scholarly journals A modified complex modal testing technique for a rotating tire with a flexible ring model

2015 ◽  
Vol 60-61 ◽  
pp. 604-618 ◽  
Author(s):  
Jongsuh Lee ◽  
Semyung Wang ◽  
Bert Pluymers ◽  
Wim Desmet ◽  
Peter Kindt
Author(s):  
Seok-Ku Lee ◽  
Chong-Won Lee

Abstract Unidirectional excitation technique is presented for the complex modal testing of asymmetric rotor systems. The theoretical development, which is made strictly in the stationary coordinate system, enables the unidirectional excitation to effectively estimate the directional frequency response functions. It far lessens the testing efforts a numerical example of the dynamically tuned gyroscope (DTG) is treated to demonstrate the practicality of the complex modal testing.


2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Aakash Swami ◽  
Ashok Kumar Pandey

Abstract To address various tire vibration characteristics such as noise, vibration, and harshness, it is necessary to study the tire dynamic performance. In this paper, we focus on investigating the influence of static loading on radial (in-plane) and bending modes and their frequencies of a tire. To model the effect, we first identify important tire parameters, termed as modal parameters, based on three-dimensional ring model and three-dimensional finite element results under free-free conditions without and with temperature variations. After finding the parameters, we have used three-dimensional flexible ring model in which both in-plane and bending modes are considered under static loading. When load is applied, tire behavior changes and it becomes more stiffer. Thus, it fixes the tire to the road and increases the contact region. In this paper, we define this contact region over θf < θ < 2π and the region 0 < θ < θf can be considered free-free. Subsequently, we assume the expression of radial and bending modes in terms of generalized coordinates satisfying the above boundary conditions and obtain kinetic and potential energy by integrating it over 0 < θ < θf. The unknown coordinate is obtained by satisfying the governing conditions. Finally, corresponding mode shapes and frequencies are obtained. The assumed modes and frequencies are validated with three-dimensional finite element model using abaqus. The same procedure can be extended to compute modes and frequencies as a function of temperature under static loading for a constant tire pressure.


Author(s):  
Chong-Won Lee ◽  
Young-Don Joh

Abstract Various modal testing methods are proposed for the effective use of complex modal testing for rotating machinery, focusing on excitations and measurements. The proposed methods are developed, based on the input/output relationships for complex signals, for the direct or indirect assessment of frequency response and coherence functions between complex inputs and outputs. The proposed testing methods and the classical modal testing method are compared in consideration of required number of frequency response functions (FRFs) and testing efforts.


Author(s):  
Hojong Lee ◽  
Saied Taheri

Since they are believed to provide more reliable and accurate tire contact parameters, intelligent tires have been widely studied for the purpose of the performance enhancement of the vehicle control systems such as anti-lock breaking system and the electronic stability program. Moreover, it is also expected that intelligent tires can be utilized to analyze tire dynamic response, taking into consideration that the measurements from the sensors inside the tire would contain considerable information on tire behavior in real driving scenarios. In this work, the tire physical characteristics related to in-plane dynamics of the tire, such as stiffness of the belt and sidewall and contact pressure distribution, were identified based on the combination of strain measurements and a flexible ring tire model. The radial deformation of the tread band was directly obtained from strain measurements based on the strain-deformation relationship. Tire parameters were identified by fitting the radial deformations from the flexible ring model to those derived from strain measurements. This approach removed the complex and repeated procedure to satisfy the contact constraints between the tread and the road surface in the traditional ring model. For validation purposes, circumferential strains were measured for three different tires on a Flat-Trac indoor test rig. And then, circumferential contact pressures and tire parameters were estimated based on these measurements. Identification using only model-based methods was conducted and comparison was made to the measured contact patch shapes. The comparison among identification methods and measurements shows good agreement. The proposed method of utilizing intelligent tire fused with physical tire model is expected to provide another tool to investigate tire characteristics. Moreover, tire properties identified using intelligent tires could be more closely linked to vehicle performance.


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