Transfer Path Analysis of a Vehicle Subframe: Measurements in Six Degrees of Freedom

1997 ◽  
Author(s):  
Lars Ivarsson
Keyword(s):  
Path Analysis ◽  
Transfer Functions ◽  
The Body ◽  
Impedance Method ◽  
Transfer Path ◽  
Rotational Components ◽  
Improve Measurement ◽  
Engine Mount ◽  
Six Dof ◽  
Transfer Path Analysis

Abstract A Transfer path analysis (TPA) is undertaken for a car subframe concerning six DOF of freedom and two coupling points up to 500 Hz. Integrated stingers have been developed to improve measurement results. The relative importance of the rotational components is investigated. The blocked impedance method has been used to couple the subframe to the car body using measured mobilities via two isolators out of four. The sound sensitivity is measured directly for the coupled system and compared with the total sum of the calculated transfer path components which are calculated with measured mobilities and transfer functions. Calculated and measured results show good agreement. The importance of the rotational paths depends on the characteristics of the isolator and the structures where it is mounted. It was found that the front mount position is more sensitive to rotations compared to the rear mount position. The rear mount position is also a much stiffer construction. It was found that above 220 Hz, the rotational paths are of the same importance as the translational paths when both points were connected to the body frame. It was also found that for the rear mount position, only one translational transfer path dominates. These conclusions do not differ especially for different excitation directions at the engine mount position.

scholarly journals Improved vehicle interior structure-borne noise induced by the powertrain using parallel dry friction damper

2017 ◽  
Vol 37 (2) ◽  
pp. 295-312 ◽  
Author(s):  
Eid Saber Mohamed ◽  
Shawki Abouel-Seoud ◽  
Manar Eltantawie ◽  
Abdelfattah Mohamded ◽  
Mohamed Salah
Keyword(s):  
Path Analysis ◽  
Dry Friction ◽  
Transfer Functions ◽  
The Body ◽  
Interior Noise ◽  
Interior Structure ◽  
Friction Damper ◽  
Transfer Path ◽  
Transfer Path Analysis ◽  
Noise Vibration

Because of the higher requirements for vehicle comfort and people’s increasing ecological consciousness, research on the interior noise in a vehicle has received wide attention, among which structure-borne noise is hard to diagnose. To solve the problem, the transfer path analysis method of powertrain structure-borne noise has been systematically analyzed. By introduction of the powertrain source-path-receiver model, this method enables the researchers to estimate and study the noise, vibration, and harshness transfer functions and their operational forces. The aim is to further improve noise, vibration, and harshness with minimal negative impact on other vehicle attributes, such as ride comfort, handling, drivability, durability, etc. In this article, a parallel dry friction damper was added to the vehicle nearside powertrain mount, which is the most significant one to the receiver of passenger vehicle for improving its interior structure-borne noise induced by the engine. The test vehicle was a midsize executive vehicle. Since the structure-borne noise is composed of multiple paths, then the transfer path analysis test of the vehicle was carried out, and the transfer function and operational data at speed range started from 20 to 100 km/h were obtained. On the basis of the transfer path analysis results and the above principle, the friction damper on the body side of the nearside mount is improved by combination of the experimental transfer path analysis and the final measurements. The results indicate that a significant reduction for the A-weighted sound pressure level of the interior noise has been gained when the frictional damper was added to conventional mount.

Analysis and Study of the Transmission Path Based on the Body and NVH

2013 ◽  
Vol 385-386 ◽  
pp. 272-275
Author(s):  
Xia Liu ◽  
Hua Jin Yan ◽  
Xiu Jie Liu ◽  
Xia Sun
Keyword(s):  
Path Analysis ◽  
Modal Analysis ◽  
Theoretical Basis ◽  
Exhaust System ◽  
The Body ◽  
Structural Damping ◽  
The Road ◽  
Transfer Path ◽  
Transfer Path Analysis ◽  
Noise Vibration

In the field of automotive engineering, noise and vibration in the car comes mainly from the engine and the road passed through the body, suspension, mount and exhaust system path to the car or reverberation. So this article , a model of white body transfer path analysis and research, improves the rigidity of white body, to reduce noise, vibration, and weight is reduced, and find out the resonance phenomena because of insufficient stiffness of car body, combining body CAE modal analysis results provide the theoretical basis for the optimization of structural damping.

scholarly journals Transfer Path Analysis for Semisubmersible Platforms Based on Noisy Measured Data

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4801
Author(s):  
Shuqing Wang ◽  
Huawei Han ◽  
Fushun Liu ◽  
Wei Li ◽  
Shujian Gao
Keyword(s):  
Path Analysis ◽  
Transfer Functions ◽  
State Space Model ◽  
Vibration Signals ◽  
Space Model ◽  
Transfer Path ◽  
Receiver System ◽  
New Energy ◽  
Transfer Path Analysis ◽  
Two Degree Of Freedom

A new energy transfer path analysis (TPA) method that aims to analyze the transfer path of components with characteristic frequencies in semisubmersible platform structures is proposed in this paper. Due to the complexity of semisubmersible platforms, traditional TPA methods based on measurements are no longer applicable. In the proposed method, the structure is considered to be a “source-path-receiver” system and the vibration signals from the source-points are analyzed first to determine the characteristic components. Then, the signals from the source-points and the receiver-points are decomposed by introducing a state–space model. Through correlation functions, the characteristic components can be extracted, and the transfer path can be obtained by calculating the transmissibility functions. By using transmissibility functions, the proposed method only relies on the output responses and avoids the measurement of force and transfer functions. Three examples, one numerical example containing a two-degree-of-freedom (2-DOF) model and a 5-DOF model, one experiment implemented on a barge, and the data from a dynamic positioning (DP) cabin of a semisubmersible platform were used to investigate the performance of the proposed method. The results show that the proposed method can be used to assess the transfer path quantitatively and has potential value of application in engineering.

Idle shake vibration optimization of an engine mounting system through the practical application of transfer path analysis

2020 ◽  
Vol 68 (6) ◽  
pp. 459-469
Author(s):  
E. Courteille ◽  
F. Mortier
Keyword(s):  
Path Analysis ◽  
Hybrid Approach ◽  
Measurement Data ◽  
Vibration Level ◽  
Practical Application ◽  
Idle Speed ◽  
Transfer Path ◽  
Engine Mount ◽  
Transfer Path Analysis ◽  
Idle Shake

This article presents a practical application of experimental transfer path analysis (TPA) for optimizing idle shake vibrations of a front-wheel-drive car with a transversely mounted four-cylinder diesel engine. Performance control of the vehicle engine mounting system must take into account the multiple dynamic interactions between the engine mounting system, subframe modes and the vehicle suspension. Experimental methods can be used in conjunction with simulations to design and optimize the engine mounting system. TPA is a powerful tool for the diagnosis of vibration and noise transmission via multiple solid paths. TPA allows a quick diagnosis of the engine mounting system performances on vehicle comfort. A strong synergy between numerical model and experimental data finally makes it possible to find better design alternatives, not necessarily obvious to the designer. This study is the guideline for an optimization of the engine mount noise vibration and harshness (NVH) performances by using a hybrid approach, combining an analytical approach and measurement data. First, a diagnosis of the transmission of structure-borne vibrations via the engine mounting system to the seat floor is done at constant idle speed. This method is used to rank individual engine mount contributions in the low-frequency vibration level inside the vehicle. Then, an original approach allows the optimization of the vibration level at idle speed by offsetting contributions of the engine mount paths by adding damping in the right engine mount. This approach has led to the design and validation of an original double inertia-track hydroelastic mount prototype which allows a 5-dB reduction on the seat floor vibration level. The future development of a new version is planned to confirm and optimized the obtained results. The length of the second inertia track will be increased to reach the targeted characteristics, and the adjustment system will be removed to respect the overall dimension constraints of the mount.

Transfer Path Analysis of Body Panel Participation Using a Structural-Acoustic Finite Element Model

2012 ◽  
Author(s):  
Shung H. Sung ◽  
Donald J. Nefske
Keyword(s):  
Finite Element ◽  
Path Analysis ◽  
Element Model ◽  
Operating Conditions ◽  
The Body ◽  
Interior Noise ◽  
Theoretical Development ◽  
Transfer Path ◽  
Transfer Path Analysis ◽  
Body Panel

In transportation vehicles under operating conditions, interior noise frequently results from forces transmitted through the vehicle structure that excite body panel vibrations that couple with the body modes to radiate noise to the interior. The body panel participations to the interior noise that result from the force transfer paths can be identified using acoustic and structural-acoustic finite element models of the vehicle. This paper describes the transfer path analysis method to identify the body panel and modal participations for prescribed forcing excitations to the vehicle and to evaluate the effect of structural modifications. The theoretical development of the structural-acoustic finite element method and its example applications to two automotive vehicles are presented.

scholarly journals Vibration Transfer Path Analysis and Path Ranking for NVH Optimization of a Vehicle Interior

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
B. Sakhaei ◽  
M. Durali
Keyword(s):  
Quality Assurance ◽  
Path Analysis ◽  
Critical Issue ◽  
Vehicle Interior ◽  
Noise And Vibration ◽  
Good Compliance ◽  
Transfer Path ◽  
Good Ability ◽  
Engine Mount ◽  
Transfer Path Analysis

By new advancements in vehicle manufacturing, evaluation of vehicle quality assurance has got a more critical issue. Today noise and vibration generated inside and outside the vehicles are more important factors for customers than before. So far several researchers have focused on interior noise transfer path analysis and the results have been published in related papers but each method has its own limitations. In present work, the vibration transfer path analysis and vibration path ranking of a car interior have been performed. As interior vibration is a source of structural borne noise problem, thus, the results of this research can be used to present the structural borne noise state in a vehicle. The proposed method in this paper does not need to disassemble the powertrain from the chassis. The procedure shows a good ability of vibration path ranking in a vehicle and is an effective tool to diagnose the vibration problem inside the vehicle. The simulated vibration spectrums in different speeds of the engine have a good compliance with the tested results; however, some incompatibilities exist and have been discussed in detail. The simulated results show the strength of the method in engine mount optimization.

Application of Blocked Force Methodology in NVH development of Electrical Machines

2021 ◽  
Vol 263 (3) ◽  
pp. 3417-3423
Author(s):  
Keyu Chen ◽  
Marcus Hartwig ◽  
Duane Buening ◽  
Borg Warner
Keyword(s):  
Transfer Function ◽  
Path Analysis ◽  
Transfer Functions ◽  
Electrical Machines ◽  
Function Measurement ◽  
Transfer Path ◽  
Force Method ◽  
Transfer Path Analysis ◽  
Rotor Assembly

To determine excitation forces of electrical machines from measurements, Transfer Path Analysis is commonly used. Transfer Path Analysis yields input forces indirectly utilizing measured responses and transfer functions. When conducting transfer function measurement, it is recommended that the source of excitation is mechanically isolated from the receiver structure. However, in practice this is difficult to achieve without affecting the transfer path itself. The concept of the Blocked Force method introduces blocked forces which are independent of the receiver structure, thus allowing measurement of transfer functions without isolating the source. In this research, a stator / rotor assembly is considered as the source. This assembly is bolted to a test-housing, considered as the receiver. Blocked forces are determined at the mounting locations between stator and test-canister. The correctness of the calculated blocked forces is verified by comparing the predicted and measured responses at selected target points which were not used for determining the blocked forces.

Vibration Transfer Path Analysis of Double-Layer Box for Marine Reducer

2021 ◽  
Author(s):  
Miaomiao Li ◽  
Qinwen Liu ◽  
Guanghao Dai ◽  
Weifang Chen ◽  
Rupeng Zhu
Keyword(s):  
Path Analysis ◽  
Double Layer ◽  
Transfer Path ◽  
Transfer Path Analysis
Sign in / Sign up

Export Citation Format

Share Document