Les polymères à mémoire de forme (SMP) sont des matériaux qui peuvent revenir à leur forme d'origine lorsqu'un stimulus approprié (par exemple de la chaleur) est prévu. Ces polymères sont programmés par cycle de mémoire de forme qui se compose de deux parties: une partie de la programmation qui donne un effet mémoire de forme (SME) à savoir la forme temporaire pour le polymère et la partie de récupération où il revient à sa forme initiale. Les SMP ont une faible rigidité, donc, produisent de grandes déformations récupérables, mais produisent des forces de récupération faibles. Cependant, les composites SMP produisent des forces de récupération plus grandes car ils sont relativement rigide mais ont des souches moins récupérables. En outre, de forts actionneurs à mémoire de forme peuvent être produits si deux effets différents peuvent être combinés dans une structure unique. Une structure déjà active (par exemple des alliages à mémoire de forme) peut être intégré dans SMP. Par conséquent, un fort actionneur couplé peut être obtenu. [...] / Shape memory polymers (SMPs) are the materials which can return to their original shape when a suitable stimulus (e.g. heat) is provided. These polymers are programmed through shape memory cycle that consists of two parts: programming part which gives shape memory effect (SME) i.e. temporary shape to the polymer and the recovery part which return it to its original shape. SMPs have low stiffness, therefore, produce large recoverable strains, but produce low recovery forces. However, SMP composites produce larger recovery forces as they are relatively rigid but have less recoverable strains. Moreover, strong shape memory actuators can be produced if two different effects can be combined in a single structure. An already active structure (e.g shape memory alloys) can be embedded in SMP. Consequently, a strong coupled actuator can be obtained. In this work, the shape memory property of CBCM composite (an active composite that works on bimetallic affect) has been studied. CBCM stands for controlled behavior of composite material. CBCM activeness and its SM property has been coupled together to obtain a strong actuator. SM property has been obtained through thermo-mechanical programming at a temperature higher than glass transition temperature (Tg) of Epoxy resin used for its fabrication. The CBCM actuating properties have been studied through different one-step recoveries (unconstrained, constrained and recovery under load). Moreover, different asymmetrical CBCM composites have been developed by changing the position and orientation of the different layers used. These have been studied for their different actuation properties. Similarly, multi-step recoveries (unconstrained and constrained) have also been performed to show multi step actuation capabilities in CBCM. The actuating properties of CBCM have also been compared with symmetrical composite (SYM) to show the advantage of coupled properties in CBCM. It has been found that CBCM has the ability to give high strain, high recovery forces. Also, it can recover under load and recover to its original position at the temperatures lower than the deforming temperature used in the programming cycle.
| Identifer | oai:union.ndltd.org:theses.fr/2012MULH8494 |
| Date | 18 December 2012 |
| Creators | Basit, Abdul |
| Contributors | Mulhouse, Durand, Bernard |
| Source Sets | Dépôt national des thèses électroniques françaises |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation, Text |
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