Some properties of the pseudo umbilical surface M in R 4 are discussed and thus the lower for the tolal mean curvature of M is estimated. On the basis of the estimation and by using the Gauss map of M...Some properties of the pseudo umbilical surface M in R 4 are discussed and thus the lower for the tolal mean curvature of M is estimated. On the basis of the estimation and by using the Gauss map of M , a sufficient condition is given for M as a flat torus in R 4 .展开更多
For the purpose of carrying out the large deformation finite element analysis of spatial curved beams,the total Lagrangian（TL）and the updated Lagrangian（UL）incremental formulations for arbitrary spatial curved bea...For the purpose of carrying out the large deformation finite element analysis of spatial curved beams,the total Lagrangian（TL）and the updated Lagrangian（UL）incremental formulations for arbitrary spatial curved beam elements are established with displacement vector interpolation,which is improved from component interpolation of the straight beam displacement.A strategy of replacing the actual curve with the isoparametric curve is used to expand the applications of the UL formulation.The examples indicate that the process of establishing the curved beam element is correct,and the accuracy with the curved beam element is obviously higher than that with the straight beam element.Generally,the same level of computational accuracy can be achieved with 1/5 as many curved beam elements as otherwise with straight beam elements.展开更多
文摘Some properties of the pseudo umbilical surface M in R 4 are discussed and thus the lower for the tolal mean curvature of M is estimated. On the basis of the estimation and by using the Gauss map of M , a sufficient condition is given for M as a flat torus in R 4 .
基金The Major Research Plan of the National Natural Science Foundation of China(No.90715021)
文摘For the purpose of carrying out the large deformation finite element analysis of spatial curved beams,the total Lagrangian（TL）and the updated Lagrangian（UL）incremental formulations for arbitrary spatial curved beam elements are established with displacement vector interpolation,which is improved from component interpolation of the straight beam displacement.A strategy of replacing the actual curve with the isoparametric curve is used to expand the applications of the UL formulation.The examples indicate that the process of establishing the curved beam element is correct,and the accuracy with the curved beam element is obviously higher than that with the straight beam element.Generally,the same level of computational accuracy can be achieved with 1/5 as many curved beam elements as otherwise with straight beam elements.
