Vector Form Intrinsic Finite Element Method for Analysis of Train–Bridge Interaction Problems Considering The Coach-Coupler Effect

2019 ◽  
Vol 19 (02) ◽  
pp. 1950014 ◽  
Author(s):  
Y. F. Duan ◽  
S. M. Wang ◽  
J. D. Yau
Keyword(s):  
Finite Element ◽  
Resonance Phenomenon ◽  
Vector Form ◽  
Beam Elements ◽  
Suspension Systems ◽  
Stiffness Matrices ◽  
Internal Forces ◽  
Dual Resonance ◽  
Multi Body ◽  
Intense Vibration

In this paper, the vector form intrinsic finite element (VFIFE) method is presented for analysis the train–bridge systems considering the coach-coupler effect. The bridge is discretized into a group of mass particles linked by massless beam elements and the multi-body coach with suspension systems is simulated as a set of mass particles connected by parallel spring-dashpot units. Then the equation of motion of each mass particle is solved individually and the internal forces induced by pure deformations in the massless beam elements are calculated by a fictitious reverse motion method, in which the structural stiffness matrices need not be updated or factorized. Though the vector-form equations resulting from the VFIFE method cannot be used to compute the structural frequencies by the eigenvalue approach, this study proposes a numerical free vibration test to identify the bridge frequencies for evaluating the bridge damping. Numerical verifications demonstrate that the present VFIFE method performs as accurately as previous numerical ones. The results show that the couplers play an energy-dissipating role in reducing the car bodies’ response due to the bridge-induced resonance, but not in their response due to the train-induced resonance because of the bridge’s intense vibration. Meanwhile, a dual-resonance phenomenon in the train–bridge system occurs when the coach-coupler effect is considered in the vehicle model.

scholarly journals Vector form Intrinsic Finite Element Based Approach to Simulate Crack Propagation

2017 ◽  
Vol 33 (6) ◽  
pp. 797-812 ◽  
Author(s):  
Y. F. Duan ◽  
S. M. Wang ◽  
R. Z. Wang ◽  
C. Y. Wang ◽  
E. C. Ting
Keyword(s):  
Finite Element ◽  
Crack Propagation ◽  
Integral Method ◽  
Crack Tip ◽  
Cohesive Crack ◽  
Vector Form ◽  
Mass Particle ◽  
Integral Methods ◽  
Stiffness Matrices ◽  
Cohesive Crack Propagation

AbstractThis paper presents a new approach to simulate the propagation of elastic and cohesive cracks under mode-I loading based on the vector form intrinsic finite element method. The proposed approach can handle crack propagation without requiring global stiffness matrices and extra weak stiffness elements. The structure is simulated by mass particles whose motions are governed by the Newton's second law. Elastic and cohesive crack propagation are simulated by proposed VFIFE-J-integral and VFIFE-FCM methods, respectively. The VFIFE-J-integral method is based on vector form intrinsic finite element (VFIFE) and J-integral methods to calculate the stress intensity factors at the crack tips, and the VFIFE-FCM method combines VFIFE and fictitious crack models (FCM). When the stress state at the crack tip meets the fracture criterion, the mass particle at the crack tip is separated into two particles. The crack then extends in the plate until the plate splits into two parts. The proposed VFIFE-J-integral method was validated by elastic crack simulation of a notched plate, and the VFIFE-FCM method by cohesive crack propagation of a three point bending beam. As assembly of the global stiffness matrix is avoided and each mass particle motion is calculated independently, the proposed method is easy and efficient. Numerical comparisons demonstrate that the present results predicted by the VFIFE method are in agreement with previous analytical, numerical and experimental works.

scholarly journals openVFIFE: An Object-Oriented Structure Analysis Platform Based on Vector Form Intrinsic Finite Element Method

Buildings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 505
Author(s):  
Biao Tan ◽  
Shuyang Cao ◽  
Genshen Fang ◽  
Jinxin Cao ◽  
Yaojun Ge
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Nonlinear Dynamic ◽  
Object Oriented ◽  
Transmission Tower ◽  
Vector Form ◽  
Numerical Examples ◽  
Beam Elements ◽  
Earthquake Load ◽  
Element Method

The vector form intrinsic finite (VFIFE) method is a new and promising structural analysis technique that has many advantages as compared with the conventional finite element method (FEM) in analyzing the complex behaviors of a structure. However, despite the popularization of its application in civil and infrastructure engineering, there is no available unified general analysis framework for it, which limits the applications and developments of VFIFE. This work develops and implements a platform (termed openVFIFE) based on a new proposed object-oriented framework to facilitate the development and application of the vector form intrinsic finite method as well as the efficient and accurate analyses of complex behaviors for civil structures. To validate the platform, a series of numerical examples are conducted. Furthermore, to extend the applications of VFIFE, the nonlinear dynamic and collapse processes of a transmission tower under earthquake load are studied using openVFIFE. The results of these numerical examples simulated by the developed truss or beam elements are consistent with theoretical solutions, previous research or conventional finite element models. The failure modes of the transmission tower under earthquake load simulated by the platform is consistent with those observed in real cases. In addition, the results of nonlinear dynamic analyses of the transmission tower show that the computational efficiency of the proposed platform is 6-10 times higher than that of the conventional finite element method. The results provide sufficient evidence to prove the accuracy and efficiency of the proposed platform in the static, dynamic and elastoplastic analyses of truss and frame structures, especially in the structure analysis characterized by strong geometry nonlinearity. It is noteworthy that in addition to the link and beam elements, further work is undergoing on implementing more elements, such as shell and solid elements. The openVFIFE also allows researchers who are interested in this topic to put their creative ideas into this platform and continuously improve the completeness and applicability of the VFIFE method.

A modified damping model of vector form intrinsic finite element method for high-speed spiral bevel gear dynamic characteristics analysis

2021 ◽  
pp. 030932472110188
Author(s):  
Xiangying Hou ◽  
Yuzhe Zhang ◽  
Hong Zhang ◽  
Jian Zhang ◽  
Zhengminqing Li ◽  
...  
Keyword(s):  
Finite Element ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Numerical Solutions ◽  
Bevel Gear ◽  
Spiral Bevel Gear ◽  
Vector Form ◽  
Good Efficiency ◽  
Spiral Bevel ◽  
Damping Model

The vector form intrinsic finite element (VFIFE) method is springing up as a new numerical method in strong non-linear structural analysis for its good convergence, but has been constricted in static or transient analysis. To overwhelm its disadvantages, a new damping model was proposed: the value of damping force is proportional to relative velocity instead of absolute velocity, which could avoid inaccuracy in high-speed dynamic analysis. The accuracy and efficiency of the proposed method proved under low speed; dynamic characteristics and vibration rules have been verified under high speed. Simulation results showed that the modified VFIFE method could obtain numerical solutions with good efficiency and accuracy. Based on this modified method, high-speed vibration rules of spiral bevel gear pair under different loads have been concluded. The proposed method also provides a new way to solve high-speed rotor system dynamic problems.

Dynamic Characteristic Analysis of Irregularity under Turnout by Vehicle-Turnout Rigid-Flexible Coupling Model

2014 ◽  
Vol 945-949 ◽  
pp. 591-595 ◽  
Author(s):  
Meng Chen ◽  
Yan Yun Luo ◽  
Bin Zhang
Keyword(s):  
Finite Element ◽  
Longitudinal Direction ◽  
Element Model ◽  
Vertical Displacement ◽  
Coupling Model ◽  
Interaction Force ◽  
Vertical Acceleration ◽  
Characteristic Analysis ◽  
Flexible Coupling ◽  
Multi Body

Finite element model of track in frog zone is built by vehicle-turnout system dynamics. Considering variation of rail section and elastic support, bending deformation of turnout sleeper, spacer block and sharing pad effects, the track integral rigidity distribution in longitudinal direction is calculated in the model. Vehicle-turnout rigid-flexible coupling model is built by finite element method (FEM), multi-body system (MBS) dynamics and Hertz contact theory. With the regularity solution that different stiffness is applied for rubber pad under sharing pad of different turnout sleeper zone, analysis the variation of vertical acceleration of bogie and wheelset, rail vertical displacement and wheel-rail interaction force, this paper proves that setting reasonable rubber pad stiffness is an efficient method to solve rigidity irregularity problem.

A Simplified Finite Element for Added Mass and Inertial Coupling in Arrays of Cylinders

1985 ◽  
Vol 107 (2) ◽  
pp. 118-125 ◽  
Author(s):  
R. E. Harris ◽  
M. A. Dokainish ◽  
D. S. Weaver
Keyword(s):  
Finite Element ◽  
Time Integration ◽  
Element Model ◽  
Added Mass ◽  
Cylindrical Structures ◽  
Beam Elements ◽  
Inertial Coupling ◽  
Fundamental Frequencies ◽  
Tube Bundles ◽  
Primary Advantage

A simplified finite element has been developed for modeling the added mass and inertial coupling arising when clusters of cylinders vibrate in a quiescent fluid. The element, which is based on two-dimensional potential flow theory, directly couples two adjacent beam elements representing portions of the adjacent cylindrical structures. The primary advantage of this approach over existing methods is that it does not require the discretization of the surrounding fluid and, therefore, is computationally much more efficient. The fundamental frequencies of tube bundles of various pitch ratios have been predicted using this method and compared with experimental data. Generally, the agreement is good, especially for the bandwidth of fluid coupled natural frequencies. The transient response of tube bundles is also examined using time integration of the finite element model. The beating phenomenon and time decay characteristics exhibited by the experimental bundles under single-tube excitation are well predicted and valuable insights are gained into the measurement of damping in tube bundles.

scholarly journals A Kollár and Pluzsik anisotropic composite beam theory for arbitrary multicelled cross sections

2016 ◽  
Vol 35 (23) ◽  
pp. 1696-1711 ◽  
Author(s):  
Danilo S Victorazzo ◽  
Andre De Jesus
Keyword(s):  
Finite Element ◽  
Cross Sections ◽  
Composite Beam ◽  
Linear Equations ◽  
Beam Theory ◽  
Element Formulation ◽  
Compliance Matrix ◽  
Asymmetric System ◽  
Anisotropic Composite ◽  
Stiffness Matrices

In this paper we extend Kollár and Pluzsik’s thin-walled anisotropic composite beam theory to include multiple cells with open branches and booms, and present a finite element formulation utilizing the stiffness matrix obtained from this theory. To recover the 4 × 4 compliance matrix of a beam containing N closed cells, we solve an asymmetric system of 2N + 4 linear equations four times with unitary section loads and extract influence coefficients from the calculated strains. Finally, we compare 4 × 4 stiffness matrices of a multicelled beam using this method against matrices obtained using the finite element method to demonstrate accuracy. Similarly to its originating theory, the effects of shear deformation and restrained warping are assumed negligible.

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