Simplified transfer function approach for modeling frequency dependency of damping characteristics of rubber bushings

Abstract

Physical systems that consist of parts and vibration isolators such as rubber bushings are usually modeled in multibody simulations, where parts are represented as rigid bodies with their mass and inertia properties and rubber bushings are modeled with Voigt models to represent their stiffness and damping characteristics. Employment of Voigt models in multi-degree-of-freedom systems, however, may result in lower accuracy due to limitations in representing frequency-dependent dynamic characteristics of vibration isolators. To overcome this challenge, in this study, we develop and present a simplified frequency-dependent transfer function model by generating their frequency-dependent complex stiffness and damping from vehicle-level measurements. The damping characteristics of rubber bushings as a function of frequency is represented by a second-order transfer function. Three parameters of the transfer function are determined by solving an optimization problem to minimize the integral of absolute error between the measurement and simplified model’s predictions. Sequential Quadratic Programming, a gradient descent–based algorithm, is selected as the optimization algorithm for this purpose. The proposed methodology is demonstrated on a heavy commercial truck. Truck cabin is represented as a rigid body connected to four rubber bushings, which are modeled to show the frequency dependency of the damping as a simple transfer function. Simulation results are well correlated with the measurements obtained from prototype vehicle tests on various road profiles showing capability improvement over Voigt modeling approach due to a more representative damping characteristic of rubber bushings as a function of frequency. Integration of the proposed method into multibody simulation software is also demonstrated with cosimulation between MSC.ADAMS and MATLAB software.

Collaborative optimization of bushing installation angle and bushing stiffness of torsion beam suspension to improve the handing stability of the whole vehicle

“…3,4 Until now, numerous scholars have executed lots of research on the rubber bushing of various suspension. Aydemir et al 5 put forward a simplified frequencydependent transfer function model to overcome the problem of lower accuracy due to limitations in representing the frequency-dependent dynamic characteristics of vibration isolators. The proposed method is validated on centain heavy commercial truck, and the proposed model was more accurate than that modeled by Voigt.…”

Modeling and analysis of dynamic characteristics of rubber isolators for electric vehicles under high-frequency excitation

“…Rubber materials are widely used in many automotive vibration systems due to their excellent vibration isolation performance, such as powertrain mounts and rubber bushings. 1,2 Compared with traditional gasoline vehicles, the vibration and noise levels of electric vehicles are generally reduced. 3 However, with the improvement of the speed performance and load performance of the drive motor, the high-frequency vibration and noise generated by the motor begin to affect the ride comfort of electric vehicles.…”

Frequency dependence prediction and parameter identification of rubber bushing

“…Subsequently, a model describing the torsion direction of the rubber bushing is utilized in the same way 8 . Eren 9 develops a simplified frequency-dependent transfer function model which is demonstrated on a heavy commercial truck. The results show the improvement of the accuracy of the methodology compared to the Voigt model.…”