Optimisation du comportement électromécanique d’une mousse piézorésistive de polyuréthane en régime quasi-statique et dynamique - Archive ouverte HAL Accéder directement au contenu
Communication Dans Un Congrès Année : 2019

Optimisation du comportement électromécanique d’une mousse piézorésistive de polyuréthane en régime quasi-statique et dynamique

Jean-Christophe Walrick
Antoine Poirot
Nacera Bedrici
M. Arrigoni

Résumé

From transportation to space including defense applications, engineered systems are likely to face dynamic loads such as impact, drop or blast loadings. In order to assess the residual strength or the survivability of the target, is it necessary to bring models when experiments turn to be destructive and thus expansive. The modelling also meets some limits because it cannot be relevant regarding the too large variety of material behavior or loading. At such a point it is then important to implement Structural Health Monitoring (SHM) techniques in systems in service, especially able to monitor dynamic events. From this fact, implementation of physical sensors in structures are needed. The presented work aims at implementing a sensor within a structural assembly and then to observe its response to a dynamic loading. A first suggestion is the use of an electrically conductive foam. As a first step, it is necessary to know about its constitutive law and the relation between stress and conductivity. An open-cell foam with a low density (20 kg.m-3) coated with a conductive solution is thus studied. The work describes the elaboration of the sample and its electrical response when subjected to compression tests in order to assess its piezoresistive response. In that purpose, the foam is characterized with quasi-static tests (cyclic uniaxial compressions at low velocity) conducted with a press, in free and confined (oedometric) configurations. These tests are performed in the same humidity and temperature conditions. It is observed that the electrical response (sensibility, signal stability) of the conductive foam depends on its mechanical behavior which depends on its physical parameters. Thereby, the morphology (geometry, size and repartition of cells, density…) of the conductive foam and its electrical conductivity are key parameters to be considered in the characterization. To optimize the deformation and pressure sensibility of the foam, it is coated with a conductive ink based on PEDOT:PSS copolymers at various concentration ratios. Finally, a calibration of studied samples could be achieved in quasi static regime and its dependency to key parameters was assessed. As a second step, the dynamic characterization of the foam is studied. The objective is to evaluate the performance of the foam as a shock sensor by identifying the key parameters. Initially, it consists of subjecting low energy impacts on a sandwich structure with integrated foam sample. From the results, the sensing performance depends on various parameters such as foam calibration, conductivity and sandwich constitution (materials, dimensions…). Supplementary tests could be performed with Hopkinson bars for obtaining high rate foam behavior and defining its pressure sensing range. The dynamic behavior of the conductive foam is compared to that in quasi static regime. The role played by viscoelasticity in the electrical response is then evidenced.
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Dates et versions

hal-04480042 , version 1 (27-02-2024)

Identifiants

  • HAL Id : hal-04480042 , version 1

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Jean-Christophe Walrick, Antoine Poirot, Nacera Bedrici, M. Arrigoni. Optimisation du comportement électromécanique d’une mousse piézorésistive de polyuréthane en régime quasi-statique et dynamique. 25ème Congrès Français de Mécanique, Aug 2019, Nantes, France. ⟨hal-04480042⟩

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