Operational modal analysis based dynamic parameters identification in milling of thin-walled workpiece

2022 ◽  
Vol 167 ◽  
pp. 108469
Author(s):  
Dongsheng Liu ◽  
Ming Luo ◽  
Zhao Zhang ◽  
Yuan Hu ◽  
Dinghua Zhang
Keyword(s):  
Modal Analysis ◽  
Operational Modal Analysis ◽  
Parameters Identification ◽  
Dynamic Parameters ◽  
Thin Walled

A time-synchronous-subtraction method for harmonics elimination in the operational modal analysis of machine tools

2019 ◽  
Vol 233 (17) ◽  
pp. 6099-6111
Author(s):  
Zhaoshun Liang ◽  
Shuting Wang ◽  
Chao Qin ◽  
Chunhui Li ◽  
Xuchu Jiang ◽  
...  
Keyword(s):  
Modal Analysis ◽  
Machine Tools ◽  
Time Synchronization ◽  
Operational Modal Analysis ◽  
Modal Parameters ◽  
Cutting Condition ◽  
Dynamic Parameters ◽  
Subtraction Method ◽  
Operational Conditions ◽  
Periodic Components

In high-precision machining, it is very important to obtain operational modal parameters of machine tools to ensure the quality of machined parts. More specifically, the prediction of free chatter boundary is a critical requirement for improving productivity, which requires accurate dynamic parameters under operational conditions. Operational modal analysis is an effective method to estimate dynamic parameters of the tested system. However, for machine tools, the direct application of the operational modal analysis method is not feasible. In measured responses, periodic components are very preponderant during cutting, which is mainly caused by the periodic cutting force. In order to overcome this issue and to extract operational modal parameters of machine tools, the method of time-synchronous-subtraction based on the principle of time-synchronization-averaging is proposed. The correctness of the proposed approach is demonstrated by a simulation experiment, and the feasibility is verified through a milling experiment. The results show that the time-synchronous-subtraction method can well eliminate harmonics in the vibration response under the real cutting condition. The method is not only accurate but also simple in calculation.

scholarly journals Obtaining Dynamic Parameters by Using Ambient Vibration Recordings on Model of The Steel Arch Bridge

2021 ◽  
Author(s):  
Azer A. Kasimzade ◽  
Sertaç Tuhta ◽  
Furkan Günday ◽  
Hakan Aydın
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Modal Analysis ◽  
Dynamic Characteristics ◽  
Operational Modal Analysis ◽  
Ambient Vibration ◽  
Mode Shapes ◽  
Dynamic Parameters ◽  
Analysis Method ◽  
Arch Bridge

Operational Modal Analysis (OMA) is a one of the most popular method to extract the dynamic characteristics from ambient vibration response signals. In this study, the dynamic characteristics of a model of steel arch bridge with a bolt connection constructed in a 6.10 m span and 1.88 m height laboratory were determined by finite element method and operational modal analysis methods. Firstly, finite element model was created in SAP2000 software of model steel system and dynamic characteristic were obtained numerically. Then, accelerometers were placed where the displacements are high on points of the system and dynamic characteristics were determined by operational modal analysis method. The aim of this study is to obtain the dynamic parameters (frequency, damping ratio, mode shapes) of the model of the steel arch bridge accurately and reliably by operational modal analysis method by making use of ambient vibrations in the laboratory conditions. For this purpose, analytical analysis of the model of the steel arch bridge with finite element method and the dynamic parameters obtained as a result of the operational modal analysis of the model steel arch bridge were compared. Also, the modal assurance criterion (MAC) was used. Good compatibility was recognized between the results obtained for experimental and numerical procedures in terms of both the natural frequency and the mode of vibration. At the end of this study, reasonable correlation is obtained between mode shapes, frequencies and damping ratios. Analytical and Operational modal frequencies differences between 0.139 %–7.170 %.

Response and Operational Modal Analysis from Wind Tunnel Test of the EOLO Flexible Aircraft

2021 ◽  
Author(s):  
David F. Castillo Zuñiga ◽  
Alain Giacobini Souza ◽  
Roberto G. da Silva ◽  
Luiz Carlos Sandoval Góes
Keyword(s):  
Wind Tunnel ◽  
Modal Analysis ◽  
Wind Tunnel Test ◽  
Operational Modal Analysis ◽  
Flexible Aircraft
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