The Simplified Analytical Method for Computing Dynamic Characteristics of Transmission Steel Towers

2011 ◽  
Vol 105-107 ◽  
pp. 303-306
Author(s):  
Jing Bo Yang ◽  
Jin Fei Zhao ◽  
Jun Jiang
Keyword(s):  
Dynamic Characteristics ◽  
Analytical Methods ◽  
Natural Vibration ◽  
Head Width ◽  
Natural Vibration Frequency ◽  
The Finite Element Method ◽  
Root Space ◽  
Lumped Mass ◽  
Mode Of Transmission ◽  
Tower Height

Based on vibration theory, simplified analytical methods for computing the first natural vibration frequency and mode of transmission steel tower are investigated, which has improved the currently applied method. The method for frequency includes parameters of lumped mass such as tower head or cross arm, and can show the influence of section of tower main leg. The method for mode considers tower height, root space and head width. Examples of some typical transmission steel towers show that the dynamic characteristics computed with the simplified analytical methods are close to those of the Finite Element Method. Then the methods given in this paper are superior to the present methods used in engineering and have a better generality, which are suitable to different tower type structures.

scholarly journals Analysis of the natural oscillation frequency of the long-span trusses with flanged connections

2021 ◽  
pp. 76-85
Author(s):  
Татьяна Георгиевна Рытова ◽  
Людмила Анатольевна Максимова ◽  
Анастасия Георгиевна Николаева ◽  
Татьяна Михайловна Макарова ◽  
Надежда Георгиевна Пфаненштиль
Keyword(s):  
Dynamic Characteristics ◽  
Vibration Frequency ◽  
Natural Vibration ◽  
Natural Oscillation ◽  
Natural Vibration Frequency ◽  
Building Structures ◽  
Long Span ◽  
Local Areas ◽  
Calculation Results ◽  
Natural Oscillation Frequency

Приводится анализ частоты собственных колебаний большепролетной фермы с фланцевыми соединениями. Выполнен расчет фланцевого соединения с различными случаями исключения болтов из работы соединения. Анализ результата расчета показал, что возникновение повреждений и дефектов конструкций здания в локальных зонах, величина которых несущественно снижает общую жесткость каркаса, практически не влияет на динамические характеристики каркаса. The analysis of the natural vibration frequency of a large-span truss with flanged connections is given. The calculation of the flange connection with various cases of exclusion of bolts from the connection operation is performed. Analysis of the calculation results showed that the occurrence of damage and defects in the building structures in local areas, the value of which significantly reduces the overall rigidity of the frame, practically does not affect the dynamic characteristics of the frame.

Elastic Wave Propagation in Hierarchical Honeycombs With Woodpile-Like Vertexes

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Zhiwei Zhu ◽  
Zichen Deng ◽  
Jianke Du
Keyword(s):  
Wave Propagation ◽  
Elastic Wave ◽  
Natural Vibration ◽  
Elastic Wave Propagation ◽  
Natural Vibration Frequency ◽  
The Finite Element Method ◽  
Wave Velocities ◽  
Static Phase ◽  
Bloch’S Theorem ◽  
Identical Band

This paper investigates the dispersion behavior of elastic wave propagation in hierarchical honeycombs using the finite element method in conjunction with the Bloch's theorem. The hierarchical honeycomb is constructed by replacing each vertex of a regular hexagonal honeycomb with smaller hexagons stacked in a woodpile pattern. Band structure analysis reveals that, in the considered range of frequency, the maximum band gap for the hierarchical honeycomb is localized in the frequency corresponding to the natural vibration frequency of the cell strut, and moreover, the width of this particular gap is significantly broadened as the order of hierarchy increases. In addition, for the hierarchical honeycombs satisfying an invariable ratio between the thickness and squared length of the cell strut, which is extracted from the expression of the natural frequency of the simply supported element beam, a coincidence among dispersion curves (or contours) for the hierarchical configurations with the same scale order occurs. The resulting identical band gaps as well as the quasi-static phase wave velocities provide an advantage or the hierarchical honeycombs in the manipulation of vibration and associated multifunction designs.

scholarly journals Dynamic Characteristics Analysis and Experimental Verification of Long Span Suspension Bridge

2021 ◽  
Vol 272 ◽  
pp. 01019
Author(s):  
Guojun Yang ◽  
Qiwei Tian ◽  
Guangwu Tang ◽  
Longlong Li ◽  
Su Ye ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Vibration Frequency ◽  
Natural Vibration ◽  
Structural Parameters ◽  
Great Influence ◽  
Suspension Bridge ◽  
Natural Vibration Frequency ◽  
Vibration Modes ◽  
Dead Load ◽  
Long Span

The dynamic characteristics of long-span suspension bridges are complex. The natural vibration frequency is changed with different structural parameters, and the sensitivity to different parameters is different. In order to solve this problem, the spatial model of a long-span suspension bridge was established by using finite element software, and the first 20 natural vibration periods, natural vibration frequencies and vibration modes were analyzed and calculated. The accuracy of the obtained natural vibration frequency data was verified through field tests. Finally, based on the model, the stiffness of structural components is studied by one -factor-at-one-time, and the influence of various variables on the frequency and mode of a certain mode is studied by one-factor-at-one-time method. The results show that different structural parameters have different effects on the vibration frequency. When the stiffness of stiffening girder and main tower is changed, with the increase of stiffness, the variation of frequency mostly presents an upward trend, and the range is large. With the change of the secondary dead load, most of the frequencies decrease first and then tend to be stable. It can be seen from the field test results that the vibration shapes and frequencies measured by numerical simulation and test are close to each other, which can meet the requirements of engineering precision. The stiffness of the main cable and the main tower has a great influence on the modes and periods corresponding to them. The increase of the secondary dead load can reduce the natural vibration frequency of the suspension bridge, but it is not unlimited to increase the secondary dead load to reduce the frequency. The stiffness of the stiffening girder has a great influence on the frequency of the suspension bridge. When the bending stiffness of the stiffening girder increases to 3 times of the original one, the order of vibration modes of the structure will change. The research results can provide references for structural design and dynamic parameter adjustment of long-span suspension bridge.

scholarly journals SENSITIVITY OF STRENGTH, RIGID AND DYNAMIC CHARACTERISTICS OF THE CONSOLE ROTOR TO VARIATION OF DESIGN PARAMETERS

2021 ◽  
pp. 104-113
Author(s):  
Mykola А. Tkachuk ◽  
Andrey Grabovskiy ◽  
Nickolay Prokopenko ◽  
Mykola M. Tkachuk ◽  
Oleksandr Shut ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Modulus Of Elasticity ◽  
Natural Vibration ◽  
Rotation Speed ◽  
Design Parameters ◽  
Natural Vibration Frequency ◽  
Radial And Axial Displacements ◽  
Angular Velocities ◽  
Air Blower ◽  
Critical Rotation Speed

The analysis sensitivity of strength, rigid and dynamic characteristics of the console rotor to variation of design parameters in paper describes The speed of rotation of the shaft, the material of the impeller vary. The dependences of radial and axial displacements on the angular velocities of rotation and the modulus of elasticity of the impeller material are established. For objects of the type of rotary systems with a cantilever arrangement of the impeller, not one, but a set of criteria has been introduced into consideration, which should be taken into account in the research of this type of objects. The tendencies of change of the first and second critical rotational speeds from the modulus of elasticity, rotor rotational frequencies and density of the impeller material are also determined. On this basis, recommendations have been developed for determining the design parameters of the rotor part of the air blower with a cantilevered impeller. Keywords: air blower; critical rotation speed; natural vibration frequency; rotary system; stress-strain state

Study on Fluid-Solid Coupling Analysis Method of Bridge Pier

2012 ◽  
Vol 594-597 ◽  
pp. 1504-1508
Author(s):  
Ji Xin Yang ◽  
Sheng Rong Zuo ◽  
Yi Feng Huang
Keyword(s):  
Numerical Analysis ◽  
Water Level ◽  
Dynamic Characteristics ◽  
Vibration Frequency ◽  
Natural Vibration ◽  
Frequency Effect ◽  
Natural Vibration Frequency ◽  
Strong Impact ◽  
Analysis Method ◽  
Coupling Analysis

This paper introduces the numerical analysis method to analyze the dynamic characteristics of pier in water. The method comes to realize by the software ANSYS. By the calculating of ANSYS, the 1~3 order frequency can be found regular when the pier in full of water and anhydrous conditions. Water has a strong impact on natural vibration frequency of structures, as the water level rises, the natural vibration frequency decreases gradually, the value of the reducing is about 13%. At the same time, the frequency decreases as an increasing rate. So the natural frequency effect which the water acting on the structure can not be ignored.

The Application of BESO in Vibration Damping of Ship Plate

2013 ◽  
Vol 572 ◽  
pp. 185-188 ◽  
Author(s):  
Xiao Yan Teng ◽  
Jia Shan Han ◽  
Liang Peng
Keyword(s):  
Natural Vibration ◽  
Target Function ◽  
Vibration Damping ◽  
Natural Vibration Frequency ◽  
Constraint Condition ◽  
Evolutionary Structural Optimization ◽  
Damping Material ◽  
Reasonable Result ◽  
Beso Method ◽  
Original Amount

Based on the bi-directional evolutionary structural optimization (BESO), the method of determining the adhesion position of the damping material is proposed in this paper, which is applicable to the vibration damping of ship plate. In this method, the needed amount of damping material is taken as the constraint condition, and the maximization of one natural vibration frequency of the structure is taken as the target function. A thin plate structure with both ends constraints has been taken as an example to get the best topology structure of its adhesion damper by taking the BESO method. The result of optimization shows that it still meets the damping requirements when the needed amount of damping material decreases by about 50% of the original amount. The reasonable result demonstrates the effectiveness and engineering value of the method.

Study on the Influence of Reactor Core Structure on Reactor Natural Vibration Frequency

2021 ◽  
Author(s):  
Yuan Zhou ◽  
Tian Tian ◽  
Xiongfei Yu ◽  
Ran Ren ◽  
Liangcai Zhou ◽  
...  
Keyword(s):  
Vibration Frequency ◽  
Natural Vibration ◽  
Reactor Core ◽  
Core Structure ◽  
Natural Vibration Frequency

scholarly journals Dynamic Modeling and Experiment Research on Twin Ball Screw Feed System Considering the Joint Stiffness

Symmetry ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 686 ◽  
Author(s):  
Meng Duan ◽  
Hong Lu ◽  
Xinbao Zhang ◽  
Yongquan Zhang ◽  
Zhangjie Li ◽  
...  
Keyword(s):  
Dynamic Modeling ◽  
Dynamic Characteristics ◽  
Friction Model ◽  
Numerical Control ◽  
Ball Screw ◽  
Cnc Machine Tools ◽  
Axial Stiffness ◽  
Cnc Machine ◽  
Feed System ◽  
Lumped Mass

It is of great significance to study the dynamic characteristics of twin ball screw (TBS) feed system to improve the precision of gantry-type dual-driven computer numerical control (CNC) machine tools. In this paper, an equivalent dynamic model of the TBS feed system is established utilizing lumped mass method considering the stiffness of joints. Equivalent axial stiffness of screw-nut joints and bearing joints are both calculated by Hertz contact theory. Furthermore, a friction model is proposed because the friction force of the screw nut affects the stiffness of the joints. Then, the friction parameters are obtained by using the nonlinear system identification method. Meanwhile, a finite element model (FEM) is developed to assess the dynamic characteristics of TBS feed system under the stiffness of joints. Finally, validation experiments are conducted, and the results show that the positions of the nut and the velocities of worktable greatly affect the dynamic characteristics of the TBS feed system. Compared with the theoretical calculation, FEM and experiments indicate that the dynamic modeling proposed in this article can reach a higher accuracy.

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