In this paper, the generalized variational principle of dynamic analysis for the blast-resistant underground structures is established, and the corresponding generalized functional of elastoplastic analysis for underg...In this paper, the generalized variational principle of dynamic analysis for the blast-resistant underground structures is established, and the corresponding generalized functional of elastoplastic analysis for underground structures is derived, and the generalized variational principle of nonconservative system is given, thus the fundamental of dynamical analysis for underground structures to resist blast is proposed. Finally, for the underground cylindrical structure to resist blast, dynamical calculations are made, and compared with the test results.展开更多
In order to find out the dynamic characteristics of a steel frame structure project in the 8 degree (0.3g) area, the artificial wave, Taft wave and El Centro wave were input by using the finite element analysis softwa...In order to find out the dynamic characteristics of a steel frame structure project in the 8 degree (0.3g) area, the artificial wave, Taft wave and El Centro wave were input by using the finite element analysis software ANSYS. The dynamic time-history analysis of the structure shows the dynamic performance of the structure under the frequent earthquakes and rare earthquakes.展开更多
The equivalent stress fundamental solution for the elastoplastic dynamic plane strain problem is proposed to transform the virtual work in the third direction to the plane.Subsequently,based on Betti reciprocal theore...The equivalent stress fundamental solution for the elastoplastic dynamic plane strain problem is proposed to transform the virtual work in the third direction to the plane.Subsequently,based on Betti reciprocal theorem,by adopting the time dependent fundamental solutions in terms of displacement,traction and equivalent stress,the boundary integral equations for dynamic elastoplastic analysis for the plane strain problem are established.The establishment procedures for the displacement and the stress boundary integral equations,together with the stress equation at boundary points,are presented in details,while the standard discretization both in time and space under the frame of time domain boundary element method(TD-BEM)and the solution of the algebraic equations are also briefly stated.Two verification examples are presented from different viewpoints,for elastic and elastoplastic analysis,for 1-D and 2-D geometries,and for finite and infinite domains.The TD-BEM formulation for dynamic elastoplastic analysis is presented for the plane strain problem as an example,where the formulation is also applicable for the plane stress problem by properly transforming the elastic constants and adopting the corresponding fundamental solutions.展开更多
The seismic analysis of a rigid-framed prestressed concrete bridge in Tianjin Light Railway is performed. A 3-D dynamic finite element model of the bridge is established considering the weakening effect caused by the ...The seismic analysis of a rigid-framed prestressed concrete bridge in Tianjin Light Railway is performed. A 3-D dynamic finite element model of the bridge is established considering the weakening effect caused by the soft soil foundation. After the dynamic characteristics are calculated in terms of natural frequencies and modes, the seismic analysis is carried out using the modal response spectrum method and the time-history method, respectively. Based on the calculated results, the reasonable design values are finally suggested as the basis of the seismic design of the bridge, and meanwhile the problems encountered were also analyzed. Finally, some conclusions are drawn as: 1) Despite the superiority of rigid-framed prestressed concrete bridge, the upper and lower ends of the piers of the bridge are proved to be the crucial parts of the bridge, which are easily destroyed under designed earthquake excitations and should be carefully analyzed and designed; 2) The soft soil foundation can possibly result in rather weakening of the lateral rigidity of the rigid-framed bridge, and should be paid considerable attention; 3) The modal response spectrum method, combined with time-history method, is suggested for the seismic analysis in engineering design of the rigid-framed prestressed concrete bridge.展开更多
In this work,a new methodology is presented to mainly solve the fluid–solid interaction(FSI)equation.This methodology combines the advantages of the Newmark precise integral method(NPIM)and the dual neural network(DN...In this work,a new methodology is presented to mainly solve the fluid–solid interaction(FSI)equation.This methodology combines the advantages of the Newmark precise integral method(NPIM)and the dual neural network(DNN)method.The NPIM is employed to modify the exponential matrix and loading vector based on the DNN integral method.This involves incorporating the basic assumption of the Newmark-βmethod into the dynamic equation and eliminating the acceleration term from the dynamic equilibrium equation.As a result,the equation is reduced to a first-order linear equation system.Subsequently,the PIM is applied to integrate the system step by step within the NPIM.The DNN method is adopted to solve the inhomogeneous term through fitting the integrand and the original function with a pair of neural networks,and the integral term is solved using the Newton–Leibniz formula.Numerical examples demonstrate that the proposed methodology significantly improves computing efficiency and provides sufficient precision compared to the DNN method.This is particularly evident when analyzing large-scale structures under blast loading conditions.展开更多
文摘In this paper, the generalized variational principle of dynamic analysis for the blast-resistant underground structures is established, and the corresponding generalized functional of elastoplastic analysis for underground structures is derived, and the generalized variational principle of nonconservative system is given, thus the fundamental of dynamical analysis for underground structures to resist blast is proposed. Finally, for the underground cylindrical structure to resist blast, dynamical calculations are made, and compared with the test results.
文摘In order to find out the dynamic characteristics of a steel frame structure project in the 8 degree (0.3g) area, the artificial wave, Taft wave and El Centro wave were input by using the finite element analysis software ANSYS. The dynamic time-history analysis of the structure shows the dynamic performance of the structure under the frequent earthquakes and rare earthquakes.
基金The authors would like to acknowledge the financial support provided by Hebei Education Department(Grant QN2020135)the National Key R&D Program of China(Grants 2019YFC1511105 and 2019YFC1511104)the National Natural Science Foundation of China(Grant 51778193).
文摘The equivalent stress fundamental solution for the elastoplastic dynamic plane strain problem is proposed to transform the virtual work in the third direction to the plane.Subsequently,based on Betti reciprocal theorem,by adopting the time dependent fundamental solutions in terms of displacement,traction and equivalent stress,the boundary integral equations for dynamic elastoplastic analysis for the plane strain problem are established.The establishment procedures for the displacement and the stress boundary integral equations,together with the stress equation at boundary points,are presented in details,while the standard discretization both in time and space under the frame of time domain boundary element method(TD-BEM)and the solution of the algebraic equations are also briefly stated.Two verification examples are presented from different viewpoints,for elastic and elastoplastic analysis,for 1-D and 2-D geometries,and for finite and infinite domains.The TD-BEM formulation for dynamic elastoplastic analysis is presented for the plane strain problem as an example,where the formulation is also applicable for the plane stress problem by properly transforming the elastic constants and adopting the corresponding fundamental solutions.
文摘The seismic analysis of a rigid-framed prestressed concrete bridge in Tianjin Light Railway is performed. A 3-D dynamic finite element model of the bridge is established considering the weakening effect caused by the soft soil foundation. After the dynamic characteristics are calculated in terms of natural frequencies and modes, the seismic analysis is carried out using the modal response spectrum method and the time-history method, respectively. Based on the calculated results, the reasonable design values are finally suggested as the basis of the seismic design of the bridge, and meanwhile the problems encountered were also analyzed. Finally, some conclusions are drawn as: 1) Despite the superiority of rigid-framed prestressed concrete bridge, the upper and lower ends of the piers of the bridge are proved to be the crucial parts of the bridge, which are easily destroyed under designed earthquake excitations and should be carefully analyzed and designed; 2) The soft soil foundation can possibly result in rather weakening of the lateral rigidity of the rigid-framed bridge, and should be paid considerable attention; 3) The modal response spectrum method, combined with time-history method, is suggested for the seismic analysis in engineering design of the rigid-framed prestressed concrete bridge.
基金supported by the National Natural Science Foundation of China(Grant Nos.12072288,U2241274,and 12272319).
文摘In this work,a new methodology is presented to mainly solve the fluid–solid interaction(FSI)equation.This methodology combines the advantages of the Newmark precise integral method(NPIM)and the dual neural network(DNN)method.The NPIM is employed to modify the exponential matrix and loading vector based on the DNN integral method.This involves incorporating the basic assumption of the Newmark-βmethod into the dynamic equation and eliminating the acceleration term from the dynamic equilibrium equation.As a result,the equation is reduced to a first-order linear equation system.Subsequently,the PIM is applied to integrate the system step by step within the NPIM.The DNN method is adopted to solve the inhomogeneous term through fitting the integrand and the original function with a pair of neural networks,and the integral term is solved using the Newton–Leibniz formula.Numerical examples demonstrate that the proposed methodology significantly improves computing efficiency and provides sufficient precision compared to the DNN method.This is particularly evident when analyzing large-scale structures under blast loading conditions.
