Isogeometric Scaled Boundary Finite Element Method And Its Application In Tunnel Structure

With the rapid development of high-speed railway and urban rail transit,tunnel structure is widely applied in engineering.However,for solving the space-time coupled viscoelastic problem within the tunnel structure,the calculation accuracy and efficiency of traditional numerical method is still difficult to meet the actual requirement.In this paper,a new high-precision,high-efficiency numerical calculation method is developed based on the isogeometric scaled boundary finite element method and the temporally piecewise adaptive algorithm and the proposed method is applied to the preliminary analysis of the creep displacement of tunnel structure.In this paper,the numerical method mentioned for solving the creep displacement of viscoelastic materials involves the discretization of time domain and space domain in the implementation process.In the time domain,temporally piecewise adaptive algorithm is adopted to convert the space-time coupled nonlinear viscoelastic problem into a series of linear elasticity space problems,and the specified calculation accuracy is obtained within the corresponding time step to achieve self-adaptation calculation.In the space domain,the isogeometric scaled boundary finite element method is used to achieve the unification of CAD and CAE data,only need to discrete the boundary of the solution domain,inherited the advantages of the scaled boundary element method in the solution of the unbounded domain and stress singular problems,and the accuracy and efficiency of the solution is improved further more.The research content of this article mainly includes the following aspects:1.The numerical research is applied for verifying the properties of non-uniform rational B-spline(NURBS)in isogeometric analysis,the numerical model of plane curve-fitting and the node insertion encryption refinement have been completed,which provides a theoretical basis for the follow-up work.2.The solving process of the isogeometric scaled boundary finite element method equations for elastic problems is derived.The numerical examples are used to verify the accuracy of the proposed model,and the author compared with the traditional proportional boundary element method in terms of calculation accuracy and efficiency.3.Combining temporally piecewise adaptive algorithm and isogeometric scaled boundary finite element method,a new numerical method for solving viscoelastic problems is proposed.The numerical solution of the viscoelastic problem is derived by using piecewise adaptive algorithm isogeometric scaled boundary finite element method and correctness of the proposed method is verified by numerical examples.4.By using the established numerical calculation method,a preliminary application was made in the tunnel structure analysis.Comparison of numerical results,the feasibility and effectiveness of the proposed method is verified,which provides a new idea for solving the creep displacement of tunnel structure.According to the results of numerical example analysis,the calculation accuracy and efficiency of proposed numerical method for viscoelastic creep problem is superior to the traditional method,and it has good practical engineering application value.Based on the research work of this paper,we can do further research on related issues.