The design and implementation of linear nonlinear control methods for a three-pole active magnetic bearing (AMB) is presented in this paper. It shown that the system has nearly dynamics by adding bias to coil currents. A decentralized PID feedback law an integral sliding mode controller are proposed unknown state variables estimated Kalman filter. optimal gains determined LQG technique. To evaluate effectiveness controllers, they implemented on experimental setup. results show can...

This paper presents the potential of acoustic emission (AE) technique to detect valve damage in internal combustion engines. The cylinder head a spark-ignited engine was used as experimental setup. effect three types (clearance, semicrack, and notch) on leakage investigated. results showed that AE is an effective method type valves both time frequency domains. An artificial neural network trained based domain analysis using parametric features (<mml:math...

In this study, the hydrodynamics and noise behaviour of marine propellers are examined through finite volume method under various operational conditions. The these studied both numerically experimentally, characteristic curves produced. Sheet cavitation inception development conditions also considered in order to understand impact different rotational speeds on propeller noise. Ffowcs Williams Hawkings equations used extract total sound pressure levels non-cavitating sheet cavitating...

This study is concerned with the problem of harmonic disturbance rejection in active magnetic bearing systems. A modified notch filter presented to identify both constant and disturbances caused by sensor runout mass unbalance. The proposed method can attenuate displacement currents at synchronous frequency its integer multiples. reduction stability a common adaptive techniques because they alter original closed-loop system. main advantage that it possible determine margins system few...

This paper considers optimal synthesis of a special type four-bar linkages. Combination this linkage with on it's cognates and elimination two redundant will result in Watt's six-bar mechanism, which generates straight parallel motion. mechanism can be utilized for legged machines. The advantage is that the leg remains during contact period because motion, legs as wide desired to increase area decrease number required keep body's stability statically dynamically. “Genetic algorithm”...

In this article, wave endurance time (WET) is addressed as an applicable method for performance-based assessment of fixed offshore structures under extreme waves. method, inspired by the in field earthquake engineering, artificial records called functions are designed so that their excitations gradually increase with time. Therefore, main advantage proposed it can assess structural performance various load conditions through a single time-history analysis. Moreover, reliability be evaluated...

The main objective of this investigation is to modify endurance wave analysis (EWA) based on New-wave theory for convenient assessment offshore structures under extreme waves. EWA a novel time history approach evaluate structural performance in various excitation levels loading by intensifying records. In article, modifications are proposed determine appropriate duration and trend reliable practical structures. way, simplified model real jacket platform utilised investigate the application...

The wave endurance time method is a novel dynamic approach to conveniently estimate structural performance under various extreme conditions. In this method, offshore structures are subjected gradually intensifying sea surface profile called function, and their assessed in different state conditions by single history analysis. From analysis perspective, behavior judged based on the maximum duration that structure can withstand function. study, description of concept presented, generation...

Asymmetrical planing catamarans are increasingly used in moderate to very high-speed applications due some tempting qualities such as less wetted surface and better seakeeping behavior. The present numerical study attempts provide new insight into hydrodynamics of vessels by highlighting the distinguishing aspects employing novel appropriate approaches deal with them. A systematic investigation has been carried out on a prismatic geometry at various demihull separations (including zero...

The aim of this paper is to consider the ability endurance time (ET) method estimate seismic response fixed offshore platforms at various excitation levels. In way, sources nonlinear behaviour and challenging issues in ET approach are included three-dimensional model a real jacket platform utilising finite element method. addition common-designed, over-designed under-designed cases have been investigated examine effects structural characteristics on response. To accuracy reliability...

Properly adjusting the trim angle during craft speed up will be extremely important in special cases as sports competitions or military missions. In such applications, goal of adjustment is to reach final a minimum possible time which an advantage just passing resistance hump. Present study tries provide insight into how angles drive system and tab planing should changed so minimise speed. This time-optimal control problem with variables. Optimal theory has been used previously for motion...

Finding leakage in valves is important to troubleshoot performance of internal combustion engines. Leakage can lead a reduction engine power and an increase emissions. The main objective the present study investigate relationship between valve acoustic emission generated from steady flow cylinder head engine. test rig for spark-ignited simulates due clearance. clearance fault was artificially simulated by very small lift valve. method used measure signals flow. Characteristics time frequency...

Estimation of rolling bearing life with damage curve approach The ability to determine the time is one main purposes in maintenance rotating machineries. Because reliability, cost and productivity, prognostic important. In this paper, a stiffness-based model for systems discussed. According presumed fundamental mechanics, used relate stiffness vibratory system running life. Furthermore, using relation between acceleration amplitude at natural frequency stiffness, final according can be...

In this paper, cavitation inception and development conditions are studied for five-blade propellers by experiments carried out in tunnel. Propeller noise is measured different operating uncoated coated also, the effects of silicone foul release (FR) coating, inter sleek 700 (IS700), investigated on delay reduction a marine propeller Finally, results presented low advance coefficients development, reduction. These can be applied as reference validating model numerical simulations.

In the recent years, di erent mathematical models have been suggested for maneuvering of displacement vessels that are capable estimation vessel maneuvers with acceptable precision. These based on determined hydrodynamic coecients and their accuracy depends known used to solve model. System identi cation methods developed calculate these utilizing input output data obtained from sources. this research, a 4.36-m model KRISO Container Ship (KCS) has manufactured by berglass, maneuver turning...

In the recent years, different mathematical models are suggested for maneuvering of displacement vessels which capable to estimate vessel maneuver with acceptable precision. But simulation planing craft maneuverability through model is not developed yet. this paper a by including rudder forces and moments. Different maneuvers executed such as straight-line stability, course keeping turning circle maneuver. Simulation results were validated published experimental they in good agreement....

In this paper, the motion of a high speed vessel with planing hull has been investigated using experimental and numerical methods. The aim investigation was to compare results model towing test obtained in Savitsky method.The most important issue modeling is determine its continuous conditions, such as trim draught. Comparing results, it concluded that they are non-variant range spite uncertainties hence positions. Therefore, could be expected more complete modeling, study conditions becomes...