A New Mistuning Form in Periodic Structure - Force Mistuning

2012 ◽  
Vol 562-564 ◽  
pp. 2092-2096 ◽  
Author(s):  
Guo Hui Yang ◽  
Ai Lun Wang ◽  
Xu Hui Cao
Keyword(s):  
Periodic Structure ◽  
Vibration Mode ◽  
Vibration Characteristics ◽  
Vibration Response ◽  
Engineering Practice ◽  
Characteristic Vibration ◽  
Natural Parameter ◽  
Mode Localization ◽  
Vibration Localization ◽  
Natural Characteristic

The mistuning of periodic structure was generally considered to be natural parameter mistuning, such as stiffness mistuning, damping mistuning and mass mistuning. However, in engineering practice, there was another kind of mistuning——force mistuning, which has not been studied yet. Based on a typical concentrated parameter model of periodic structure, the vibration characteristics, such as natural characteristic, vibration mode and vibration localization of periodic structure with different mistuning forms, were compared and analyzed. The results show that, as a new mistuning form, force mistuning won’t bring mode localization, while it could lead to vibration response localization

A New Mistuning Form Existed in Periodic Structure-Force Mistuning

2012 ◽  
Vol 229-231 ◽  
pp. 377-381
Author(s):  
Ai Lun Wang ◽  
Jie Chen ◽  
Qian Jin Wang
Keyword(s):  
Periodic Structure ◽  
Vibration Mode ◽  
Structure Design ◽  
Engineering Practice ◽  
Characteristic Vibration ◽  
Natural Parameter ◽  
Mode Localization ◽  
Vibration Localization ◽  
Natural Characteristic ◽  
Design And Manufacture

The mistuning of periodic structure was generally considered to be natural parameter mistuning, such as stiffness mistuning, damping mistuning and mass mistuning. However, in engineering practice, there was another kind of mistuning—force mistuning. Based on a typical concentrated parameter model of periodic structure, the vibration characteristics, such as natural characteristic, vibration mode and vibration localization of periodic structure with different mistuning forms, were compared and analyzed. The results show that, as a new mistuning form, force mistuning won’t bring mode localization, while it could lead to vibration response localization. The results are very important for periodic structure design and manufacture.

Effect of Bladed Packets on Transient Vibration Localization Behaviors of Mistuned Whole Bladed Disk System

2021 ◽  
Author(s):  
Xuanen Kan
Keyword(s):  
Mathematical Model ◽  
Steady State ◽  
Vibration Characteristics ◽  
Vibration Response ◽  
Vibration Energy ◽  
Disk System ◽  
Transient Vibration ◽  
Vibration Localization ◽  
Bladed Disk ◽  
Alternative Approach

Abstract The multi-packets whole bladed disks are usually used in the turbo-machineries. The most different characteristic of the multi-packets whole bladed disk is that some blades are connected by lacing forming a bladed packet, and several bladed packets are assembled to form a multi-packets whole bladed disk system. Mistuning of blades is an attractive vibration subject due to vibration localization problems that vibration energy focuses on some blades. The vibration localization characteristics of steady state of bladed disk are mainly discussed in previous studies, and few works focus on the transient vibration localization behaviors of the multi-packets whole mistuned bladed disk. Transient vibration characteristics of bladed disk are crucial during startup. Therefore, in this paper, transient vibration characteristics of the multi-packets whole bladed disk are studied. A developed mathematical model is used to calculate the transient vibration response of the multi-packets whole bladed disk. The number of bladed packets on the transient vibration localization of the multi-packets mistuned whole bladed disk is discussed. The results indicate that the bladed packets are able to reduce the transient vibration localization. The results suggest that the bladed packet is an alternative approach to reduce the vibration localization of bladed disk caused by mistuning. Moreover, the different number of bladed packets will produce various behaviors of transient vibration localization of multi-packets whole mistuned bladed disk system.

Vibration Localization in Band/Wheel Systems: Theory and Experiment

1993 ◽  
Author(s):  
A. A. N. Al-jawi ◽  
A. G. Ulsoy ◽  
Christophe Pierre
Keyword(s):  
Simple Model ◽  
Coupling Model ◽  
Complex Model ◽  
Translation Speed ◽  
Mode Localization ◽  
Vibration Localization ◽  
Natural Modes ◽  
Theoretical Predictions ◽  
Axially Moving Beams ◽  
Axially Moving

Abstract An investigation of the localization phenomenon in band/wheel systems is presented. The effects of tension disorder, interspan coupling, and translation speed on the confinement of the natural modes of free vibration are investigated both theoretically and experimentally. Two models of the band/wheel system dynamics are discussed; a simple model proposed by the authors [1] and a more complete model originally proposed by Wang and Mote [9]. The results obtained using the simple interspan coupling model reveal phenomena (i.e., eigenvalue crossings and veerings and associated mode localization) that are qualitatively similar to those featured by the more complex model of interspan coupling, thereby confirming the usefulness of the simple coupling model. The analytical predictions of the two models are validated by an experiment. A very good agreement between the experimental results and the theoretical ones for the simple model is observed. While both the experimental observations and the theoretical predictions show that a beating phenomenon takes place for ordered stationary and axially moving beams, beating is destroyed (indicating the occurrence of localization) when any small tension disorder is introduced especially for small interspan coupling (i.e., when localization is strongest).

Study on Flow-Induced Vibration Characteristics of Hydraulic Hoist of Large-Span Upwelling Radial Steel Gate

2011 ◽  
Vol 117-119 ◽  
pp. 241-246
Author(s):  
Zhen Hai Gao ◽  
Gen Hua Yan ◽  
Peng Liu ◽  
Fa Zhan Chen ◽  
Fei Ming Lv
Keyword(s):  
Dynamic Characteristics ◽  
Vibration Characteristics ◽  
Vibration Response ◽  
Flow Induced Vibration ◽  
Structural Dynamic ◽  
Large Span ◽  
Response Characteristics ◽  
Lever Action ◽  
Structural Dynamic Characteristics ◽  
Steel Gate

In this paper we conduct study on flow-induced vibration of large-span upwelling radial steel Gate and its hydraulic hoist. Place an emphasis on vibration response characteristics under two working conditions of diversion and drainage, which proves the safety of hydraulic hoist gate vibration caused by gate vibration. Firstly, we study on dynamic characteristics of fluid-structure interaction of association system of gate and start and stop lever, reveals the discipline of the effect fluid having on structural dynamic characteristics. On this basis, flow-induced vibration characteristics under two conditions of with and without start and stop lever action considered. The results indicate that the gate vibration response with hydraulic hoist used decreases, which explains start and stop lever has certain effect of restraining vibration on gate vibration. In addition, under the working condition of drainage the vibration magnitude of start and stop lever is smaller than that of gate body, which explains there is damping action during transference of gate vibration through start and stop lever. The results find out that on the assumption of optimized gate structure and hydraulic arrangement, it is practicable, safe and reliable to adopt hydraulic hoist. The achievement has directive significance on similar projects construction in the future

scholarly journals Free Vibration Characteristics of Cylindrical Shells Using a Wave Propagation Method

2001 ◽  
Vol 8 (2) ◽  
pp. 71-84 ◽  
Author(s):  
A. Ghoshal ◽  
S. Parthan ◽  
D. Hughes ◽  
M.J. Schulz
Keyword(s):  
Cylindrical Shell ◽  
Wave Propagation ◽  
Free Vibration ◽  
Periodic Structure ◽  
Natural Frequencies ◽  
Vibration Characteristics ◽  
Structural Element ◽  
Lower Bounding ◽  
Nodal Points ◽  
Wave Propagation Method

In the present paper, concept of a periodic structure is used to study the characteristics of the natural frequencies of a complete unstiffened cylindrical shell. A segment of the shell between two consecutive nodal points is chosen to be a periodic structural element. The present effort is to modify Mead and Bardell's approach to study the free vibration characteristics of unstiffened cylindrical shell. The Love-Timoshenko formulation for the strain energy is used in conjunction with Hamilton's principle to compute the natural propagation constants for two shell geometries and different circumferential nodal patterns employing Floquet's principle. The natural frequencies were obtained using Sengupta's method and were compared with those obtained from classical Arnold-Warburton's method. The results from the wave propagation method were found to compare identically with the classical methods, since both the methods lead to the exact solution of the same problem. Thus consideration of the shell segment between two consecutive nodal points as a periodic structure is validated. The variations of the phase constants at the lower bounding frequency for the first propagation band for different nodal patterns have been computed. The method is highly computationally efficient.

VIBRATION CHARACTERISTICS OF PERIODIC STRUCTURE WITH MICRO OCTAGON-LIKE UNIT CELL

Mechanika ◽  
2012 ◽  
Vol 18 (1) ◽  
Author(s):  
Yulin Mei ◽  
Xiaoming Wang ◽  
Xiaofeng Wang ◽  
Peng Liu
Keyword(s):  
Periodic Structure ◽  
Vibration Characteristics ◽  
Unit Cell

VIBRATION PROPERTIES OF TRADITIONAL MASONRY WALLS OF CORTES CHURCH

2016 ◽  
Vol 3 (2) ◽  
Author(s):  
Noriko Takiyama ◽  
Akari Yamaguchi ◽  
Kohei Hara ◽  
Verdejo Juan Ramon Jimenez
Keyword(s):  
Natural Frequency ◽  
Structural Property ◽  
Vibration Mode ◽  
Vibration Characteristics ◽  
Masonry Walls ◽  
Material Thickness ◽  
Vibration Properties ◽  
Microtremor Measurement ◽  
The Church ◽  
Microtremor Measurements

The Santo Niño Church in Bohol Island was partially damaged in the Bohol Earthquake in October 2013. In this study, we investigated the structural property of the Santo Niño Church to understand the vibration characteristics of Philippine masonry constructions by checking the main damage and conducting measurement surveys and microtremor measurement on the structure and ground. The major findings of this study can be summarized as follows: (a) Collapsed walls, peeling wall stone, corner deformation, and collapsed ceiling were the main damages that were observed. The collapsed wall was measured, and the make-up and material thickness of the wall was verified. (b) By performing microtremor measurements on the walls, the vibration property of the church, such as the natural frequency and vibration mode of the longest wall A was clarified. The 1st natural frequency of the longest wall A is the lowest.

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