The bending stresses of top tensioned riser(TTR) under combined excitations of currents,random waves and vessel motions are presented in this paper,and the effect of the internal flowing fluid on the riser stresses is...The bending stresses of top tensioned riser(TTR) under combined excitations of currents,random waves and vessel motions are presented in this paper,and the effect of the internal flowing fluid on the riser stresses is also considered.The computation programs which are used to solve the differential equations in the time domain are compiled and the principal factors of concern including the angular movements at the upper and lower ends of the riser,lateral displacements and bending stresses are presented.Then the effects of current velocity,random wave,top tension,vessel mean offset,low frequency motion and internal flow velocity on the bending stresses of the riser are analyzed in detail.展开更多
A new analytical method for springback of small curvature plane bending is addressed with unloading rule of classical elastic-plastic theory and principle of strain superposition.We start from strain analysis of plane...A new analytical method for springback of small curvature plane bending is addressed with unloading rule of classical elastic-plastic theory and principle of strain superposition.We start from strain analysis of plane bending which has initial curvature,and the theoretic derivation is on the widely applicable basic hypotheses.The results are unified to geometry constraint equations and springback equation of plane bending,which can be evolved to straight beam plane bending and pure bending.The expanding and setting round process is one of the situations of plane bending,which is a bend-stretching process of plane curved beam.In the present study,springback equation of plane bending is used to analyze the expanding and setting round process,and the results agree with the experimental data.With a reasonable prediction accuracy,this new analytical method for springback of plane bending can meet the needs of applications in engineering.展开更多
基金supported by the High Technology Research and Development Program of China (863 Program, Grant Nos SQ2009AA09Z3487852 and 2007AA09Z313)
文摘The bending stresses of top tensioned riser(TTR) under combined excitations of currents,random waves and vessel motions are presented in this paper,and the effect of the internal flowing fluid on the riser stresses is also considered.The computation programs which are used to solve the differential equations in the time domain are compiled and the principal factors of concern including the angular movements at the upper and lower ends of the riser,lateral displacements and bending stresses are presented.Then the effects of current velocity,random wave,top tension,vessel mean offset,low frequency motion and internal flow velocity on the bending stresses of the riser are analyzed in detail.
基金supported by the National Natural Science Foundation of China(Grant No.50805126)the Natural Science Foundation of Hebei Province(Grant No.E2009000389)
文摘A new analytical method for springback of small curvature plane bending is addressed with unloading rule of classical elastic-plastic theory and principle of strain superposition.We start from strain analysis of plane bending which has initial curvature,and the theoretic derivation is on the widely applicable basic hypotheses.The results are unified to geometry constraint equations and springback equation of plane bending,which can be evolved to straight beam plane bending and pure bending.The expanding and setting round process is one of the situations of plane bending,which is a bend-stretching process of plane curved beam.In the present study,springback equation of plane bending is used to analyze the expanding and setting round process,and the results agree with the experimental data.With a reasonable prediction accuracy,this new analytical method for springback of plane bending can meet the needs of applications in engineering.
