A Robust RCSA-Based Method for the In Situ Measurement of Rotating Tool-Tip Frequency Response Functions

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Yulei Ji ◽  
QingZhen Bi ◽  
Long Yu ◽  
Fei Ren ◽  
Yuhan Wang
Keyword(s):  
Frequency Response ◽  
In Situ Measurement ◽  
Measurement Noise ◽  
Laser Vibrometer ◽  
Response Functions ◽  
Frequency Response Functions ◽  
Receptance Coupling ◽  
Tool Replacement ◽  
Receptance Coupling Substructure Analysis

Abstract Measuring rotating tool-tip frequency response functions (FRFs) is difficult because of the fluted tip geometry. The methods based on receptance coupling substructure analysis (RCSA) can obtain rotating tool-tip FRFs with a few tests. Existing RCSA-based methods require at least one smooth rod for measurement and then mathematically calculate the desired rotating tool-tip FRFs. However, involving the inverse of the experimentally obtained FRFs matrix, these methods are susceptible to the measurement noise in the rotating structure. In addition, the inconsistency between the holder–tool and holder–rod connections is another uncertainty which impacts accuracy. This paper presents a robust RCSA-based method to obtain rotating tool-tip FRFs. It is found that tool-tip FRFs can be calculated from another point FRFs on the same assembly. Then, one point on the smooth cylindrical shank of the tool is selected for measurement. The measured FRFs, along with those from the theoretical tool model, calculate the rotating tool-tip FRFs. Compared with the previous methods, the proposed one does not require inverting the measured FRFs matrix, inherently avoiding amplification of measurement noise. Since the tool replacement is no longer required, in situ measurement is achieved to ensure the same holder–tool connection throughout the procedure. The proposed method is first validated in a numerical case and then verified experimentally by a commercial hammer and laser vibrometer. Both results show that the method is insensitive to the measurement noise and can obtain rotating tool-tip FRFs with considerable accuracy.

scholarly journals Decoupling of mechanical systems based on in-situ frequency response functions: The link-preserving, decoupling method

2015 ◽  
Vol 58-59 ◽  
pp. 340-354 ◽  
Author(s):  
Laurent Keersmaekers ◽  
Luc Mertens ◽  
Rudi Penne ◽  
Patrick Guillaume ◽  
Gunther Steenackers
Keyword(s):  
Frequency Response ◽  
Mechanical Systems ◽  
Response Functions ◽  
Frequency Response Functions ◽  
Decoupling Method

scholarly journals Analyzing the Dynamic Characteristics of Milling Tool Using Finite Element Method and Receptance Coupling Method

2019 ◽  
Vol 9 (2) ◽  
pp. 3918-3923
Author(s):  
J. P. Hung ◽  
W. Z. Lin ◽  
K. D. Wu ◽  
W. C. Shih
Keyword(s):  
Finite Element ◽  
Frequency Response ◽  
Dynamic Characteristics ◽  
Coupling Method ◽  
Response Functions ◽  
Original Design ◽  
Frequency Response Functions ◽  
Feeding Mechanism ◽  
Receptance Coupling ◽  
Milling Tool

This study aims to investigate the dynamic characteristics of a milling machine with different head stocks by using finite element (FE) method and receptance coupling analysis (RCA). For this purpose, five full finite element machine models, including vertical column, reformed head stock and feeding mechanism were created. With these models, the tool point frequency response functions were directly predicted. Another approach was the application of the receptance coupling method, in which the frequency response of the assembly milling tool was calculated from the receptance components of the individual substructures through the coupling operation with the interfaces of the feeding mechanism. Results show that a whole machine model with reformed stock has superior dynamic behavior when compared with the original design, by an increment of 10% in the dynamic stiffness. The receptance coupling method was verified to show an accurate prediction of the frequency response functions of the spindle tool when compared with the results obtained from the full FE models. Overall, the proposed methodology can help the designer to efficiently and accurately develop the machine tool structure with excellent mechanical performance.

Identification of Toolholder-Spindle Joint Based on Receptance Coupling Substructure Analysis

2013 ◽  
Vol 345 ◽  
pp. 539-542
Author(s):  
Li Jun Zhai ◽  
Xiao Lei Song ◽  
Li Gang Cai
Keyword(s):  
Dynamic Response ◽  
Machine Tool ◽  
Frequency Response ◽  
Spindle Assembly ◽  
Response Functions ◽  
Identification Method ◽  
Receptance Coupling ◽  
Basic Work ◽  
Substructure Analysis ◽  
Receptance Coupling Substructure Analysis

Stiffness identification of toolholder-spindle joint is a basic work for machine tool dynamic research. In this paper, an identification method based on receptance coupling substructure analysis is described. Once the frequency response functions of the toolholder, the spindle and the toolholder-spindle assembly are obtained, the analytical stiffness could be calculated. The method is verified efficiency through dynamic response experiment. Identified stiffness results under different drawbar forces are also discussed.

Damage Localization in Composite Structures Using Nonlinear Vibration Response Properties

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Sara S. Underwood ◽  
Janette J. Meyer ◽  
Douglas E. Adams
Keyword(s):  
Composite Materials ◽  
Frequency Response ◽  
Composite Structures ◽  
Nonlinear Behavior ◽  
Subsurface Damage ◽  
Wide Area ◽  
Laser Vibrometer ◽  
Response Functions ◽  
Frequency Response Functions ◽  
Inspection Method

Subsurface damage in composite materials is difficult to detect using visual techniques, and other current inspection methods lack the ability to perform quick, wide-area inspections without the need for reference signatures or baseline measurements. This paper presents a method for detecting and locating subsurface damage in composite materials without historical reference measurements by considering the nonlinear behavior of the material in the vicinity of damage. Nonlinear behavior is identified by comparing frequency response functions measured at different input amplitudes. It will be shown that the nonlinear behavior of the material is most evident in the areas nearest to the damage. The proposed inspection method is demonstrated both analytically and experimentally. First, a finite element model of a sandwich beam is developed using Bernoulli–Euler beam elements to represent each layer of the beam and springs to represent the interface between the layers. A bilinear stiffness nonlinearity is simulated to represent disbond damage between the top and core layers of the beam. The simulated disbond damage is localized by identifying degrees of freedom which indicate significant nonlinear response through a comparison of frequency response functions measured at various input amplitudes. Next, the method is demonstrated experimentally by identifying disbond damage in a fiberglass sandwich panel. A three-dimensional scanning laser vibrometer is used to measure the forced frequency response of the panel in its damaged state as it is excited at two or more amplitudes of excitation by a piezoelectric actuator. Comparisons of the frequency response functions measured at different input amplitudes show that the subsurface damage introduces nonlinear behavior which resembles a bilinear stiffness nonlinearity, and the differences in the frequency response functions are largest in the vicinity of the damage location. In addition, it was found that improved localization of the damage is achieved by investigating the response at higher frequencies. This work has application as a nondestructive method for detecting and locating subsurface damage in composite materials and, by using a laser vibrometer for noncontact measurement, allows for quick, wide-area inspection of composite materials without the need for reference signatures or baseline measurements.

scholarly journals Identification of relevant acoustic transfer paths for WT drivetrains with an operational transfer path analysis

2021 ◽  
Author(s):  
W. Schünemann ◽  
R. Schelenz ◽  
G. Jacobs ◽  
W. Vocaet
Keyword(s):  
Path Analysis ◽  
Wind Turbine ◽  
Frequency Response ◽  
Mechanical System ◽  
Reference Point ◽  
Response Functions ◽  
Frequency Response Functions ◽  
Transfer Path ◽  
Transfer Path Analysis ◽  
Turbine Model

AbstractThe aim of a transfer path analysis (TPA) is to view the transmission of vibrations in a mechanical system from the point of excitation over interface points to a reference point. For that matter, the Frequency Response Functions (FRF) of a system or the Transmissibility Matrix is determined and examined in conjunction with the interface forces at the transfer path. This paper will cover the application of an operational TPA for a wind turbine model. In doing so the path contribution of relevant transfer paths are made visible and can be optimized individually.

Calculation of Component Mode Synthesis Matrices From Measured Frequency Response Functions, Part 2: Application

1998 ◽  
Vol 120 (2) ◽  
pp. 509-516 ◽  
Author(s):  
J. A. Morgan ◽  
C. Pierre ◽  
G. M. Hulbert
Keyword(s):  
Frequency Response ◽  
Coupled System ◽  
Companion Paper ◽  
Component Mode Synthesis ◽  
Response Functions ◽  
Frequency Response Functions ◽  
Measured Frequency ◽  
Measured Frequency Response ◽  
Coupled Beams ◽  
The Individual

This paper demonstrates how to calculate Craig-Bampton component mode synthesis matrices from measured frequency response functions. The procedure is based on a modified residual flexibility method, from which the Craig-Bampton CMS matrices are recovered, as presented in the companion paper, Part I (Morgan et al., 1998). A system of two coupled beams is analyzed using the experimentally-based method. The individual beams’ CMS matrices are calculated from measured frequency response functions. Then, the two beams are analytically coupled together using the test-derived matrices. Good agreement is obtained between the coupled system and the measured results.

Experimental Study for Extraction of Normal Modes

1995 ◽  
Author(s):  
S. Y. Chen ◽  
M. S. Ju ◽  
Y. G. Tsuei
Keyword(s):  
Frequency Response ◽  
Normal Mode ◽  
Normal Modes ◽  
Measurement Data ◽  
Mode Shapes ◽  
Complex Frequency ◽  
Response Functions ◽  
Frequency Response Functions ◽  
Incomplete System ◽  
Coupled Structures

Abstract A frequency-domain technique to extract the normal mode from the measurement data for highly coupled structures is developed. The relation between the complex frequency response functions and the normal frequency response functions is derived. An algorithm is developed to calculate the normal modes from the complex frequency response functions. In this algorithm, only the magnitude and phase data at the undamped natural frequencies are utilized to extract the normal mode shapes. In addition, the developed technique is independent of the damping types. It is only dependent on the model of analysis. Two experimental examples are employed to illustrate the applicability of the technique. The effects due to different measurement locations are addressed. The results indicate that this technique can successfully extract the normal modes from the noisy frequency response functions of a highly coupled incomplete system.

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