Component Mode Synthesis of a Vehicle System Model Using the Fictitious Mass Method

2006 ◽  
Vol 129 (1) ◽  
pp. 73-83 ◽  
Author(s):  
M. Karpel ◽  
B. Moulin ◽  
V. Feldgun
Keyword(s):  
Finite Element ◽  
Degrees Of Freedom ◽  
Structural Model ◽  
Synthesis Method ◽  
Normal Modes ◽  
Low Frequency ◽  
Component Mode Synthesis ◽  
Response Analysis ◽  
Element Analysis ◽  
Local Boundary

A new procedure for dynamic analysis of complex structures, based on the fictitious-mass component mode synthesis method, is presented. Normal modes of separate components are calculated by finite-element analysis with the interface coordinates loaded with fictitious masses that generate local boundary deformations in the low-frequency modes. The original fictitious-mass method is extended to include three types of component interconnections: displacement constraints, connection elements, and structural links. The connection elements allow the introduction of springs and dampers between the interface points without adding structural degrees of freedom. The structural links facilitate the inclusion the discrete finite-element representation of typically small components in the coupling equations. This allows a convenient treatment of loose elements and the introduction of nonlinear effects and parametric studies in subsequent analyses. The new procedure is demonstrated with the structural model of a typical vehicle with four major substructures and a relatively large number of interface coordinates. High accuracy is obtained in calculating the natural frequencies and modes of the assembled structure and the separate components with the fictitious masses removed. Dynamic response analysis of the vehicle travelling over a rough road, performed by modal coupling, is in excellent agreement with that performed for the full model.

scholarly journals Spatial Finite Element Analysis for Dynamic Response of Curved Thin-Walled Box Girder Bridges

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Yinhui Wang ◽  
Yidong Xu ◽  
Zheng Luo ◽  
Haijun Wu ◽  
Liangliang Yan
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Degrees Of Freedom ◽  
Response Analysis ◽  
Box Girder Bridges ◽  
Element Analysis ◽  
Box Girder ◽  
Girder Bridges ◽  
System A ◽  
Thin Walled

According to the flexural and torsional characteristics of curved thin-walled box girder with the effect of initial curvature, 7 basic displacements of curved box girder are determined. And then the strain-displacement calculation correlations were established. Under the curvilinear coordinate system, a three-noded curved girder finite element which has 7 degrees of freedom per node for the vibration characteristic and dynamic response analysis of curved box girder is constructed. The shape functions are used as the interpolation functions of variable curvature and variable height to accommodate to the variation of curvature and section height. A MATLAB numerical analysis program has been implemented.

Simplified Seismic Response Analysis Method Using Reduced Model of Piping System

2018 ◽  
Author(s):  
Michiya Sakai ◽  
Ryuya Shimazu ◽  
Shinichi Matsuura ◽  
Ichiro Tamura
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Seismic Response ◽  
Degrees Of Freedom ◽  
Response Analysis ◽  
Piping System ◽  
Element Analysis ◽  
Mass System ◽  
Piping Systems ◽  
Low Degrees

In the seismic response analysis of piping systems, finite element analysis is performed with analysis method guidelines [1]–[4] established based on benchmark analysis. However, since it takes a great deal of effort to carry out finite element analysis, a simplified method to analyze the seismic response of complex piping systems is required. In this research, we propose a method to reduce an equivalent spring-mass system model with low degrees of freedom, which can take into account the main mode of the complicated piping system. Simplified seismic evaluation is carried out using this spring mass system model with low degrees of freedom, and the accuracy of response evaluation is confirmed by comparison with finite element analysis.

A Coupled Finite Element–Wave Based Approach for the Steady-State Dynamic Analysis of Acoustic Systems

2003 ◽  
Vol 11 (02) ◽  
pp. 285-303 ◽  
Author(s):  
B. van Hal ◽  
W. Desmet ◽  
D. Vandepitte ◽  
P. Sas
Keyword(s):  
Finite Element ◽  
Steady State ◽  
Degrees Of Freedom ◽  
Complex Geometry ◽  
Low Frequency ◽  
Response Analysis ◽  
Frequency Range ◽  
Application Range ◽  
State Dynamic ◽  
High Convergence Rate

The finite element method (FEM) is widely accepted for the steady-state dynamic response analysis of acoustic systems. It exhibits almost no restrictions with respect to the geometrical features of these systems. However, it is limited to the low-frequency range due to the rapidly growing model size for increasing frequencies. An alternative method is the wave based method (WBM), which is based on the indirect Trefftz approach. It exhibits better convergence properties than the FEM and therefore allows accurate predictions at higher frequencies. However, the applicability is limited, since the high computational efficiency only appears for systems of moderate geometrical complexity. In order to benefit from the advantageous features of both methods, i.e. the wide application range of the FEM and the high convergence rate of the WBM, the coupling between both methods is proposed. Only the parts of the problem domain with a complex geometry are modeled using the FEM, while the remaining parts are described with a wave based model. The resulting hybrid model contains less degrees of freedom, which allows a further model refinement. The proposed coupled approach has the potential to cover the mid-frequency range, where it is still difficult to obtain satisfactory prediction results with currently existing deterministic techniques.

Modeling and Simulation of Bow-Shaped Piezoelectric Energy Harvester

2014 ◽  
Vol 1033-1034 ◽  
pp. 1338-1342 ◽  
Author(s):  
Bing Jiang ◽  
Shuai Yuan ◽  
Jian Bo Xin ◽  
Li Juan Chen ◽  
Yu Guo Hao ◽  
...  
Keyword(s):  
Finite Element ◽  
Energy Harvester ◽  
Geometric Model ◽  
Broad Band ◽  
Low Frequency ◽  
Research Field ◽  
Response Analysis ◽  
Side Peak ◽  
Element Analysis ◽  
Piezoelectric Energy

In recent years, new energy supply (energy self-sufficiency) technology which can replace the traditional battery supply has become a hot topic in global research field of microelectronic devices. A new low-frequency trapezoidal bow-shaped piezoelectric energy harvester (TBPEH) was proposed. The geometric model and finite element model (FEM) were built. The static analysis, modal analysis and harmonic response analysis of the TBPEH were discussed by using the Finite Element Analysis(FEA). Then traditional rectangular bow-shaped piezoelectric energy harvester(RBPEH) was compared with the new TBPEH. Simulation showed that the TBPEH could harvest energy more effectively than the RBPEH. The output voltage was increased by 135% with little change in resonant frequency, and indicator of the inhibition of side peak (SPI) which represented the capability of broad-band energy harvesting rose 11.2%. The TBPEH resonance frequency is 34.1Hz, which can be applied to the low frequency environment.

Use of the Finite Element Analysis Method in Pedodontics

2018 ◽  
Vol 55 (4) ◽  
pp. 666-675
Author(s):  
Mihaela Tanase ◽  
Dan Florin Nitoi ◽  
Marina Melescanu Imre ◽  
Dorin Ionescu ◽  
Laura Raducu ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Structural Model ◽  
Analysis Method ◽  
Ansys Software ◽  
Concentrated Force ◽  
Element Analysis ◽  
Finite Element Analysis Method ◽  
The Finite Element Analysis ◽  
Solid Type

The purpose of this study was to determinate , using the Finite Element Analysis Method, the mechanical stress in a solid body , temporary molar restored with the self-curing GC material. The originality of our study consisted in using an accurate structural model and applying a concentrated force and a uniformly distributed pressure. Molar structure was meshed in a Solid Type 45 and the output data were obtained using the ANSYS software. The practical predictions can be made about the behavior of different restorations materials.

The Finite Element Analysis and Optimization for the Grinder Based on the Joint Surface

2013 ◽  
Vol 281 ◽  
pp. 165-169 ◽  
Author(s):  
Xiang Lei Zhang ◽  
Bin Yao ◽  
Wen Chang Zhao ◽  
Ou Yang Kun ◽  
Bo Shi Yao
Keyword(s):  
Finite Element ◽  
Natural Frequency ◽  
Element Model ◽  
Joint Surface ◽  
Weak Links ◽  
Response Analysis ◽  
Element Analysis ◽  
Static And Dynamic Analysis ◽  
Harmonic Response Analysis ◽  
Grinding Machine

Establish the finite element model for high precision grinding machine which takes joint surface into consideration and then carrys out the static and dynamic analysis of the grinder. After the static analysis, modal analysis and harmonic response analysis, the displacement deformation, stress, natural frequency and vibration mode could be found, which also helps find the weak links out. The improvement scheme which aims to increase the stiffness and precision of the whole machine has proposed to efficiently optimize the grinder. And the first natural frequency of the optimized grinder has increased by 68.19%.

Fitness for Service Assessments of Bulging and Out-of-Round Structures

2004 ◽  
Author(s):  
Peter Carter ◽  
D. L. Marriott ◽  
M. J. Swindeman
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Internal Pressure ◽  
Structural Model ◽  
External Pressure ◽  
Element Analysis ◽  
Structural Imperfection ◽  
Level 2

This paper examines techniques for the evaluation of two kinds of structural imperfection, namely bulging subject to internal pressure, and out-of-round imperfections subject to external pressure, with and without creep. Comparisons between comprehensive finite element analysis and API 579 Level 2 techniques are made. It is recommended that structural, as opposed to material, failures such as these should be assessed with a structural model that explicitly represents the defect.

Selection of Degrees of Freedom for Dynamic Analysis

1987 ◽  
Vol 109 (1) ◽  
pp. 65-69 ◽  
Author(s):  
K. W. Matta
Keyword(s):  
Finite Element ◽  
Dynamic Analysis ◽  
Degrees Of Freedom ◽  
General Purpose ◽  
Component Mode Synthesis ◽  
Complex Structures ◽  
Large Complex ◽  
Static Condensation ◽  
Basis Vectors ◽  
Selection Of

A technique for the selection of dynamic degrees of freedom (DDOF) of large, complex structures for dynamic analysis is described and the formulation of Ritz basis vectors for static condensation and component mode synthesis is presented. Generally, the selection of DDOF is left to the judgment of engineers. For large, complex structures, however, a danger of poor or improper selection of DDOF exists. An improper selection may result in singularity of the eigenvalue problem, or in missing some of the lower frequencies. This technique can be used to select the DDOF to reduce the size of large eigenproblems and to select the DDOF to eliminate the singularities of the assembled eigenproblem of component mode synthesis. The execution of this technique is discussed in this paper. Examples are given for using this technique in conjunction with a general purpose finite element computer program GENSAM[1].

Identification of a Significantly Non-Proportionally Damped Structure Using Force Appropriation

1995 ◽  
Author(s):  
P. S. Holmes ◽  
J. R. Wright ◽  
J. E. Cooper
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Normal Mode ◽  
Normal Modes ◽  
Dynamic Tests ◽  
High Quality ◽  
Element Analysis ◽  
Standard Curve ◽  
Complex Modes ◽  
Phase Resonance

Abstract Dynamic tests were carried out on an aluminium plate with significant non-proportional damping applied via two oil filled dampers. Normal mode force appropriation (phase resonance) methods were used to measure the undamped normal modes of the plate and the results compared with corresponding complex modes obtained using a standard curve fitting (phase separation) approach. It is demonstrated that, as long as suitable excitation positions are chosen, high quality undamped normal modes can be identified while the curve fitted modes are highly complex. A Finite Element analysis of the plate was used to show how the results of normal mode force appropriation are directly comparable, particularly when damping is non-proportional.

The Finite Element Analysis of Dynamic Interaction of High-Speed Shinkansen, the Rail, and Bridge

1993 ◽  
Author(s):  
Makoto Tanabe ◽  
Hajime Wakui ◽  
Nobuyuki Matsumoto
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
High Speed ◽  
Response Analysis ◽  
Element Formulation ◽  
Element Analysis ◽  
Finite Element Program ◽  
The Finite Element Analysis ◽  
Element Program ◽  
The Impact

Abstract A finite element formulation to solve the dynamic behavior of high-speed Shinkansen cars, rail, and bridge is given. A mechanical model to express the interaction between wheel and rail is described, in which the impact of the rail on the flange of wheel is also considered. The bridge is modeled by using various finite elements such as shell, beam, solid, spring, and mass. The equations of motions of bridge and Shinkansen cars are solved under the constitutive and constraint equations to express the interaction between rail and wheel. Numerical method based on a modal transformation to get the dynamic response effectively is discussed. A finite element program for the dynamic response analysis of Shinkansen cars, rail, and bridge at the high-speed running has been developed. Numerical examples are also demonstrated.

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