Recent advances in nonlinear passive vibration isolators

Tire and rim fundamentals.- Forward vehicle dynamics.- Tire dynamics.- Driveline dynamics.- Applied kinematics.- Applied mechanisms.- Steering dynamics.- Suspension mechanisms.- Applied dynamics.- Vehicle planar dynamics.- vehicle roll dynamics.- Applied vibrations.- Vehicle vibrations.- suspension optimization.- Quarter car.

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Vehicle Dynamics: Theory and Application

Structural systems often show nonlinear behavior under severe excitations generated by natural hazards. In that condition, the restoring force becomes highly nonlinear showing significant hysteresis. The hereditary nature of this nonlinear restoring force indicates that the force cannot be described as a function of the instantaneous displacement and velocity. Accordingly, many hysteretic restoring force models were developed to include the time dependent nature using a set of differential equations. This survey contains a review of the past, recent developments and implementations of the Bouc-Wen model which is used extensively in modeling the hysteresis phenomenon in the dynamically excited nonlinear structures.

The Hysteresis Bouc-Wen Model, a Survey

During the last few decades, magnetorheological (MR) elastomers have attracted a significant amount of attention for their enormous potential in engineering applications. Because they are a solid counterpart to MR fluids, MR elastomers exhibit a unique field-dependent material property when exposed to a magnetic field, and they overcome major issues faced in magnetorheological fluids, e.g. the deposition of iron particles, sealing problems and environmental contamination. Such advantages offer great potential for designing intelligent devices to be used in various engineering fields, especially in fields that involve vibration reduction and isolation. This paper presents a state of the art review on the recent progress of MR elastomer technology, with special emphasis on the research and development of MR elastomer devices and their applications. To keep the integrity of the knowledge, this review includes a brief introduction of MR elastomer materials and follows with a discussion of critical issues involved in designing magnetorheological elastomer devices, i.e. operation modes, coil placements and principle fundamentals. A comprehensive review has been presented on the research and development of MR elastomer devices, including vibration absorbers, vibration isolators, base isolators, sensing devices, and so on. A summary of the research on the modeling mechanical behavior for both the material and the devices is presented. Finally, the challenges and the potential facing magnetorheological elastomer technology are discussed, and suggestions have been made based on the authors’ knowledge and experience.

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A state-of-the-art review on magnetorheological elastomer devices

In this technical note we develop an adaptive tuned vibration absorber (ATVA) based on the unique characteristics of magnetorheological elastomers (MREs), whose modulus can be controlled by an applied magnetic field. The MRE used in the developed ATVA was prepared by curing a mixture of 704 silicon rubber, carbonyl iron particles and a small amount of silicone oil under a magnetic field. The ATVA works in shear mode and consists of an oscillator, smart spring elements with MREs, a magnet conductor and two coils. Natural frequencies of the ATVA under different magnetic fields were both theoretically analyzed and experimentally evaluated by employing a beam structure with two ends supported. The experimental results demonstrated that the natural frequency of the ATVA can be tuned from 55 to 82 Hz. The relative frequency change is as high as 147%. Furthermore, the absorption capacity of the developed ATVA can achieve as high as 60 dB, which was also experimentally justified.

https://iopscience.iop.org/article/10.1088/0964-1726/15/5/N02/pdf

Development of an adaptive tuned vibration absorber with magnetorheological elastomer

In this paper, new methods for fabricating magnetorheological (MR) elastomers are introduced. Two different MR elastomers, one made of polyurethane and the other made of natural rubber, are successfully fabricated. The experimental results show that the modulus of polyurethane MR elastomers can increase by 28% under a strong magnetic field. Comparatively, the rubber MR elastomer has low modulus change ability. A mathematical model to represent the stress-strain relationship of MR elastomers is presented. The model takes into account all the dipole interactions in a chain and the nonlinear properties of the host composite. The analytical results of the model are in agreement with experimental data.

Experimental Research and Modeling of Magnetorheological Elastomers

In this paper we review essential aspects in- volved in the design of an active vibration control system. We present a generic procedure to the design process and give selective examples from the literature on relevant ma- terial. Together with examples of their applications, various topics are briefly introduced, such as structure modeling, model reduction, feedback control, feedforward control, con- trollability and observability, spillover, eigenstructure assign- ment (pole placement), coordinate coupling control, robust control, optimal control, state observers (estimators), intelli- gent structure and controller, adaptive control, active con- trol effects on the system, time delay, actuator-structure interaction, and optimal placement of actuators.

Active Structural Vibration Control: A Review

Optimal design of passive linear suspension using genetic algorithm

Three semi-active control methods are investigated for use in a suspension system using a commer- cial magnetorheological damper. The three control methods are the limited relative displacement method, the modified skyhook method, and the modified Rakheja-Sankar method. The method of averaging has been adopted to provide an analytical platform for analyzing the performance of the different control methods. The analytical results are verified using numerical simulation, and further are used to assess the efficiency of dif- ferent control methods. An experimental test bed has been developed to examine the three control methods under sinusoidal and random excitations. Both analytical and experimental results confirm that the Rakheja- Sankar control and modified skyhook control methods significantly reduce the root-mean-square response of both the acceleration and relative displacement of the sprung mass, while the limited relative displacement controller can only control the relative displacement of the suspension system.

Semi-active Vibration Control Schemes for Suspension Systems Using Magnetorheological Dampers

This paper presents a real-time orientation estimation algorithm based on signals from a low-cost inertial measurement unit (IMU). The IMU consists of three MEMS accelerometers and three MEMS rate gyros. This approach is based on relationships between the quaternion representing the platform orientation, the measurement of gravity from the accelerometers, and the angular rate measurement from the gyros. Process and measurement models are developed, based on these relations, in order to implement them into an extended Kalman filter. The performance of each filter is evaluated in terms of the roll, pitch, and yaw angles. These are derived from the filter output since this orientation representation is more intuitive than the quaternion representation. Extensive testing of the filters with simulated and experimental data show that the filters perform very accurately in the roll and pitch angles, and even significantly corrects the yaw angle error drift.

M. F. Golnaraghi

Papers

Experimental Research and Modeling of Magnetorheological Elastomers

Active Structural Vibration Control: A Review

Optimal design of passive linear suspension using genetic algorithm

Semi-active Vibration Control Schemes for Suspension Systems Using Magnetorheological Dampers

A quaternion-based orientation estimation algorithm using an inertial measurement unit