Derivation of road noise improvement factor within a suspension system using the inverse substructuring method

2019 ◽  
Vol 233 (14) ◽  
pp. 3775-3786 ◽  
Author(s):  
Yeon June Kang ◽  
Jun Gu Kim ◽  
David P Song ◽  
Kang Duck Ih
Keyword(s):  
Frequency Response ◽  
Response Function ◽  
Frequency Response Function ◽  
Dynamic Properties ◽  
Dynamic Stiffness ◽  
The Body ◽  
Road Noise ◽  
Input Force ◽  
Improvement Factor ◽  
Cross Member

This research aims to develop a method to efficiently reduce the body input force from the chassis due to road-induced excitation. To this end, the frequency response function–based substructuring method is employed to model the vehicle cross member and coupling points. Using this model, the dynamic stiffness modification factor of elastic bushing at the effective path is predicted for reducing road noise. Because of the difficulties in directly obtaining dynamic properties of body mount bushings pressured into the sub-frame, the frequency response function–based substructuring model and inverse formulation method are used to indirectly estimate the bushing’s dynamic properties. Therefore, the primary focus of this study is to validate the feasibility of using the inverse formulation method for deriving road noise improvement factor on a simple cross member application. In this feasibility validation, road excitation is simply substituted with a shaker excitation in vertical direction. The previously developed suspension rig that enables a direct measurement of the body input force at the coupling points and the specially developed cross member jig are used for the validation test.

Response Prediction and Dynamic Substructuring for Coupled Structures in the Frequency Domain

2020 ◽  
Vol 36 (6) ◽  
pp. 867-879
Author(s):  
X. H. Liao ◽  
W. F. Wu ◽  
H. D. Meng ◽  
J. B. Zhao
Keyword(s):  
Frequency Response ◽  
Response Function ◽  
Frequency Response Function ◽  
Dynamic Properties ◽  
Main Idea ◽  
Prediction Method ◽  
Response Prediction ◽  
Synthesis Methods ◽  
Dynamic Substructuring ◽  
Coupled Structures

ABSTRACTTo evaluate the dynamic properties of a coupled structure based on the dynamic properties of its substructures, this paper investigates the dynamic substructuring issue from the perspective of response prediction. The main idea is that the connecting forces at the interface of substructures can be expressed by the unknown coupled structural responses, and the responses can be solved rather easily. Not only rigidly coupled structures but also resiliently coupled structures are investigated. In order to further comprehend and visualize the nature of coupling problems, the Neumann series expansion for a matrix describing the relation between the coupled and uncoupled substructures is also introduced in this paper. Compared with existing response prediction methods, the proposed method does not have to measure any forces, which makes it easier to apply than the others. Clearly, the frequency response function matrix of coupled structures can be derived directly based on the response prediction method. Compared with existing frequency response function synthesis methods, it is more straightforward and comprehensible. Through demonstration of two examples, it is concluded that the proposed method can deal with structural coupling problems very well.

Seismic Structural Damage Detection Based on Time Frequency Response Function

2011 ◽  
Vol 219-220 ◽  
pp. 243-249
Author(s):  
Bai Sheng Wang ◽  
Lie Sun ◽  
Zhi Wei Chang
Keyword(s):  
Frequency Response ◽  
Response Function ◽  
Structural Damage ◽  
Frequency Response Function ◽  
Dynamic Properties ◽  
Response Analysis ◽  
Central Frequency ◽  
Structural Dynamic ◽  
Time Frequency ◽  
Marginal Spectrum

Considering that Hilbert-Huang Transformation (HHT) can be used to analyze instantaneous frequency in structural dynamic analysis, this paper proposes the concept of HHT marginal spectrum based time frequency response function. It also defines “central frequency”, which is used to reflect the change of structural dynamic properties during earthquakes, and discloses time-varying development of seismic structural damage. Using a three-story shear frame model, which is subjected to the El Centro seismic wave, the HHT time frequency response analysis of its acceleration response has been made, results show that the adoption of central frequency can successfully indicate the damage inception instant and its development.

Dynamic Identification of Convergent Externally Pressurized Gas-Bearing Gaps

1988 ◽  
Vol 110 (2) ◽  
pp. 263-270 ◽  
Author(s):  
P. Plessers ◽  
R. Snoeys
Keyword(s):  
Frequency Response ◽  
Response Function ◽  
Frequency Response Function ◽  
Dynamic Stiffness ◽  
Test Procedure ◽  
Dynamic Identification ◽  
Thrust Bearings ◽  
Stiffness And Damping ◽  
Air Film ◽  
Gas Bearing

The dynamic behavior of externally pressurized gas bearings is described by means of frequency response functions, from which dynamic stiffness and damping coefficients are derived. A numerical method is presented to calculate the frequency response function for plane circular thrust bearings with convergent gap geometry. A test procedure is described for measuring the frequency response function of an air film in order to verify computational, results. The comparison reveals a fairly good agreement between measured and calculated frequency responses. Finally, the effect of bearing parameters on the frequency response function of the air film is investigated.

scholarly journals Frequency response function simulation and evaluating in boring

2021 ◽  
Vol 5 (3) ◽  
Author(s):  
Maksym Shykhalieiev ◽  
Vadim Medvedev
Keyword(s):  
Frequency Response ◽  
Response Function ◽  
Phase Angle ◽  
Frequency Response Function ◽  
Dynamic Stiffness ◽  
Stability Lobe ◽  
Machining Center ◽  
Machining System ◽  
Computer Numerical Simulation ◽  
Stability Lobe Diagrams

Finite element method of simulating frequency response function (FRF) for boring tool in LS-Dyna solver is investigated in this work. Nowadays, computer numerical simulation allows to obtain FRF using different materials model with high precision compared to real experiments with sensors like impact hammer testing. This function is used in construction of stability lobe diagrams that allows operator of machining center to avoid chatter self-excited vibrations. Such vibration is led to decreasing of productivity and quality in cutting of metals and other materials. Amplitude and phase angle for the model is obtained from LS-Dyna result interpreter, that reads binary files, created during simulation by the program. Amplitude and phase angle of frequency response function are depending on dynamic stiffness of machining system. Real and imaginary part of frequency response function have been obtained during simulation. With luck of dynamic stiffness amplitudes of response increases.    

scholarly journals Using vibroacoustic methods to describe the dynamic properties of composite elements to assess their technical condition

Rail Vehicles ◽  
2021 ◽  
pp. 41-51
Author(s):  
Daniel Mokrzan ◽  
Julia Milewicz ◽  
Grzegorz Szymański
Keyword(s):  
Frequency Response ◽  
Response Function ◽  
Frequency Response Function ◽  
Dynamic Properties ◽  
Technical Condition

W artykule zaprezentowano przebieg badań oraz analizę dotyczącą możliwości wykorzystania ciśnienia akustycznego jako parametru diagnostycznego w ocenie stanu technicznego elementów wykonanych z materiałów kompozytowych. Przeprowadzono eksperyment w postaci testu impulsowego z wykorzystaniem młotka modalnego jako wzbudnika odpowiedzi wibroakustycznej układu. Wykazano, że duże wewnętrzne ubytki w strukturze powodują zmiany charakterystyki funkcji odpowiedzi częstotliwościowej (Frequency Response Function, FRF) w paśmie poniżej 8 kHz. W wyniku przeprowadzonej analizy udowodniono, że ciśnienie akustyczne może być skutecznie wykorzystywane w diagnozie elementów wykonanych z materiałów kompozytowych.

scholarly journals Моделювання амплітудно-фазової частотної функції і її оцінка при розто- чуванні

2021 ◽  
Author(s):  
Maksym Shykhalieiev ◽  
Vadim Medvedev
Keyword(s):  
Frequency Response ◽  
Response Function ◽  
Phase Angle ◽  
Frequency Response Function ◽  
Dynamic Stiffness ◽  
Stability Lobe ◽  
Machining Center ◽  
Machining System ◽  
Computer Numerical Simulation ◽  
Stability Lobe Diagrams

Finite element method of simulating frequency response function (FRF) for boring tool in LS-Dyna solver is investigated in this work. Nowadays, computer numerical simulation allows to obtain FRF using different materials model with high precision compared to real experiments with sensors like impact hammer testing. This function is used in construction of stability lobe diagrams that allows operator of machining center to avoid chatter self-excited vibrations. Such vibration is led to decreasing of productivity and quality in cutting of metals and other materials. Amplitude and phase angle for the model is obtained from LS-Dyna result interpreter, that reads binary files, created during simulation by the program. Amplitude and phase angle of frequency response function are depending on dynamic stiffness of machining system.

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