Context and motivation

This work is made under a cooperation through my thesis ( Actuation of Bistable Mechanisms) between the Institut Jean le Rond d'Alembert and the Sensory Interfaces Laboratory. It's cofunded by the CEA and the CNRS.

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The Institut Jean le Rond d'Alembert (formerly the "Laboratoire de Modelisation en Mecanique", with other labs) is an excellence Mechanics Laboratory, with specialists of several fields, including fluid mechanics, solid mechanics, cracks, vibration propagation, accoustics, mechanical stabilities and instabilities, numerical solving or applied mathematics. It is part of the Pierre and Marie Curie University, a.k.a. Paris 6.

Pr. Joël Pouget and Dr. Amancio Fernandes are specialists of modelisation of complex behavior in mechanics, including smart materials such as piezo systems, and their use in mechatronic devices. They also are expert in the field of non-linear behavior of structures, including things as the elastica, and mechanical branch bifurcations. For this point of view, bistable systems are a very interesting and real-world application of several non-linear theories.

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The Sensory Interfaces Laboratory is a component of the CEA List , a software systems and technology research center which helps transferring cutting-edge technologies to industry partners. The Sensory Interface Lab is specialised is haptic and sensory interfaces, that are human interfaces using the sense of touch to transmit informations. They are prototyping several kinds of interfaces from the mechanical design to the electronical parts.

Moustapha Hafez, PhD, is head of this lab, and a specialist of the use of smart materials for embedded systems, mainly sensory interfaces. He worked on bistable mechanisms during his Post-Doc at MIT, and see these systems as an excellent mechanical solution to reduce the power consumption of quasi-static devices actuated by smart materials.

The main point of this work is to explore designs for use of a system made of a bistable buckled beam and an actuator made of a smart materials. It includes a modelisation of a bistable beam with a force or torque actuation, localized or distributed, and considerations of severals smart materials (shape memory alloys, piezo actuators, electro-active polymers, IPMC's...). These actuators become very interesting at small sizes, when on the opposite the classic magnetical motors become very difficult to integrate and to fabricate.