Influence of Supports and Water Depths on Dynamic Characteristics of Aqueduct Structure

2011 ◽  
Vol 243-249 ◽  
pp. 4592-4595
Author(s):  
Xin Li Bai ◽  
Hai Li Su ◽  
Qian Pan
Keyword(s):  
Water Depth ◽  
Dynamic Characteristics ◽  
Mode Shape ◽  
Mode Shapes ◽  
Element Analysis ◽  
Characteristics Analysis ◽  
Simple Support ◽  
North Water ◽  
Completely Simple ◽  
Water Depths

In this paper, dynamic characteristics analysis is carried out for a large aqueduct of South-to-North Water Transfer Project using large finite element analysis software. Two kinds of connection supports are considered, namely elastic support and completely simple support. Six kinds of water depths are calculated by additional mass method: empty aqueduct, 1/4 water depth, 1/2 water depth, 3/4 water depth, designed water depth, full water depth. Results show that basin type rubber support strengthens the constraint to aqueduct, and strengthens the connection of aqueduct to pier, and also increases the system stiffness, therefore the natural frequency is higher than that of completely simple support; The influence of water to dynamic characteristics of the aqueduct is quite obvious, so water effect must be considered in computation; Water has no influence on the principal mode shapes of the aqueduct structure, i.e. the dry mode shape and the wet mode shape are similar in appearance.

Dynamic Characteristics Analysis of a Large Aqueduct

2011 ◽  
Vol 255-260 ◽  
pp. 1130-1133
Author(s):  
Bing Bai ◽  
Yu He Li ◽  
Xiao Shan Deng
Keyword(s):  
Seismic Design ◽  
Water Depth ◽  
Dynamic Characteristics ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Element Analysis ◽  
Characteristics Analysis ◽  
Practical Engineering ◽  
North Water ◽  
Dynamic Characteristics Analysis

By use of large finite element analysis software, dynamic characteristics analysis is carried out for an aqueduct in South-to-North Water Transfer Project. Westergaard method and Housner method are used respectively to simulate the water. The natural frequencies and mode shapes (wet) of the aqueduct structure are calculated under two kinds of water depths (designed water depth, half water depth). The results show that the influence of the water on the dynamic characteristics of the aqueduct is obvious. Natural frequencies decrease with the increases of the water depth. The distinction between the two methods was analyzed: Housner method is closer to the practical engineering because both the pulsation effect and the convection effect of the water are considered. The results and conclusions can be referenced for seismic design of large aqueduct.

Design for Desired Mode Shapes: Preliminary Results

1998 ◽  
Author(s):  
Elizabeth K. Lai ◽  
G. K. Ananthasuresh
Keyword(s):  
Finite Element ◽  
Feasibility Study ◽  
Mode Shape ◽  
Longitudinal Axis ◽  
Mode Shapes ◽  
Future Research ◽  
Structural Members ◽  
Element Analysis ◽  
Cross Sectional ◽  
Made In

Abstract This paper is concerned with the shape optimization of structures to attain prescribed normal mode shapes. Optimizing structural members in order to have desired mode shapes, besides the desired natural frequencies, is of interest in some applications at both macro and micro scales. After reviewing the relevant past work on the “inverse mode shape” problem, a feasibility study using the lumped spring-mass models and finite element models of an axially vibrating bar is presented. Based on the observations made in the feasibility study with bars, a meaningful optimization problem is formulated and solved. Using finite element analysis and numerical optimization, a method for designing beam-like structures for prescribed mode shapes is developed. The method is demonstrated with an example of designing the cross-sectional area profile of a beam along its longitudinal axis to get a desired fundamental mode shape. The nonuniqueness of the solution is noted and avenues for future research are identified.

Static and Dynamic Characteristics Analysis of HTM125 Milling Complex Machining Center Column

2014 ◽  
Vol 1077 ◽  
pp. 191-196
Author(s):  
Yu Hou Wu ◽  
Yu Hang Ren ◽  
De Hong Zhao ◽  
Feng Lu
Keyword(s):  
Dynamic Characteristics ◽  
Three Dimensional ◽  
Mode Shapes ◽  
Three Dimensional Model ◽  
Static And Dynamic Characteristics ◽  
Machining Center ◽  
Characteristics Analysis ◽  
Object Of Study ◽  
Five Axis ◽  
Dynamic Characteristics Analysis

The column of heavy double turret five-axis horizontal milling complex machining center is taken as the object of study. Solidworks is used to establish three-dimensional model of milling machining center column, the established modal is be imported into ANSYS Workbench for static and dynamic characteristics analysis. First, by comparing the column deformation, the stress and strain under no-load and load conditions, which is concluded that column design is too conservative and be optimized. Secondly, the modal analysis was carried out on the column, which provides a theoretical basis for the optimization of the column by getting the first six natural frequencies and mode shapes of cloud.

Vibration Characteristics Analysis of an Aero-Engine Turbine Blade

2012 ◽  
Vol 487 ◽  
pp. 894-897
Author(s):  
Wei Qiang Zhao ◽  
Yong Xian Liu ◽  
Mo Wu Lu ◽  
Qing Jun Guo
Keyword(s):  
Optimal Design ◽  
Turbine Blade ◽  
Dynamic Characteristics ◽  
Natural Frequencies ◽  
Vibration Characteristics ◽  
Mode Shapes ◽  
Vibration Characteristic ◽  
Analysis Method ◽  
Aero Engine ◽  
Characteristics Analysis

This paper introduces the FEA method for a certain type of aero-engine turbine blade and makes a vibration characteristics analysis to this aero-engine turbine blade based on this method. The vibration characteristic of this aero-engine turbine blade is studied and the natural modal of the turbine blade is calculated based on UG software. The first six natural frequencies and mode shapes are given. According to the analysis results the dynamic characteristics of the blade are discussed. The analysis method and results in this paper can be used for further study on optimal design and vibration safety verification for the blade.

Dynamic Characteristic Analysis of CNC Turret Punch Servo Beam

2016 ◽  
Vol 836-837 ◽  
pp. 522-528
Author(s):  
Yan Jun Guo
Keyword(s):  
Dynamic Characteristics ◽  
Optimization Design ◽  
Natural Frequencies ◽  
Element Model ◽  
Mode Shapes ◽  
Characteristic Analysis ◽  
Boundary Constraints ◽  
Modeling Methodology ◽  
Characteristics Analysis ◽  
Dynamic Characteristics Analysis

This paper resolved CNC turret punch cause vibration phenomenon in the course of processing sheet,analysis of its dynamic characteristics of the beam servo feed mechanism, using the method of constrained modal analysis.Through the establishment of finite element model exactly for the servo beam and setting the boundary elastic restraint stiffness, solving the natural frequencies and mode shapes of the servo beam under boundary constraints and loading conditions. Constraints modal analysis results are consistent with experimental monitoring results of CNC turret punch servo beam. This modeling methodology and results of the analysis has a high practical value for CNC turret punch dynamic characteristics analysis and structural optimization design.

FEA on Vibration Characteristics of a Shrouded Turbine Blade

2012 ◽  
Vol 189 ◽  
pp. 443-447
Author(s):  
Wei Qiang Zhao ◽  
Yong Xian Liu ◽  
Mo Wu Lu
Keyword(s):  
Optimal Design ◽  
Modal Analysis ◽  
Turbine Blade ◽  
Dynamic Characteristics ◽  
Natural Frequencies ◽  
Vibration Characteristics ◽  
Mode Shapes ◽  
Software Environment ◽  
Aero Engine ◽  
Characteristics Analysis

This paper introduces a FEA method for vibration characteristics analysis of an aero-engine shrouded turbine blade and makes an actual modal analysis of this shrouded blade based on this method in UG software environment. The first six natural frequencies and mode shapes of this shrouded blade are calculated. And also, the dynamic characteristics of the shrouded turbine blade are discussed in detail according to the analysis results. The FEA method and the vibration characteristics analysis results in the paper can be used for optimal design and vibration safety verification of this aero-engine shrouded turbine blade.

Finite Element Modal Analysis for Face-Milling Cutter

2013 ◽  
Vol 589-590 ◽  
pp. 19-22
Author(s):  
Lu Ning Liu ◽  
Zhen Yu Shi ◽  
Zhan Qiang Liu
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Face Milling ◽  
Operating Conditions ◽  
Mode Shapes ◽  
Milling Cutter ◽  
Characteristics Analysis ◽  
The Face

In this paper, a face-milling tool system is dealt with the Finite Element Modal Analysis (FEMA) using advanced contact technology functionalities. Dynamic characteristics analysis is performed and the stiffness contribution is included in the modal pre-stressed analysis. Natural frequencies and mode shapes of vibration are calculated. The FEMA is followed by experiments performed for different operating conditions of the face-milling system. The dynamic characteristics obtained in this paper can be used to optimize the face-milling cutter in high speed machining.

scholarly journals Structural Damage Identification Based on Principal Curvatures of Mode Shape

2020 ◽  
Vol 25 (4) ◽  
pp. 566-576
Author(s):  
Rahim Gorgin ◽  
Ziping Wang
Keyword(s):  
Mode Shape ◽  
Structural Damage ◽  
Damage Identification ◽  
Mode Shapes ◽  
Principal Curvatures ◽  
Element Analysis ◽  
Identification Methods ◽  
Maximum Curvature ◽  
Curvature Variation ◽  
Identification And Characterization

This paper presents a procedure for damage identification and characterization on plates, based on the principal curvatures of their first mode shape. Each mode shape represents the displacement of the structure at its corresponding natural frequency. Since, variations in the geometry due to cracks or material property degradation, make changes in the mode shapes of the structure, such changes can be used for damage identification methods. The presented procedure only requires the first mode shape of the intact and damaged structure. It is shown that the principal curvatures of the surface defined by the first mode shape of the structure, are sensitive to damage and the maximum principal curvature can be used to highlight damages on the structure. The performance of the developed method is firstly evaluated using finite element analysis. To this aim, the procedure is applied to highlight both single and multi-damages in different locations of the plate with different boundary conditions. It is shown that the location of the maximum curvature variation coincides well with the location of damages and the amount of the maximum curvature change can be used as a parameter to describe damage severity. The accuracy of the proposed method is also experimentally verified by test on an aluminum plate and it is demonstrated that the proposed method remains effective even in experimental condition when only a limited number of measurements are available.

Dynamic Characteristics of a Submerged, Flexible Cylinder Vibrating in Finite Water Depths

1992 ◽  
Vol 36 (02) ◽  
pp. 154-167
Author(s):  
A. Ergin ◽  
W. G. Price ◽  
R. Randall ◽  
P. Temarel
Keyword(s):  
Free Surface ◽  
Resonance Frequency ◽  
Water Depth ◽  
Dynamic Characteristics ◽  
Mode Shapes ◽  
Flexible Cylinder ◽  
Rigid Boundary ◽  
Fluid Structure ◽  
Resonance Frequencies ◽  
Theoretical Predictions

This paper presents experimental data and theoretical predictions of the dynamic characteristics (natural and resonance frequencies, mode shapes) of a flexible cylinder vibrating in air and at fixed positions below a free surface in water of finite depth. The flat-ended, thin cylindrical shell of overall length 1284 mm, external radius 180 mm, thickness 3 mm is made of mild steel. In the experiments, the shell was tethered (i) at 0.21, 0.23, and 0.68 m depths below the free surface in water of depth 1.6 m and (ii) at 0.25, 1.5, and 3.5 m depths in 4 m of water. The resonance frequency data recorded provide measures of the influences of free surface, cylinder position, rigid boundary, water depth, etc. occurring in the fluid-structure interaction process. The theoretical predictions are derived from a three-dimensional hydroelastic mathematical model which, through the calculations of the generalized fluid loadings, accounts for the influence of free surface and rigid boundaries, position of submerged cylinder, neutral buoyancy or, as in the present case, with tethers and buoyancy effects. An extensive comparison of results is included. The experimental restrictions of water depth, cylinder position, etc. and the fluid-structure interactions are assessed and illustrated through the calculated resonance frequency values.

Dynamic Characteristics Analysis and Topology Optimization of Column Based on Finite Element Method

2013 ◽  
Vol 721 ◽  
pp. 541-544
Author(s):  
Jing Chen ◽  
Ze Long Yang ◽  
Xian Xuan Li
Keyword(s):  
Finite Element ◽  
Topology Optimization ◽  
Frequency Response ◽  
Dynamic Characteristics ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Response Analysis ◽  
Response Curves ◽  
Element Analysis ◽  
Column Structure

Aiming to improve the dynamic and static characteristics of a type of machining center column, the finite element modal analysis and harmonic response analysis of the column are performed, and this paper analyzes the dynamic characteristics of the column based on the first five mode shapes and natural frequencies of the column and the displacement - frequency response curves of the column. Topology optimization analysis of the column is performed with ANSYS, and the finite element analysis is performed on the column again after the column structure is improved based on the optimal distribution of material of the column structure and the design experience of column. The result shows that the first five natural frequencies of the column increase, the peak of the displacement - frequency response of the column decrease, and the dynamic characteristics are improved significantly.

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