scholarly journals Finite Element Formulation for the Finite Strain Thermo-Elasto-Plastic Solid using Exponential Mapping Algorithm : Model and Time Integration Scheme

2004 ◽  
Vol 8 (2) ◽  
pp. 19-25
Author(s):  
Makoto Tanabe ◽  
Hajime Wakui ◽  
Nobuyuki Matsumoto

Abstract This paper describes a finite element formulation to solve for the combined dynamic behavior of Shinkansen (bullet train) vehicles, irregular rails, and bridges. A mechanical model for interactions between a wheel and an irregular rail is discussed. The bridge is modeled by use of various finite elements. An efficient numerical method, based on modal analysis and exact time integration, is described for solving the nonlinear equations of motion of the Shinkansen vehicle and bridge. The convergence of the exact time integration scheme is discussed and compared with a previous numerical time integration scheme. A finite element computer program has been developed to analyze the dynamic response of Shinkansen vehicles operating at high speed over irregular rails and a bridge. Numerical examples are presented to demonstrate the effectiveness and validity of the present approach.


1981 ◽  
Vol 103 (4) ◽  
pp. 657-664 ◽  
Author(s):  
H. U. Akay ◽  
A. Ecer

Analysis of transonic flow through a cascade of airfoils is investigated using the finite element method. Development of a computational grid suitable for complex flow structures and different types of boundary conditions is presented. An efficient pseudo-time integration scheme is developed for the solution of equations. Modeling of the shock and the convergence characteristics of the developed scheme are discussed. Numerical results include a 45 deg staggered cascade of NACA 0012 airfoils with inlet flow Mach number of 0.8 and angles of attack 1, 0, and −1 deg.


Author(s):  
V. Chawla ◽  
T. A. Laursen

Abstract 1D impact between two identical bars is modeled as a simple spring-mass system as would be generated by a finite element discretization. Some commonly used time integrators are applied to the system to demonstrate defects in the numerical solution as compared to the exact analytical solution. Using energy conservation as the criterion for stability, a new time integration scheme is proposed that imposes a persistency condition for dynamic contact. Finite element simulation with Lagrange multipliers for enforcing the contact constraints shows exact energy and momentum conservation.


Author(s):  
Genady Shagal ◽  
Shaker A. Meguid

Abstract The coupled dynamic response of two cooperating robots handling two flexible payloads for the purpose of fixtureless assembly and manufacturing is treated using a new algorithm. In this algorithm, the equations describing the dynamics of the system are obtained using Lagrange’s method for the rigid robot links and the finite element method for the flexible payloads. A new time integration scheme is developed to treat the coupled equations of motion of the rigid links for a given displacement of the flexible payloads. The finite element equations of the flexible payloads are then treated using an implicit approach. The new algorithm was verified using simplified examples and was later used to examine the dynamic response of two cooperating robot arms manipulating flexible payloads which are typical of the automotive industry.


Author(s):  
Chetan Kumar Hirwani ◽  
Subrata Kumar Panda ◽  
Siba Sankar Mahapatra ◽  
Sanjib Kumar Mandal ◽  
Apurba Kumar De

In the present article, the dynamic behaviour of the delaminated composite plate subjected to blast loading has been investigated. For the investigation, a general finite element model using higher-order mid-plane kinematics has been developed. The model has been discretised using nine noded isoparametric Lagrangian elements having nine degrees of freedom at each node. The continuity in the laminated and delaminated section has been established using the intermittent continuity condition. The final governing equation has been solved by applying Newmark’s time integration scheme in conjunction with finite element steps. Further, the said responses have been evaluated by developing an in-house MATLAB code based on the proposed model. In order to illustrate the consistency and accuracy of the present model, convergence and comparison study has been conducted i.e. the responses are evaluated for different mesh sizes and compared them with those of responses of earlier published literature. Finally, various examples have been solved to illustrate the influence of the size and position of debonding, side to thickness ratio, aspect ratio and end condition on the dynamic response of composite structure and discussed in detail.


2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Yingbin Chai ◽  
Yongou Zhang

In this work, the edge-based smoothed finite element method (ES-FEM) is incorporated with the Bathe time integration scheme to solve the transient wave propagation problems. The edge-based gradient smoothing technique (GST) can properly soften the “overly soft” system matrices from the standard finite element approach; then, the spatial numerical dispersion error of the calculated solutions for wave problems can be significantly reduced. To effectively solve the transient wave propagation problems, the Bathe time integration scheme is employed to perform the involved time integration. Due to the appropriate “numerical dissipation effects” from the Bathe time integration method, the spurious oscillations in the relatively large wave numbers (high frequencies) can be effectively suppressed; then, the temporal numerical dispersion error in the calculated solutions can also be notably controlled. A number of supporting numerical examples are considered to examine the capabilities of the present approach. The numerical results show that ES-FEM works very well with the Bathe time integration technique, and much more numerical solutions can be reached for solving transient wave propagation problems compared to the standard FEM.


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