A computation framework for brittle fracture which incorporates weakest link statistics and a microme- chanics model reflecting reflecting local damage of the material is described.The Weibull stress W emerges as a ...A computation framework for brittle fracture which incorporates weakest link statistics and a microme- chanics model reflecting reflecting local damage of the material is described.The Weibull stress W emerges as a probabilistic fracture parameter to define the condition leading material failure. Unstable crack propa- gation occurs at a critical value of W which may be attained paior to or following some amount of duc- tile crack extension. A realistic model of ductile crack growth using the computation cell methodology is used to define the evolution of near tip stress fields during crack extension. An application of proposed framework to predict the measured geometry and ductile tearing effects on the statistical distributio of fracture toughness for the pipe line steel welded joint is described.展开更多
Why are pieces of spaghetti generally broken into three to ten segments instead of two as one thinks?How can one obtain the desired number of fracture segments?To answer those questions,the fracture dynamics of a stra...Why are pieces of spaghetti generally broken into three to ten segments instead of two as one thinks?How can one obtain the desired number of fracture segments?To answer those questions,the fracture dynamics of a strand of spaghetti is modelled by elastic rod and numerically investigated by using finiteelement software ABAQUS.By data fitting,two relations are obtained:the number of fracture segments in terms of rod diameter-length ratio and fracture limit curvature with the rod diameter.Results reveal that when the length is constant,the larger the diameter and/or the smaller the diameter-length ratio D/L,the smaller the limit curvature;and the larger the diameter-length ratio D/L,the fewer the number of fractured segments.The relevant formulations can be used to obtain the desired number of broken segments of spaghetti by changing the diameter-to-length ratio.展开更多
Recently,there have been the increase of ship size and the development of oil and gas in arctic region.These trends have led to the requirements such as high strength,good toughness at low temperature and good weldabi...Recently,there have been the increase of ship size and the development of oil and gas in arctic region.These trends have led to the requirements such as high strength,good toughness at low temperature and good weldability.The high performance structural steels for shipbuilding and arctic offshore structure have been developed by our own micro-alloying and TMCP technologies.M-A constituent was precisely controlled in the both HAZ and base metal to get high toughness at low temperature.Also,the grain growth of austenite at HAZ was effectively suppressed by thermally stable TiN particles,leading to a good HAZ toughness.On the other hand,there has been the key issue of crack arrestability in large size container ship.The effect of joint design on crack arrestability was investigated to prevent a catastrophic failure along the block joint of hatch side coaming.A brittle crack arrest technique was developed without block joint shift,using an arrest weld in the end of hatch side coaming weld line.展开更多
文摘A computation framework for brittle fracture which incorporates weakest link statistics and a microme- chanics model reflecting reflecting local damage of the material is described.The Weibull stress W emerges as a probabilistic fracture parameter to define the condition leading material failure. Unstable crack propa- gation occurs at a critical value of W which may be attained paior to or following some amount of duc- tile crack extension. A realistic model of ductile crack growth using the computation cell methodology is used to define the evolution of near tip stress fields during crack extension. An application of proposed framework to predict the measured geometry and ductile tearing effects on the statistical distributio of fracture toughness for the pipe line steel welded joint is described.
基金supported by Xi’an University of Architecture and Technology(Grant No.002/2040221134).
文摘Why are pieces of spaghetti generally broken into three to ten segments instead of two as one thinks?How can one obtain the desired number of fracture segments?To answer those questions,the fracture dynamics of a strand of spaghetti is modelled by elastic rod and numerically investigated by using finiteelement software ABAQUS.By data fitting,two relations are obtained:the number of fracture segments in terms of rod diameter-length ratio and fracture limit curvature with the rod diameter.Results reveal that when the length is constant,the larger the diameter and/or the smaller the diameter-length ratio D/L,the smaller the limit curvature;and the larger the diameter-length ratio D/L,the fewer the number of fractured segments.The relevant formulations can be used to obtain the desired number of broken segments of spaghetti by changing the diameter-to-length ratio.
文摘Recently,there have been the increase of ship size and the development of oil and gas in arctic region.These trends have led to the requirements such as high strength,good toughness at low temperature and good weldability.The high performance structural steels for shipbuilding and arctic offshore structure have been developed by our own micro-alloying and TMCP technologies.M-A constituent was precisely controlled in the both HAZ and base metal to get high toughness at low temperature.Also,the grain growth of austenite at HAZ was effectively suppressed by thermally stable TiN particles,leading to a good HAZ toughness.On the other hand,there has been the key issue of crack arrestability in large size container ship.The effect of joint design on crack arrestability was investigated to prevent a catastrophic failure along the block joint of hatch side coaming.A brittle crack arrest technique was developed without block joint shift,using an arrest weld in the end of hatch side coaming weld line.
