The objective of this paper is to mitigate the wave-induced vibration of offshore platform with magneto-rheological (MR) damper. The model of the platform coupled with MR damper is established where the external wave force is approximated with a white noise via a designed filter. Based on Linear Quadratic Gaussian (LQG) method, the optimal control force is determined when taking the measurement...

In this study, mass, stiffness and damping matrices of the Nosrat jacket; located in Persian Gulf; equipped with Semi Active Tuned Mass Damper (SATMD) system have been derived after modeling the structure in SACS software. Owing to huge number of the degrees of freedom in the model, computation of on-line control of SATMD was time consuming. For this purpose, the size of the model was reduced i...

A stochastic change detection methodology for reliable monitoring complex nonlinear dynamic systems is proposed. For a semi-active magneto-rheological (MR) damper, the non-parametric, data-driven restoring force method was used to identify the nonlinear dynamic damping device. Both supervised and unsupervised statistical pattern recognition techniques were used to detect the changes in the phys...

In the area of semi-active control of civil structures, Magneto-Rheological (MR) damper has been an efficient mechanism for reducing the seismic response of structures. In this paper, an effective method based on defining an optimization problem for designing MR dampers has been proposed. In the proposed method, the parameters of semi-active control system are determined so that the maximum res...

A comparative analysis of different models of a Magneto-Rheological (MR) damper was done. Three models were tested: a non-linear ARX, a semi-phenomenological and a phenomenological. Although the non-linear ARX model shown the best result, this is a black-box model with limited use. However, the Semi-Phenomenological model represented an excellent option considering the physical meaning of its p...

With the development of technology, new materials have been invented, which have been applied to improve the performance of structures. Recently, researchers pay their attention to controllable fluids and its applications. Magneto rheological (MR) damper is a kind of devices that uses rheological fluids to modify their mechanical properties. Their mechanical simplicity, large dynamic range, low...

An end milling process is widely used in fabrication of complex contours and shape parts at high spindle speeds. Many researchers try to investigate one of important aspect, which come across during machining is the self exited chatter vibration which causes severe damage of the tool and quality of the machined surface. The present work is focused on the Magneto-Rheological Damping effect on st...

Magneto-rheological (MR) fluid damper is a semiactive control device that has recently received more attention by the vibration control community. But inherent hysteretic and highly nonlinear dynamics of MR fluid damper is one of the challenging aspects to employ its unique characteristics. The combination of artificial neural network (ANN) and fuzzy logic system (FLS) have been used to imitate...

In this paper the performance of Artificial Neural Networks (ANNs) and Adaptive Neuro- Fuzzy Inference Systems (ANFIS) in simulating the inverse dynamic behavior of Magneto- Rheological (MR) dampers is investigated. MR dampers are one of the most applicable methods in semi active control of seismic response of structures. Various mathematical models are introduced to simulate the dynamic behavi...

Magneto-rheological dampers (MR-Dampers) are increasingly being used in construction applications to reduce the dynamic response of structures seismic activities or severe wind loading. Sensors attached structure will signal computer supply with an electric charge that transfers MR fluid a near-solid material different physical and mechanical properties (viscoelastic behavior). Control algorith...