scholarly journals Frequency Analysis of Concrete Gravity Dam with Finite Element Model and LHS Method

2019 ◽  
Vol 3 (3) ◽  
pp. 13-19
Author(s):  
M. Pasbani Khiavi ◽  
A. Feizi ◽  
M. Jalali ◽  
◽  
◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Frequency Analysis ◽  
Element Model ◽  
Gravity Dam ◽  
Concrete Gravity Dam

An Efficient Approach for the Frequency Analysis of Nonaxisymmetric Rotating Structures: Application to a Coupled Bladed Birotor System

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Cécile Dumartineix ◽  
Benjamin Chouvion ◽  
Fabrice Thouverez ◽  
Marie-Océane Parent
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Dynamic Behavior ◽  
Frequency Analysis ◽  
Equations Of Motion ◽  
Element Model ◽  
Variable Coefficients ◽  
Time Dependent ◽  
Time Saving ◽  
Mechanical Coupling

The improvement of efficiency in the design of turbomachines requires a reliable prediction of the vibrating behavior of the whole structure. The simulation of blades vibrations is decisive and this is usually based on elaborated finite element model restricted to the bladed-disk. However, the blades dynamic behavior can be strongly affected by interactions with other parts of the engine. Global dynamic studies that consider these other parts are required but usually come with a high numerical cost. In the case of a birotor architecture, two coaxial rotors with different rotating speeds can be coupled with a bearing system. The mechanical coupling between the shafts generates energy exchange that alters the dynamic behavior of the blades. The equations of motion of the whole structure that take into account the coupling contain periodic time-dependent coefficients due to the difference of rotational speed between both rotors. Equations of this kind, with variable coefficients, are typically difficult to solve. This study presents a preprocessing method to guarantee the elimination of time-dependent coefficients in the birotor equations of motion. This method is tested with a simplified finite element model of two bladed-disks coupled with linear stiffnesses. We obtain accurate results when comparing frequency analysis of preprocessed equations with time-integration resolution of the initial set of equations. The developed methodology also offers a substantial time saving.

An Efficient Approach for the Frequency Analysis of Non-Axisymmetric Rotating Structures: Application to a Coupled Bladed Bi-Rotor System

2018 ◽  
Author(s):  
Cécile Dumartineix ◽  
Benjamin Chouvion ◽  
Fabrice Thouverez ◽  
Marie-Océane Parent
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Dynamic Behavior ◽  
Frequency Analysis ◽  
Equations Of Motion ◽  
Element Model ◽  
Variable Coefficients ◽  
Time Dependent ◽  
Time Saving ◽  
Mechanical Coupling

The improvement of efficiency in the design of turbomachines requires a reliable prediction of the vibrating behavior of the whole structure. The simulation of blades vibrations is decisive and this is usually based on elaborated finite element model restricted to the bladed-disk. However the blades dynamic behavior can be strongly affected by interactions with other parts of the engine. Global dynamic studies that consider these other parts are required but usually come with a high numerical cost. In the case of a bi-rotor architecture, two coaxial rotors with different rotating speed can be coupled with a bearing system. The mechanical coupling between the shafts generates energy exchange that alters the dynamic behavior of the blades. The equations of motion of the whole structure that take into account the coupling contain periodic time-dependent coefficients due to the difference of rotational speed between both rotors. Equations of this kind, with variable coefficients, are typically difficult to solve. This study presents a preprocessing method to guarantee the elimination of time-dependent coefficients in the bi-rotor equations of motion. This method is tested with a simplified finite element model of two bladed-disks coupled with linear stiffnesses. We obtain accurate results when comparing frequency analysis of preprocessed equations with time-integration resolution of the initial set of equations. The developed methodology also offers a substantial time saving.

Analysis for 3-D Seepage Field of Gravity Dam Foundation

2012 ◽  
Vol 468-471 ◽  
pp. 335-338
Author(s):  
Rui Rong Xu ◽  
Wen Ting Zhan ◽  
Qing Xu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Gravity Dam ◽  
Seepage Field ◽  
Dam Foundation ◽  
Initial Flow ◽  
Seepage Problem ◽  
Equivalent Method ◽  
The Finite Element Model

An equivalent method that simulate drainage holes is adopted in the analysis of 3-D seepage field. The Initial Flow Method is applied in this paper to deal with the unconfined seepage problem. In this paper, the finite element model of a gravity dam project is established and the seepage field is analyzed.

Finite Element Simulation of Tire-Rim Interface

1989 ◽  
Vol 17 (4) ◽  
pp. 305-325 ◽  
Author(s):  
N. T. Tseng ◽  
R. G. Pelle ◽  
J. P. Chang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Finite Element Simulation ◽  
Contact Pressure ◽  
Element Model ◽  
Experimental Measurements ◽  
Inflation Pressure ◽  
Interference Fit ◽  
Element Simulation ◽  
Rubber Composite

Abstract A finite element model was developed to simulate the tire-rim interface. Elastomers were modeled by nonlinear incompressible elements, whereas plies were simulated by cord-rubber composite elements. Gap elements were used to simulate the opening between tire and rim at zero inflation pressure. This opening closed when the inflation pressure was increased gradually. The predicted distribution of contact pressure at the tire-rim interface agreed very well with the available experimental measurements. Several variations of the tire-rim interference fit were analyzed.

Torsional Analysis of a Steel Cord-Rubber Tire Belt Structure

1996 ◽  
Vol 24 (4) ◽  
pp. 339-348 ◽  
Author(s):  
R. M. V. Pidaparti
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Composite Structures ◽  
Three Dimensional ◽  
Element Model ◽  
Torsional Stiffness ◽  
Element Analysis ◽  
Rubber Belt ◽  
Steel Cord ◽  
Torsional Analysis

Abstract A three-dimensional (3D) beam finite element model was developed to investigate the torsional stiffness of a twisted steel-reinforced cord-rubber belt structure. The present 3D beam element takes into account the coupled extension, bending, and twisting deformations characteristic of the complex behavior of cord-rubber composite structures. The extension-twisting coupling due to the twisted nature of the cords was also considered in the finite element model. The results of torsional stiffness obtained from the finite element analysis for twisted cords and the two-ply steel cord-rubber belt structure are compared to the experimental data and other alternate solutions available in the literature. The effects of cord orientation, anisotropy, and rubber core surrounding the twisted cords on the torsional stiffness properties are presented and discussed.

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