New Nonlinear Bushing Model for General Excitations Using Bouc-Wen Hysteretic Model

옥진규,유완석,손정현 한국자동차공학회 2008 International journal of automotive technology Vol.9 No.2

Because the characteristics of rubber bushing significantly affect the accuracy of vehicle dynamics simulations, they should be accurately modeled in the vehicle suspension model. In this paper, a new nonlinear bushing model for automotive bushing components is developed to improve the accuracy of vehicle dynamics analysis. Bushing components were first tested to capture the nonlinear and hysteretic behavior of typical elements by using a MTS 3-axis elastomer tester. A simple Bouc-Wen hysteretic differential model was modified to generate a more precise rubber bushing model. A sine wave, step input, and random excitations are imposed on the bushing. The ADAMS program is used to calculate sensitivity and the VisualDOC program is employed to find the optimal parameters for the bushing model. An error function is designed to find optimal parameters of the model. Parameter identification is carried out to satisfy the static and dynamic characteristics due to sine and step excitation inputs. It was proved that the proposed model could predict the bushing forces under sine, step, and random inputs well. The errors are within 10% in the overall range. To show the validity of the proposed model, a numerical example was also carried out. Because the bushing forces due to random excitation input show good agreement with experiments, the proposed bushing model is available in the vehicle dynamics simulation. Because the characteristics of rubber bushing significantly affect the accuracy of vehicle dynamics simulations, they should be accurately modeled in the vehicle suspension model. In this paper, a new nonlinear bushing model for automotive bushing components is developed to improve the accuracy of vehicle dynamics analysis. Bushing components were first tested to capture the nonlinear and hysteretic behavior of typical elements by using a MTS 3-axis elastomer tester. A simple Bouc-Wen hysteretic differential model was modified to generate a more precise rubber bushing model. A sine wave, step input, and random excitations are imposed on the bushing. The ADAMS program is used to calculate sensitivity and the VisualDOC program is employed to find the optimal parameters for the bushing model. An error function is designed to find optimal parameters of the model. Parameter identification is carried out to satisfy the static and dynamic characteristics due to sine and step excitation inputs. It was proved that the proposed model could predict the bushing forces under sine, step, and random inputs well. The errors are within 10% in the overall range. To show the validity of the proposed model, a numerical example was also carried out. Because the bushing forces due to random excitation input show good agreement with experiments, the proposed bushing model is available in the vehicle dynamics simulation.

Electrical insulation design and evaluation of 60kV prototype condenser cone bushing for the superconducting equipment

Shin, W.J.,Lee, J.G.,Hwang, J.S.,Seong, J.K.,Lee, B.W. North-Holland 2013 Physica. C, Superconductivity Vol.494 No.-

A cryogenic bushing is an essential component to be developed for commercial applications of high voltage (HV) superconducting devices. Due to the steep temperature gradient of the ambient of cryogenic bushing, general gas bushing adopting SF6 gas as an insulating media could not be directly used due to the freezing of SF6 gas. Therefore, condenser type bushing with special material considering cryogenic environment would be better choice for superconducting equipment. Considering these circumstance, we focused on the design of condenser bushing made of fiber reinforced plastic (FRP). In case of the design of the condenser bushing, it is very important to reduce the electric field intensification on the mounted flange part of the cryostat, which is the most vulnerable part of bushings. In this paper, design factors of cryogenic bushing were analyzed, and finally 60kV condenser bushing was fabricated and tested. In order to achieve optimal electric field configuration, the configuration of condenser cone was determined using 2D electric field simulation results. Based on the experimental and the analytical works, 60kV FRP condenser bushing was fabricated. Finally, the fabricated condenser bushing has been tested by applying lightning impulse and AC overvoltage test. From the test results, it was possible to get satisfactory results which confirm the design of cryogenic bushing in cryogenic environment.

EXPERIMENTAL STUDY ON THE BUSHING CHARACTERISTICS UNDER SEVERAL EXCITATION INPUTS FOR BUSHING MODELING

Ok, J.K.,Yoo, W.S.,Sohn, J.H. The Korean Society of Automotive Engineers 2007 International journal of automotive technology Vol.8 No.4

The bushing element shows nonlinear characteristics in both displacements and frequencies, also with hysteretic responses for repeated vibrational excitations. Since the characteristics of the rubber bushing significantly affects the accuracy of the vehicle dynamic simulation result, it should be accurately modeled in the vehicle suspension model. To develop an accurate bushing model for vehicle dynamics analysis, the bushing characteristics under several excitation inputs must be known. In this paper, a 3-axis tester was used to capture the bushing characteristics. The random inputs, sine inputs, and step inputs were imposed on each axis of the bushing. Also, two-axis inputs, the radial-axial and radial-normal inputs, were simultaneously imposed on the tester. Three-axis inputs including the radial-axial-normal direction were supplied to the tester. Bushing characteristics of each case were precisely analyzed. These results could be available for dynamic modeling of bushing.

Comparison of Semi-Physical and Black-Box Bushing Model for Vehicle Dynamics Simulation

Jeong-Hyun Sohn,Seung-Kyu Lee,Jin-Kyu Ok,Wan-Suk Yoo 대한기계학회 2007 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.21 No.2

Since bushing components have highly nonlinear characteristics according to the amplitude and the frequency, it is hard to derive a mathematical modeling of the bushing. In this paper, a semi-physical bushing model and a black-box bushing model are derived and compared. A Bone-Wen hysteretic model is employed to derive a semi-physical model and an artificial neural network algorithm is used to make a black-box bushing model. A 3-axes MTS rubber test machine is used to capture the bushing characteristics. Sine excitation tests based on the different frequencies and different amplitudes are performed to find out the bushing characteristics. Random test results are also used to generate the coefficients of a semi-physical model and weighting factors of the black-box model. Random simulations are carried out to verify the bushing models and the results are compared with each other according to the numerical efficiency and accuracy.

Frequency And Time Domain Characteristics Analysis Of Hydraulic Bushing

Nguyen Van Quyet,Yeongman Kim(김영만),Yangsu Kim(김양수),Seongbum Lee(이성범),Heungseob Kim(김흥섭) 대한기계학회 2017 대한기계학회 춘추학술대회 Vol.2017 No.11

Recently the hydraulic bushings in suspension and sub-frame system of a rear-wheel driving vehicle are adapted to improve ride quality and reduce noise and vibration. The dynamic stiffness and damping properties of these hydraulic bushings are highly dependent on the amplitude and frequency of excitation force as well as the static load, but analytical case studies about such dynamic responses are not enough. The dynamic stiffness and loss angle of a hydraulic bushing are a crucial purpose functions and it is significant to investigate the relation between the design parameter of internal structure and these functions. During the design stage of a hydraulic bushing with one fluid element, it is not easy to adjust the maximum frequency of loss angle to specific frequency of the most disruptive excitations due to geometry limitations of the fluid track. In this study, the design factors such as fluid flow passage, internal chamber are selected to affect the dynamic characteristics of hydraulic bushing. And the analytical study is implemented in several hydraulic bushing configurations with different combination of design factors. The formulation with lumped parameter model about hydraulic bushing configurations is implemented and the variation of dynamic stiffness and loss angle is examined with MATLAB simulation in time and frequency domain. Finally the feasible and practical modeling method of hydraulic bushing will be proposed.

내부쉴드 구조에 따른 컴팩트한 폴리머 부싱 설계에 관한 연구

조한구,유대훈,강형경,Cho, Han-Goo,Yoo, Dae-Hoon,Kang, Hyung-Kyung 한국전기전자재료학회 2009 전기전자재료학회논문지 Vol.22 No.5

This paper describes a study on the design of compact polymer bushing with inner control shield. In the bushing, a high electric stress occurred between field shaper and central conductor by the closely space. Also coaxial cylindrical shield has a great height along the axis to control an electric field. Consequently, all the potentials are raised axially along the field shaper and electric stress is concentrated on a part of the surface of the FRP tube near the upper end of the field shaper. In accordance, the field control can be achieved by means of the designs of such inner control shields. The floating and ring shield designs was decreased electric field concentration at critical parts of the bushing. The shield gaps is formed between field shaper and ring shield. Accordance equipotential lines extend through gaps. As a result, the resulting electrical stress are thus reduced in the range $17{\sim}23%$ in the bushing with floating and ring shield designs. Maxwell 2D simulator based on the boundary element method was also introduced in order to verify the reliability of the polymer bushing. The optimized design uses internal elements for electric stress grading at critical parts of the bushing.

A Study of a Nonlinear Viscoelastic Model for Elastomeric Bushing in Radial Mode

Seong Beom Lee,Jong-Keun Choi,Je-Hong Min 한국정밀공학회 2004 International Journal of Precision Engineering and Vol.5 No.2

An elastomeric bushing is a device used in automotive suspension systems to reduce the load transmitted from the wheel to the frame of the vehicle. The relation between the load applied to the shaft or sleeve and the relative displacement of elastomeric bushing is nonlinear and exhibits features of viscoelasticity. A load-displacement relation for elastomeric bushing is important for dynamic numerical simulations. A boundary value problem for the bushing response leads to the load-displacement relation, which requires complex calculations. Therefore, by modifying the constitutive equation for a nonlinear viscoelastic incompressible material developed by Lianis, the data for the elastomeric bushing material was obtained and this data was used to derive the new load-displacement relation for radial response of the bushing. After the load relaxation function for the bushing was obtained from the step displacement control test, Pipkin-Rogers model was developed. Solutions were allowed for comparison between the results of the modified Lianis model and those of the proposed model. It was shown that the proposed Pipkin-Rogers model was in very good agreement with the modified Lianis model.

A Study of a Nonlinear Viscoelastic Model for Elastomeric Bushing in Radial Mode

Lee, Seong-Beom,Park, Jong-Keun,Min, Je-Hong Korean Society for Precision Engineering 2004 International Journal of Precision Engineering and Vol.5 No.2

An elastomeric bushing is a device used in automotive suspension systems to reduce the load transmitted from the wheel to the frame of the vehicle. The relation between the load applied to the shaft or sleeve and the relative displacement of elastomeric bushing is nonlinear and exhibits features of viscoelasticity. A load-displacement relation for elastomeric bushing is important fur dynamic numerical simulations. A boundary value problem fur the bushing response leads to the load-displacement relation, which requires complex calculations. Therefore, by modifying the constitutive equation for a nonlinear viscoelastic incompressible material developed by Lianis, the data for the elastomeric bushing material was obtained and this data was used to derive the new load-displacement relation for radial response of the bushing. After the load relaxation function for the bushing was obtained from the step displacement control test, Pipkin-Rogers model was developed. Solutions were allowed for comparison between the results of the modified Lianis model and those of the proposed model. It was shown that the proposed Pipkin-Rogers model was in very good agreement with the modified Lianis model.

유압식 부싱의 주파수 및 시간특성의 이론적 해석

강희삼(Heesam Gang),Nquyen Van Quyet,강준복(Joonbok Gang),손현철(Hyunchul Son),이성범(Seongbeom Lee),부광석(Kwangsuk Boo),김흥섭(Heungseob Kim),윤득선(Duksun Yun) 한국자동차공학회 2016 한국자동차공학회 부문종합 학술대회 Vol.2016 No.5

Recently the hydraulic bushings in suspension and sub-frame system of a rear-wheel driving vehicle are adapted to improve ride quality and reduce noise and vibration. The dynamic stiffness and damping properties of these hydraulic bushings are highly dependent on the amplitude and frequency of excitation force as well as the static load, but analytical case studies about such dynamic responses are not enough. The dynamic stiffness and loss angle of a hydraulic bushing are a crucial purpose functions and it is significant to investigate the relation between the design parameter of internal structure and these functions. During the design stage of a hydraulic bushing with one fluid element, it is not easy to adjust the maximum frequency of loss angle to specific frequency of the most disruptive excitations due to geometry limitations of the fluid track. In this study, the design factors such as fluid flow passage, internal chamber, and internal stopper are selected to affect the dynamic characteristics of hydraulic bushing. And the analytical study is implemented in several hydraulic bushing configurations with different combination of design factors. The formulation with lumped parameter model about hydraulic bushing configurations is implemented and the variation of dynamic stiffness and loss angle is examined with MATLAB simulation in time and frequency domain. Finally the feasible and practical modeling method of hydraulic bushing will be proposed.

변압기 부싱 절연유 분해가스 발생 특성 연구

전태현,곽병섭,김아름,임병훈,박현주 대한전기학회 2025 전기학회논문지 Vol.74 No.2

In recent years, the number of failures caused by oil impregenated paper(OIP) bushings applied to long-term power transformers has been increasing, and some of them have progressed to fires, increasing the possibility of facility damage. As OIP bushings are more than 70% of the long-term bushings in operation, there is a high probability of fire in case of failure, so it is necessary to develop diagnostic technology for aging bushings. Although KEPCO is implementing insulation oil gas analysis to prevent the continued occurrence of failures and recurrence of failures due to bushing insulation breakdown. However, since KEPCO currently does not have its own bushing oil gas maintenance standards, it is necessary to establish management standards that reflect the differences in insulation oil types among manufacturers. Therefore, in this study, we evaluated the generation characteristics of major decomposed gases by failure type based on KEPCO's accumulated bushing dissolved gas analysis database for major bushing manufacturers in operation, bushing internal dismantling inspection, and accelerated aging experiments for each manufacturer. Based on this, it is expected to contribute to the establishment of abnormal diagnosis criteria for OIP bushings and improvement of facility inspection efficiency.