The yield behavior of metallic glasses was studied. Three yield criteria, including von Mises yield criterion, Mohr-Coulomb yield criterion and the unified yield criterion were used to describe the yield phenomena of ...The yield behavior of metallic glasses was studied. Three yield criteria, including von Mises yield criterion, Mohr-Coulomb yield criterion and the unified yield criterion were used to describe the yield phenomena of the metallic glasses. Two classes of the experimental data were chosen to draw the yield loci using the unified yield criterion. It is shown that the unified yield criterion can be used to describe the yield behavior of the metallic glasses no matter whether the metallic glasses show strength- different effect or non-strength-different effect. Almost all the widely accepted yield criteria are the subsets of the unified yield criterion if the intermediate principle stress and/or the intermediate principle shear stress are not considered at all.展开更多
In a typical tension leg platform (TLP) design,the top tension factor (TTF),measuring the top tension of a top tensioned riser (TTR) relative to its submerged weight in water,is one of the most important design parame...In a typical tension leg platform (TLP) design,the top tension factor (TTF),measuring the top tension of a top tensioned riser (TTR) relative to its submerged weight in water,is one of the most important design parameters that has to be specified properly. While a very small TTF may lead to excessive vortex induced vibration (VIV),clashing issues and possible compression close to seafloor,an unnecessarily high TTF may translate into excessive riser cost and vessel payload,and even has impacts on the TLP sizing and design in general. In the process of a production TTR design,it is found that its outer casing can be subjected to compression in a worst-case scenario with some extreme metocean and hardware conditions. The present paper shows how finite element analysis (FEA) models using beam elements and two different software packages (Flexcom and ABAQUS) are constructed to simulate the TTR properly,and especially the pipe-in-pipe effects. An ABAQUS model with hybrid elements (beam elements globally + shell elements locally) can be used to investigate how the outer casing behaves under compression. It is shown for the specified TTR design,even with its outer casing being under some local compression in the worst-case scenario,dynamic buckling would not occur;therefore the TTR design is adequate.展开更多
基金Projects(51011120053, 50823006, 50825102) supported by the National Natural Science Foundation of China
文摘The yield behavior of metallic glasses was studied. Three yield criteria, including von Mises yield criterion, Mohr-Coulomb yield criterion and the unified yield criterion were used to describe the yield phenomena of the metallic glasses. Two classes of the experimental data were chosen to draw the yield loci using the unified yield criterion. It is shown that the unified yield criterion can be used to describe the yield behavior of the metallic glasses no matter whether the metallic glasses show strength- different effect or non-strength-different effect. Almost all the widely accepted yield criteria are the subsets of the unified yield criterion if the intermediate principle stress and/or the intermediate principle shear stress are not considered at all.
文摘In a typical tension leg platform (TLP) design,the top tension factor (TTF),measuring the top tension of a top tensioned riser (TTR) relative to its submerged weight in water,is one of the most important design parameters that has to be specified properly. While a very small TTF may lead to excessive vortex induced vibration (VIV),clashing issues and possible compression close to seafloor,an unnecessarily high TTF may translate into excessive riser cost and vessel payload,and even has impacts on the TLP sizing and design in general. In the process of a production TTR design,it is found that its outer casing can be subjected to compression in a worst-case scenario with some extreme metocean and hardware conditions. The present paper shows how finite element analysis (FEA) models using beam elements and two different software packages (Flexcom and ABAQUS) are constructed to simulate the TTR properly,and especially the pipe-in-pipe effects. An ABAQUS model with hybrid elements (beam elements globally + shell elements locally) can be used to investigate how the outer casing behaves under compression. It is shown for the specified TTR design,even with its outer casing being under some local compression in the worst-case scenario,dynamic buckling would not occur;therefore the TTR design is adequate.
