Gas-lifted oil wells are susceptible to failure through malfunction of gas lift valves (GLV). One failure mode occurs when the GLV check valve fails and product passes into the well annulus, potentially reaching the wellhead. This is a growing concern as offshore wells are drilled thousands of meters below the ocean floor in extreme temperature and pressure conditions and repair and monitoring ...

The thermomechanical performance of a shape memory alloy hybrid composite beam specimen is demonstrated and used in a preliminary validation study of a recently developed constitutive model and finite element formulation for analysis of such structures. A brief description of the thermoelastic formulation is given. A material system consisting of a glass/epoxy matrix with embedded Nitinol actua...

This paper presents the ideology of this research, which is to utilize advanced actuators to design and develop innovative, lightweight, powerful, compact, and dexterous robotic technology. The key to satisfying these objectives is the use of advanced or smart materials, such as Shape Memory Alloys (SMAs) to power the joints of a prosthetic hand, and other dexterous robotic hands. The mechanica...

In order to exhaustively exploit the high-level capabilities of shape memory alloys (SMAs), they must be applied in control systems applications. However, because of their hysteretic inherent, dilatory response, and nonlinear behavior, scientists are thwarted in their attempt to design controllers for actuators of such kind.  The current study aims at developing a micro-position control system ...

A novel Shape Memory Alloy (SMA) actuator consisting of a number of thin NiTi bers woven in a counter rotating helical pattern around supporting disks is rst described. This structure can be viewed as a parallel mechanism used to accomplish a highly ee-cient transformation between force and displacement. The actuator overcomes the main mechanical drawback of shape memory alloys, that being limi...

 A variety of microrobots have commonly been used in the fields of biomedical engineering and underwater operations during the last few years. Thanks to their compact structure, low driving power, and simple control systems, microrobots can complete a variety of underwater tasks, even in limited spaces. To accomplish our objectives, we previously designed several bio-inspired underwater microro...

Résumé. Le principe d’un ordonnancement coopératif selon une modélisation multi-agents résulte du rapprochement des domaines de l’Ordonnancement et de l’Intelligence Artificielle Distribuée. Le travail que nous présentons dans ce papier a pour objectif l’étude de l’adéquation des métaheuristiques avancées dans un SMA dans le cadre de la résolution d’un problème d’optimisation bien défini qui es...

In recent years, considerable underwater robotics research has focused on manipulating sophisticated systems for inspecting and maintaining underwater structures, which can include cluttered and complex areas such as narrow clear spaces. These robots may be used for feature and cable tracking, deep-ocean exploration, and to carry out tasks in environments full of coral reefs (Zhang et al. 2004;...

in this paper the active vibration control of a four-story shear frame instrumented with piezoelectric actuators is presented. the piezoelectric actuators are hosted on the columns in two manners and the produced controlling forces by actuators are considered in the equation of motion. the smart structure modeling and control design is carried out using matlab software in state space form. subs...