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

Abstract

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.

Accuracy improvement method for dynamic substructuring models in vehicle systems

“…Figure 15 shows the estimated dynamic characteristics at a coupling point when the suspension was combined with the actual vehicle body. The results obtained without considering the GCPs are clearly less accurate (Figure 15), whereas using the GCPs leads to improved accuracy compared with previously obtained results using FBS methods in practical cases (Kang et al, 2019a(Kang et al, , 2019b.…”

“…Despite many studies on model improvement, practical limitations remain when applying the DS technique in automotive fields. Van der Seijs et al (2017) performed a practical physical study using the substructuring technique, and Kang (2019a, 2019b) and Song et al (2016) proposed a test jig to develop a vehicle suspension system by applying a DS technique while acknowledging the limitations of practical testing. Kim et al (2020) estimated system characteristics using virtual parameters and suggested practical uses for the DS method.…”

FRF of a coupled geared system using the frequency based substructuring and condensation methods

“…Some techniques of Frequency Based Sub-structuring (FBS), like coupling method, were suggested in Roy and Craig, 1 Tsai et al 2 Similar to coupling strategies, the decoupling techniques are created for a known assembled system to detect one of the subsystems. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] Usually, the methodology of DS as coupling method is implemented to finite element models with high number of DoFs. [7][8][9] Nevertheless the methodology of DS is applied for transmission systems to be decoupled using additional knowledge of interface characteristics.…”

“…The impact of the additional DoFs localization on the method performance is investigated in D'Ambrogio and Fregolent. 4 An evaluation of the FBS and modal synthesis technique, implemented to vehicle finite element data, were developed in Cuppens et al 13 Recently, Kang et al 12 used the inverse sub-structuring method for a suspension system.…”

A receptance-based method for frequency assignment via coupling of subsystems

“…Although CMS was proposed earlier than FBS, FBS has recently attracted more attention than CMS since FBS is able to use measured FRFs directly, and CMS techniques encounter a number of difficulties in their implementation in practice, for instance, a sufficient number of modes of the substructures has to be considered in order to accurately approximate the motion of the coupled system and the issue of modal truncation has to be dealt with. FBS-based methods are widely applied in the noise, vibration, and harshness (NVH) problems in vehicles [14], and the receptance coupling method proposed by Jetmundsen et al [15] is possibly the most common and widely implemented FBS method in the frequency domain. A well-known application of the method, which is the so-called receptance coupling substructure analysis (RCSA), has been applied to the prediction of chatter-free cutting conditions in milling machines [16,17] and the identification of joint parameters [18,19].…”