Search

Magnetorheological elastomer (MRE) is known for its field-sensitive shear modulus and damping property when it is exposed to a magnetic field. It has a great potential for the development of vibration reduction devices. Many research, mostly in mechanical engineering, have been focused on different kinds of vibration absorbers and vibration isolators, however few research addresses its potential in base isolation system in civil engineering application. The objective of this paper is to pilot the design and experimental testing of a novel device, an adaptive MRE base isolator, for the development of smart base isolation system. A large-scale design of the novel device with unique laminated structure of steel and MR elastomer layers is adopted. Detailed procedures on designing such adaptive base isolator are introduced. An innovative design on the magnetic circuit, with aim to provide strong and uniform magnetic field to the multi-layer MRES, is proposed to incorporate into the device design. Experimental investigation is conducted to examine its behavior under various cycling loadings when it is applied with different current inputs. Experimental results indicated that the force increase and the stiffness increase of the novel device are about 45% and 37%, respectively. To conclude, the MR elastomer base isolator will be a promising candidate to facilitate the development of adaptive base isolation system for civil structures. © 2013 IEEE.

This paper presents a novel linear tubular permanent magnet (PM) energy harvester to scavenge energy from ambient vibrations. The proposed linear PM energy harvester consists of a mover attached with PMs and a slotted stator with build-in two-phase electromagnetic coils to induce the electromagnetic induction for converting vibrations into useful electrical energy. The magnetic circuit model of the PM harvester is built to analyze the parameters about scavenging energy and used to optimize the non-dimensional geometry factors and the structural parameters in order to maximize harvested energy under given vibration and space conditions. To confirm the design, dynamic FE simulations were conducted and compared with the analytical results. Simulation results indicate that the proposed PM harvester is able to scavenge about 100 W DC power when the RMS of vibration velocity equals to 0.4 m/s. Also, the harvested power increases as the vibration velocity increasing. © 2013 IEEE.

Finding engineering applications for a new class of smart material, magnetorheological elastomer (MRE), has been a major task for researchers in this field. Novel MRE devices, such as vibration absorbers and vibration isolators, have been proposed and fabricated to pioneer its engineering applications. In civil engineering, the author has proposed a novel MRE based isolator to be used in the base isolation system for mitigating the devastating effects of earthquakes on civil structures. For any MRE-based device, electromagnetic coil is evitable involved to provide magnetic field for the MRE materials. Comparing with magnetic circuit design in magnetorheological fluid (MRF) device, i.e. MR damper, MRE devices normally need a larger coil to energize the MRE materials, particularly for a large-scale MRE device. Therefore, investigation of the solenoid on the magnetic field distribution is of great importance for the design and development of MRE based device. In particular, provision of sufficient and uniform magnetic field is essential towards the success in designing MRF/MRE devices. To understand the mechanism of magnetic field generation in a solenoid is the key for device design and optimization. The main objective of this paper is to analytically investigate and experimentally validate the magnetic field distribution in a solenoid. The theoretical investigation starts from the analysis on an ideally thin cylindrical solenoid in order to obtain analytical results. To stimulate the coil which can be used in the design of MRE device, theoretical investigation is to conduct on a thick-wall cylindrical solenoid. Finite element analysis is also used to examine the magnetic field distribution in the solenoid. In order to verify the theoretical findings, experimental testing is conducted to acquire the magnetic field distribution in a sample solenoid. Results from analytical solution, finite element analysis and experimental testing agree very well. The findings provide valuable information for the design and optimization of the MRE device in which a solenoid is inevitably involved. Copyright © 2013 by ASME.

This paper presents a recent research breakthrough on the development of a novel adaptive seismic isolation system as the quest for seismic protection for civil structures, utilizing the field-dependent property of the magnetorheological elastomer (MRE). A highly-adjustable MRE base isolator was developed as the key element to form smart seismic isolation system. The novel isolator contains unique laminated structure of steel and MRE layers, which enable its large-scale civil engineering applications, and a solenoid to provide sufficient and uniform magnetic field for energizing the field-dependent property of MR elastomers. With the controllable shear modulus/damping of the MR elastomer, the developed adaptive base isolator possesses a controllable lateral stiffness while maintaining adequate vertical loading capacity. Experimental results show that the prototypical MRE base isolator provides amazing increase of lateral stiffness up to1630%. Such range of increase of the controllable stiffness of the base isolator makes it highly practical for developing new adaptive base isolation system utilizing either semi-active or smart passive controls. To facilitate the structural control development using the adaptive MRE base isolator, an analytical model was developed to stimulate its behaviors. Comparison between the analytical model and experimental data proves the effectiveness of such model in reproducing the behavior of MRE base isolator, including the observed strain stiffening effect. Copyright © 2013 by ASME.

The major cause of failure of high voltage apparatuses is the presence of partial discharge in insulation structure. Different types of partial discharge existed in power apparatus, which will lead to breakdown of insulation. The purpose of the research work presented in this paper constitutes the issue of effective and efficient recognition of different types of partial discharges. First, partial discharge activity under AC is studied using acoustic emission technique. The wavelet technology is used to analyze acoustic signal caused by PD. Then a hybrid model which combined wavelet transform with wavelet network is proposed to classify and characteristic different types of signals. By using this method the surface, plane-plane, pin-plane, and floating discharge signal is classified effectively. Finally, to demonstrate the effectiveness of the proposed classified method, this study investigates its identification ability using 150 sets of acoustic signals generated by the PD model in insulation oil. The experiment results show that the proposed method is efficient and reliable.

Base isolation is the most popular seismic protection technique for civil engineering structures. However, research has revealed that the traditional base isolation system due to its passive nature is vulnerable to two kinds of earthquakes, i.e. the near-fault and far-fault earthquakes. A great deal of effort has been dedicated to improve the performance of the traditional base isolation system for these two types of earthquakes. This paper presents a recent research breakthrough on the development of a novel adaptive seismic isolation system as the quest for ultimate protection for civil structures, utilizing the field-dependent property of the magnetorheological elastomer (MRE). A novel adaptive seismic isolator was developed as the key element to form smart seismic isolation system. The novel isolator contains unique laminated structure of steel and MR elastomer layers, which enable its large-scale civil engineering applications, and a solenoid to provide sufficient and uniform magnetic field for energizing the field-dependent property of MR elastomers. With the controllable shear modulus/damping of the MR elastomer, the developed adaptive seismic isolator possesses a controllable lateral stiffness while maintaining adequate vertical loading capacity. In this paper, a comprehensive review on the development of the adaptive seismic isolator is present including designs, analysis and testing of two prototypical adaptive seismic isolators utilizing two different MRE materials. Experimental results show that the first prototypical MRE seismic isolator can provide stiffness increase up to 37.49%, while the second prototypical MRE seismic isolator provides amazing increase of lateral stiffness up to 1630%. Such range of increase of the controllable stiffness of the seismic isolator makes it highly practical for developing new adaptive base isolation system utilizing either semi-active or smart passive controls. © 2013 SPIE.

The partial discharge is one of the major failure mechanisms for insulation of power equipments subjected to high electrical stress. In order to understand the service conditions of insulating materials, it is very important to investigate on partial discharge characteristic in electrical apparatus. In the present paper, a set of acquisition system for acoustic signal generated by partial discharge is established in laboratory. The acoustic emission signals are generated by pinplane electrodes in oil insulation system in the voltage range of 4-6kV, the distance between electrodes and sensors in the range of 10-15cm. The test results show that voltage applied and distance between sensor and pin-plane regularly influence energy distribution of acoustic signal in different frequency component. The discrete wavelet transform is used to analyze acoustic signal acquired. A feature extraction method to classify partial discharge and a new method to identify different types of acoustic signal based on combined wavelet network and wavelet transform are respectively suggested.

Over the past few decades, wireless sensor networks have been widely used in civil structure health monitoring application. Currently, most wireless sensor networks are battery-powered and it is costly and unsustainable for maintenance because of the requirement for frequent battery replacements. As an attempt to address such issue, this paper presents a novel piezoelectric vibrational energy harvester to convert the structural vibration into usable electrical energy for powering wireless sensor networks. Unlike the normal cantilever beam structure, the piezoelectric harvester presented in this paper is based on the wafer-stack configuration which is suitable for applications where large force vibration occurs, and therefore can be embedded in civil structures to convert the force induced by vibration of large structures directly into electrical energy. The longitudinal mode of the piezoelectric wafer-stack was developed firstly to illustrate the force-to-voltage relationship of piezoelectric materials and to find the inter-medium force that will be used to convert vibration energy into electrical energy. Then, two electromechanical models (without and with a rectified circuit), considering both the mechanical and electrical aspects of the harvester, were developed to characterize the harvested electrical power under the external load. Exact closed-form expressions of the electromechanical models have been derived to analyze the maximum harvested power and the optimal resistance. Finally, a shake table experimental testing was conducted to prove the feasibility of the presented piezoelectric-wafer-stack harvester under standard sinusoidal loadings. Test results show that the harvester can generate a maximum 45mW (AC) or 16mW (DC) electrical power for sinusoidal loading with 40mm amplitude and 2Hz frequency, and the harvested electrical power is proportional to the levels of exciting vibrational loading. © 2013 SPIE.

One of the main shortcomings in current base isolation design/practice is lack of adaptability. As a result, a base isolation system that is effective for one type earthquake may become ineffective or may have adverse effect for other earthquakes. The vulnerability of traditional base isolation systems can be exaggerated by two types of earthquakes, i.e. near-field earthquakes and far-field earthquakes. This paper addresses the challenge facing current base isolation design/practice by proposing a new type of seismic isolator for the base isolation system, namely an adaptive seismic isolator. The novel adaptive seismic isolator utilizes magnetorheological elastomer (MRE) for its field-sensitive material property. Traditional seismic isolator design with a unique laminated structure of steel and MRE layers has been adopted in the novel MRE seismic isolator. To evaluate and characterize the behavior of the MRE seismic isolator, experimental testing was conducted on a shake table facility under harmonic cycling loading. Experimental results show that the proposed adaptive seismic isolator can successfully alter the lateral stiffness and damping force in real time up to 37% and 45% respectively. Based on the successful development of the novel adaptive seismic isolator, a discussion is also extended to the impact and potential applications of such a device in structural control applications in civil engineering. © 2013 IOP Publishing Ltd.

Magneto-rheological elastomer (MRE) is a new kind of smart material. Its rheological properties can be altered and controlled in a real time manner when it is applied an external magnetic field. For calculating magnetic properties of MRE material, usually Maxwell-Garnet equation is used to acquire an approximately effective permeability. This equation treats the magnetic property of particles as linear. However, when the applied magnetic field is alternating or rotating, the nonlinearity of magnetic property and magnetic hysteresis cannot be neglected. Hence, the measurement and modelling of the magnetic properties under alternating and rotating magnetic fields are essential to explore new applications of the material. This paper presents the investigation on the magnetic hysteresis properties of MRE material under one-dimensional (1-D) alternating and two-dimensional (2-D) rotating magnetic field excitations. A kind of MRE material, consisting of 70 carbonyl iron particles, 10 silicone oil, and 20 silicone rubber, was used to investigate the magnetic properties. The diameter of carbonyl iron particles is 3-5 μm. The measurement results, such as the relations between magnetic field intensity (H) and magnetic flux density (B) under different magnetic field excitations on the MRE sample, have been obtained and analyzed. These data would be useful for design and analysis of MRE smart structures like MR dampers. © 2013 American Institute of Physics.

Following a successful experimental validation of a magnetorheological elastomer (MRE) base isolator, this study presents one of the major concerns, the heating of the magnetic coil, in the design and development of the adaptive MRE based isolator. In this research, the MRE materials, with a total thickness of nearly 150 mm, are placed as the magnetic core of the device to best utilize the magnetic energy provided by the coil. A series of tests are undertaken to investigate the magnetic fields inside the coil with or without the MRE materials. Thermocouples are used to monitoring the surface temperature of the coil when it is applied with various currents for 10 min. It is shown that the measurement of field inside the solenoid when no MRE is placed inside agrees with the theoretical analysis. It is also shown that the temperature of the coil increase dramatically when a current is applied. Cooling of the coil may takes even longer, about 4 h, till down to the room temperature. Dropping of the magnetic field is observed when the temperature goes high. © Published under licence by IOP Publishing Ltd.

Base isolation is the most popular seismic protection technique for civil structures. However, research has revealed that the traditional base isolation system is vulnerable to both kinds of earthquakes, i.e. the near-fault and far-fault earthquakes, due to its passive nature. A great deal of effort has been dedicated to improve the performance of the traditional base isolation system for these two types of earthquakes. Controllable supplementary and energy-dissipation members, such as magnetorheological damper, friction damper or hydraulic fluid damper, have been proposed to reduce the seismic response of the building structures. However, with the introduction of additional control devices, the system complexity increases which results in difficulty in the system implementation and control system design. It would be ideal if a certain level of adaptability could be introduced into the base isolator while maintaining the traditional outfit. This paper addresses the challenge facing the current base isolation practice and proposes a novel adaptive base isolator as solution to the problem. A smart rubber, namely, magnetorheological elastomer (MRE), is utilised in this research for its magnetic field-sensitive material property as the main element in the novel device. The tradition base isolation design for a large-scale structure with laminated steel and MRE layers is adopted. To verify and characterise the performance of the MRE base isolator, experimental testing was conducted on UTS shake table facility. Experimental results show that after being energised with magnetic field, the maximum force and the stiffness of the novel device can increase by up to approximately 45% and 37%, respectively. With the field-dependent stiffness and damping, the proposed adaptive base isolator is very promising in meeting the challenges associated with the base isolation encountered in practice. of the building structures. Yang (Yang, Danielians and Liu, 1991) presented a hybrid control system in which a passive or active mass damper, connected with base isolation system, is used to alleviate the deformation of seismic isolators. Although numerical results showed that the proposed system worked effectively, the hybrid system is less practical since it is difficult to implement a mass damper, either passive or active, on the seismic isolators. Destructive potential of near-source earthquakes to flexible structures still remains a challenge and has received considerable attention within the earthquake engineering community. Another effort to augment the adaptability of base isolation system has been to combine passive isolators with semi-active or active actuators to develop hybrid base isolation systems. Spencer (Ramallo, Johnson and Spencer, 2002) proposed a smart base isolation system, composed of conventional low-damping elastomeric isolators and smart controllable dampers, such as MR damper, to protect structures against extreme earthquakes. Wongprasert (Wongprasert and Symans, 2005) experimentally evaluated a smart base isolation system consisting of spherical sliding bearings and variable fluid dampers for a multi-storey building frame. In the above-mentioned research, the proposed base isolation systems proved to be more effective than the traditional passive ones. However, those systems, termed hybrid systems, are either a combination of passive bearings/isolators (such as low-damping bearing or spherical sliding bearings) and semiactive actuators (MR damper or piezoelectric friction damper) or a mixture of passive bearings/isolators and active actuating system. The separated passive and semi-active/active actuator increases the complexity of the base isolation system, leading to many problems, such as instability, reliability, and the increasing difficulty in system installation. Moreover, the need for large power in active hybrid base isolation systems restricts their implementation in largescale structures. The advent of a kind of smart material, magnetorheological elastomer, offers a way forward to develop more effective and efficient semi-active base isolators than traditional passive ones, and will further lead to the development of intelligent selfadaptive base isolation systems. Magnetorheological elastomer (MRE) is a new generation of MR materials whose stiffness and damping can be changed by magnetic field in real-time. In the absence of magnetic field, MRE is similar to that of a soft rubber. While under magnetic field, MRE turns to be very stiff. The maximum relative change of the modulus of the MRE can be from about 50% (stiffer rubber carrier) to beyond 300% (soft rubber carrier, such as silicone gel) (Davis, 1999). Damping ratio of the MRE can differ from 10% to 32% depending on the types of rubber matrix and iron particles, and is more affected by the magnetic field when the MRE is driven at a lower frequency (Chen, Gong and Li, 2008). Other merits of MREs are their low power requirement and rapid response to the magnetic field. Normally, magnetic coils will be designed and utilised to supply the currents for the energisation and control of the MREs. The power supply needed by the magnetic coil is only 20-40 volts which can be easily achieved by normal batteries and accumulators. MREs also have rapid response to magnetic fields and the time of response is less than 10 ms (Li, Zhang, Du and Chen, 2006.). Although the research and development in MRE material has been emerging in recent years, research on MRE applications can rarely be found. Majority of research on new MRE devices are reported in mechanical engineering. Ginder (Ginder, Scholotter and Nichols, 2001) piloted a pioneer theoretical work that utilised MREs as variable-spring-rate elements to develop an adaptive tuned vibration absorber. Deng (Deng and Gong, 2008) developed an adaptive tuned vibration absorber. Experimental results indicated that its natural frequency can be tuned from 27.5Hz to 40Hz. In civil engineering, however, the idea of using MRE as the fundamental material to develop adaptive MRE seismic isolators is quite new and novel. Hwang (Hwang, Lim, and Lee, 2006) carried out a conceptual study on the application of MREs to base isolation system for building structures. Usman (Usman, et al, 2009) numerically evaluated the dynamic performance of a smart base isolation system employing MR elastomer, and the results show that the proposed system outperforms the conventional system in reducing the responses of the structures during seismic excitations. Despite the two publications addressing the potential of MRE based base isolation system, the critical question on how to incorporate MREs into the base isolation system is yet to be addressed. This paper aims to design and develop an adaptive base isolator using the new smart material, MR elastomer, for its controllable material properties, including shear modulus and damping. A novel MRE base isolator with similar laminated structure of passive rubber base isolator is prototyped with the aim to comply with the requirement in the base isolation practice. Experiments were designed and conducted to examine the adaptive performance of the MRE base isolator. 2 MR ELASTOMER AND THE ADAPTIVE BASE ISOLATOR

Magnetorheological (MR) fluid as a new smart material has done well in the vibration and impact control engineering fields because of its good electromechanical coupling characteristics, preferable dynamic performance and higher sensitivity. And success of MRF has been apparent in many engineering applied fields, such as semi-active suspension, civil engineering, etc. So far, little research has been done about MR damper applied into the weapon system. Its primary purpose of this study is to identify its dynamic performance and controability of the artillery recoil mechanism equipped with MR damper. Firstly, based on the traditional artillery recoil mechanism, a recoil dynamic model is developed in order to obtain an ideal rule between recoil force and its stroke. Then, its effects of recoil resistance on the stability and firing accuracy of artillery are explored. Because MR gun recoil damper under high impact load shows a typical nonlinear character and there exists a shear-thinning phenomenon, to establish an accurate dynamic model has been a seeking aim of its design and application for MR damper under high impact load. Secondly, in this paper, considering its actual bearing load, an inertia factor was introduced to Herschel-Bulkley model, and some factor's effect on damping force are simulated and analyzed by using numerical simulation, including its dynamic performance under different flow coefficients and input currents. Finally, both of tests with the fixed current and different On-Off control algorithms have been done to confirm its controability of MR gun recoil damper under high impact load. Experimental results show its dynamic performances of the large-scale single-ended MR gun recoil damper can be changed by altering the applied currents and it has a good controllability.

The primary purpose of this study is to provide a comprehensive understanding on the controllability of a large-scale single-ended Magnetorheological (MR) shock absorber under impact load. Performances of MR shock absorber under random load, mainly in the transportation applications, seismic protection in civil engineering and wind-rain-induced load in Cable Bridge, are well investigated by many researchers. However, little research has been focused on the dynamic performance of MR shock absorber under impact load. Furthermore, the controllability of large-scale MR shock absorber under impact load is not researched in detail. In this paper, a test rig which uses a closed bump to produce an impact load is developed. A novel large-scale single-ended MR shock absorber without the accumulator is used as the specimen. To evaluate the controllability of MR shock absorber under impact load, several different currents are applied to the MR shock absorber. Moreover, an on-off control strategy is applied to the electromagnetic coil to investigate the dynamics of this shock absorber under impact load. It is indicated that this large-scale single-ended MR shock absorber has a good controllability compared with small double-ended MR shock absorber.Copyright © 2007 by ASME

This paper presents multi-physics modeling of an MR absorber considering the magnetic hysteresis to capture the nonlinear relationship between the applied current and the generated force under impact loading. The magnetic field, temperature field, and fluid dynamics are represented by the Maxwell equations, conjugate heat transfer equations, and Navier–Stokes equations. These fields are coupled through the apparent viscosity and the magnetic force, both of which in turn depend on the magnetic flux density and the temperature. Based on a parametric study, an inverse Jiles–Atherton hysteresis model is used and implemented for the magnetic field simulation. The temperature rise of the MR fluid in the annular gap caused by core loss (i.e. eddy current loss and hysteresis loss) and fluid motion is computed to investigate the current–force behavior. A group of impulsive tests was performed for the manufactured MR absorber with step exciting currents. The numerical and experimental results showed good agreement, which validates the effectiveness of the proposed multi-physics FEA model.

An efficient adaptive filtering algorithm for network echo cancellers is proposed in this paper. Employing the primary and auxiliary filter that operate parallel, an algorithm recently proposed named stochastic taps NLMS (ST-NLMS) estimates and locates the active region of the unknown system impulse response, therefore results a rapid transient behavior while estimating long, sparse, echo path like system. However, ST-NLMS still fails to give satisfactory estimation of effective system response region, hence leads to prohibitive computational complexity and further enhance potential. In this paper, based on the analysis to ST-NLMS, a new algorithm named ST-NLMS++ is proposed, which originally adopts hybrid active taps re-initialization and fake active tap elimination to enhance the estimation of active tap region. In stationary environment and small step-size assumption, theoretical examination reveals that ST-NLMS++ leads a superior estimation of effective impulse location and achieves faster tap-weight convergence as well as the same level of misadjustment compared to ST-NLMS and traditional NLMS. Experiments further verify the analysis and demonstrate that the tracking performance of proposed algorithm is also satisfying in both stationary and non-stationary scenarios

General dynamic analysis for fluid flow in microchannel was presented. A microfluid flow measuring system is set up for experimental study, then the microfluid flow behaviour in microchannel with different cross sections and characteristic size is investigated under the pressure difference ranged from 0-200Kpa. The Silicon nozzle/diffuser elements are fabricated and the flow directing property of them is investigated under 0-10 Kpa . The experiment results agree well with the expected.

Inspired by its controllable and field-dependent stiffness/damping properties, there has been increasing research and development of magnetorheological elastomer (MRE) for mitigation of unwanted structural or machinery vibrations using MRE isolators or absorbers. Recently, a breakthrough pilot research on the development of a highly innovative prototype adaptive MRE base isolator, with the ability for real-time adaptive control of base isolated structures against various types of earthquakes including near- or far-fault earthquakes, has been reported by the authors. As a further effort to improve the proposed MRE adaptive base isolator and to address some of the shortcomings and challenges, this paper presents systematic investigations on the development of a new highly adjustable MRE base isolator, including experimental testing and characterization of the new isolator. A soft MR elastomer has been designed, fabricated and incorporated in the laminated structure of the new MRE base isolator, which aims to obtain a highly adjustable shear modulus under a medium level of magnetic field. Comprehensive static and dynamic testing was conducted on this new adaptive MRE base isolator to examine its characteristics and evaluate its performance. The experimental results show that this new MRE base isolator can remarkably change the lateral stiffness of the isolator up to 1630% under a medium level of magnetic field. Such highly adjustable MRE base isolator makes the design and implementation of truly real-time adaptive (e.g. semi-active or smart passive) seismic isolation systems become feasible. © 2013 IOP Publishing Ltd.

Superconductivity has been found in newly discovered iron-based compounds. This paper studies the motion of magnetic vortices in BaFe1.9Ni0.1As2 single crystal by means of the magneto-optical imaging technique. A series of magneto-optical images reflecting magnetic flux distribution at the crystal surface were taken when the crystal was zero-field cooled to 10 K. The behavior of the vortices, including penetration into and expulsion from the single crystal with increasing and decreasing external fields, respectively, is discussed. The motion behavior is similar to that observed in high-Tc superconducting cuprates with strong vortex pinning; however, the flux-front is irregular due to randomly distributed defects in the crystal.

Magnetorheological fluid (MRF) has received significant attention lately and MRF based devices have been proposed for structural control applications in recent years. The unique characteristics of MR fluid lies in its abilities to reversibly, repeatedly and instantly change from a free flowing liquid to a semi-solid state when exposed to a magnetic field. The electric power required to drive the MR devices can be easily provided by a battery. Possessing such unique properties, MR fluid based devices, such as MR damper, have become promising candidates in the semi-active control for civil structure applications. However, most of the published research has focused on application of MR dampers instead of exploring other type of MR devices. In addition, MR based devices exhibit complex nonlinear hysteresis behaviour and thus making their modelling a challenging task. In this paper, a novel MR fluid based device, namely MR pin joint, is proposed as a smart structural member in development of an intelligent civil structure that can suppress unwanted vibrations to ensure safety and serviceability of the structure. After design and fabrication, experiments have been conducted to characterise dynamic behaviours of the new device under different harmonic excitations with various input currents. Response time of the MR pin joint is compared when the MR pin joint is driven under different applied currents and moving speeds. Test data shows that the MR pin joint possesses a unique behaviour in the moment-angular velocity plot. A hyperbolic hysteresis model is proposed to model such unique behaviour. The investigation presented in the paper explores dynamic performance of MR pin joint. Finally, a parametric model is developed following the investigation on the correlation of coefficients in the proposed model with the loading conditions and applied currents.