观结构和宏观性能的影响,在不同反应条件下,以硫酸铜(CuSO_(4)·5H_(2)O)和6-(吡啶-3′-基)间苯二甲酸(H_(2)L)为材料,制备了2种金属有机框架材料(MOFs){[Cu_(2)(L)_(2)·C _(2) H _(3) N]}n(1)和{[C...为探究不同反应条件对MOFs微观结构和宏观性能的影响,在不同反应条件下,以硫酸铜(CuSO_(4)·5H_(2)O)和6-(吡啶-3′-基)间苯二甲酸(H_(2)L)为材料,制备了2种金属有机框架材料(MOFs){[Cu_(2)(L)_(2)·C _(2) H _(3) N]}n(1)和{[Cu(HL)_(2)]}n(2),并对合成的金属有机框架材料1和2进行了结构分析、TGA和FTIR表征以及对染料的吸附性能研究。单晶衍射数据分析表明:配合物1和2都属单斜晶系,P 21/c空间群。配合物1是一种基于双核轮桨次级构筑单元[Cu_(2)(COO)_(4)]构筑的三维紧密堆积化合物,配合物2由于配体部分质子化,结构中存在氢键[O_(3)—H…O_(4)],将二维层状网络结构连接成三维结构。配合物1是rtl拓扑类型的网络结构,拓扑符号为(42.610.83);配合物2是sql拓扑类型的网络结构,拓扑符号为(4^(4).6^(2))。2种配合物在相同时间间隔下对不同染料降解性能表明配合物2对水溶液中的孔雀石绿具有一定的化学吸附降解能力。展开更多
为解决当前在钢结构建筑信息模型(building information modeling,BIM)与结构分析模型之间进行数据转换时存在的关键技术问题,本文在分析工业基础类(industry foundation classes,IFC)标准表达方法的基础上,以ABAQUS为结构分析平台,开...为解决当前在钢结构建筑信息模型(building information modeling,BIM)与结构分析模型之间进行数据转换时存在的关键技术问题,本文在分析工业基础类(industry foundation classes,IFC)标准表达方法的基础上,以ABAQUS为结构分析平台,开发了钢结构BIM模型数据转换算法,运用C#语言和Xbim工具包,实现了结构构件信息提取、构件空间位置调整和分析数据自动添加,并形成了相应的转换软件;通过钢框架结构实例分析验证了该软件的可靠性和准确性,并将其应用于安阳市游客集散中心的BIM模型转换和结构分析。结果表明,所开发的算法和软件解决了生成的结构分析模型节点不连接和人工添加分析数据工作量大等问题,实现了BIM中的钢结构设计模型或深化设计模型向ABAQUS结构分析模型数据的准确转换。与传统的在ABAQUS中直接建立结构分析模型相比,本文提出的方法能大大提高复杂钢结构的结构分析建模速度和效率。展开更多
为综合评估战后建筑结构的毁伤等级,针对爆炸作用下典型地面建筑,即含填充墙钢筋混凝土(reinforced concrete,RC)框架结构,提出了损伤破坏和倒塌的高精度数值仿真分析方法,并通过RC结构爆炸试验、倒塌事故和砌体墙爆炸试验进行了充分验...为综合评估战后建筑结构的毁伤等级,针对爆炸作用下典型地面建筑,即含填充墙钢筋混凝土(reinforced concrete,RC)框架结构,提出了损伤破坏和倒塌的高精度数值仿真分析方法,并通过RC结构爆炸试验、倒塌事故和砌体墙爆炸试验进行了充分验证;开展了典型3层原型RC框架结构在不同爆炸当量(25~200 kg TNT)下的内爆炸数值仿真,定量分析了爆炸冲击波在建筑结构内部的传播、结构损伤破坏和墙体飞散等。爆炸作用下建筑结构的高效毁伤评估流程为:结合镜像爆源和非线性叠加原理确定内爆炸荷载,基于等效单自由度方法评估梁、板、柱及墙体构件的毁伤等级,引入构件重要性系数加权确定房间毁伤等级,考虑房间功能及位置重要性评估整体结构的毁伤等级。高精度数值仿真分析与毁伤评估方法计算的典型RC框架结构的整体毁伤等级一致,即在25、100和200 kg TNT爆炸下RC结构分别呈现轻度、中度和重度毁伤,毁伤评估方法可缩短99%以上的计算耗时,兼具可靠性与时效性。展开更多
文摘Molecular dynamics simulations are carried out to investigate the mechanisms of low-temperature impact toughness of the ultrafine grain structure steel. The simulation results suggest that the sliding of the {001 }/{ 110} type and { 110}/{ 111 } type grain boundary can improve the impact toughness. Then, the mechanism of grain boundary sliding is studied and it is found that the motion of dislocations along the grain boundary is the underlying cause of the grain boundary sliding. Finally, the sliding of the grain boundary is analyzed from the standpoint of the energy. We conclude that the measures which can increase the quantity of the {001}/{110} type and {110}/{ 111} type grain boundary and elongate the free gliding distance of dislocations along these grain boundaries will improve the low-temperature impact toughness of the ultrafine grain structure steel.
文摘The primary objective of the present literature review is to provide a constructive and systematical discussion based on the relevant development,unsolved issues,gaps,and misconceptions in the literature regarding the fields of study that are building blocks of artificial intelligence-aided life extension assessment for offshore wind turbine support structures.The present review aims to set up the needed guidelines to develop a multi-disciplinary framework for life extension management and certification of the support structures for offshore wind turbines using artificial intelligence.The main focus of the literature review centres around the intelligent risk-based life extension management of offshore wind turbine support structures.In this regard,big data analytics,advanced signal processing techniques,supervised and unsupervised machine learning methods are discussed within the structural health monitoring and condition-based maintenance planning,the development of digital twins.Furthermore,the present review discusses the critical failure mechanisms affecting the structural condition,such as high-cycle fatigue,low-cycle fatigue,fracture,ultimate strength,and corrosion,considering deterministic and probabilistic approaches.
基金Supported by China Scholarship Council under Grant No.2008110133
文摘The objective of this work is to analyse fatigue reliability of deck structures subjected to correlated crack growth.The stress intensity factors of the correlated cracks are obtained by finite element analysis and based on which the geometry correction functions are derived.The Monte Carlo simulations are applied to predict the statistical descriptors of correlated cracks based on the Paris-Erdogan equation.A probabilistic model of crack growth as a function of time is used to analyse the fatigue reliability of deck structures accounting for the crack propagation correlation.A deck structure is modelled as a series system of stiffened panels,where a stiffened panel is regarded as a parallel system composed of plates and are longitudinal.It has been proven that the method developed here can be conveniently applied to perform the fatigue reliability assessment of structures subjected to correlated crack growth.
文摘Lug joints are preferred joineries for transferring heavy loads to parent components in aerospace vehicles.They experience corrosion due to environmental conditions,improper surface finishes and rubbing displacement between the pin and lug-hole.This causes damage of different sizes and shapes near the lug-hole.Stiffness degradation due to corrosion-induced damage is modelled as a through-pit at one of the identified critical locations through stress analysis.The effect of this pit on fatigue crack initiation life is estimated.Lug-hole is pre-stressed by cold-working and the benefits of inducing plastic wake on the intended performance of the lug joint during the damages due to corrosion are brought out and compared with non-cold-worked lug-hole.Numerical analysis is performed on this lug joint with pressfit.The results obtained highlight the benefits of cold-working and the methodology can be extended to damage growth and analyse the effect of surface treatments for better structural integrity of components of aerospace vehicles.
文摘为解决当前在钢结构建筑信息模型(building information modeling,BIM)与结构分析模型之间进行数据转换时存在的关键技术问题,本文在分析工业基础类(industry foundation classes,IFC)标准表达方法的基础上,以ABAQUS为结构分析平台,开发了钢结构BIM模型数据转换算法,运用C#语言和Xbim工具包,实现了结构构件信息提取、构件空间位置调整和分析数据自动添加,并形成了相应的转换软件;通过钢框架结构实例分析验证了该软件的可靠性和准确性,并将其应用于安阳市游客集散中心的BIM模型转换和结构分析。结果表明,所开发的算法和软件解决了生成的结构分析模型节点不连接和人工添加分析数据工作量大等问题,实现了BIM中的钢结构设计模型或深化设计模型向ABAQUS结构分析模型数据的准确转换。与传统的在ABAQUS中直接建立结构分析模型相比,本文提出的方法能大大提高复杂钢结构的结构分析建模速度和效率。
文摘为综合评估战后建筑结构的毁伤等级,针对爆炸作用下典型地面建筑,即含填充墙钢筋混凝土(reinforced concrete,RC)框架结构,提出了损伤破坏和倒塌的高精度数值仿真分析方法,并通过RC结构爆炸试验、倒塌事故和砌体墙爆炸试验进行了充分验证;开展了典型3层原型RC框架结构在不同爆炸当量(25~200 kg TNT)下的内爆炸数值仿真,定量分析了爆炸冲击波在建筑结构内部的传播、结构损伤破坏和墙体飞散等。爆炸作用下建筑结构的高效毁伤评估流程为:结合镜像爆源和非线性叠加原理确定内爆炸荷载,基于等效单自由度方法评估梁、板、柱及墙体构件的毁伤等级,引入构件重要性系数加权确定房间毁伤等级,考虑房间功能及位置重要性评估整体结构的毁伤等级。高精度数值仿真分析与毁伤评估方法计算的典型RC框架结构的整体毁伤等级一致,即在25、100和200 kg TNT爆炸下RC结构分别呈现轻度、中度和重度毁伤,毁伤评估方法可缩短99%以上的计算耗时,兼具可靠性与时效性。
