A hybrid phenomenological model for thermo-mechano-electrical creep of 1–3 piezocomposites

ABSTRACT

Piezocomposites find extensive use in sensors and actuators, naval applications, etc. owing to their characteristic coupling between electro-mechanical domains. These materials being relatively soft and ductile show a viscoelastic response to applied thermo-mechano-electrical loads. This causes a drift in the system response and creep is observed, which affects system efficiency. During prolonged service periods, self-heating occurs. Often, piezocomposites are subjected to mechanical pre-stresses prior to electrical input. To understand the response of 1–3 piezocomposites under these intricate loading conditions, experiments are performed to study the electro-mechanical response of 1–3 piezocomposites under thermo-mechano-electrical creep loads. Mechanical depolarisation is observed during the creep process. Creep strain is observed to increase with matrix volume fraction, mechanical pre-stress, electric field and temperature. A decrement in creep polarisation is seen with the increase in matrix volume fraction, mechanical pre-stress and temperature. The system performance is observed to be strongly dependent on the fibre volume fraction. A hybrid model is proposed within a thermodynamic framework to predict the creep response of 1–3 piezocomposites under thermo-mechano-electrical loads. The model is simultaneously representative of the macroscopic phenomenological details and mesoscopic electro-mechanical insights. While the free energy potential and domain switching concepts are characteristic of macroscopic modelling, the representative volume element (RVE) and its description with regard to domain wall resistance can be related to the mesoscopic length scales. The model predictions are found to be in agreement with the experimental observations.

KEYWORDS:

• Viscoelastic
• thermo-mechano-electrical creep
• mechanical depolarisation
• hybrid model
• RVE
• thermodynamic framework

Disclosure statement

The authors declare no potential conflict of interest.

Additional information

Funding

The authors would like to acknowledge the financial support by the Naval Research Board [Project No.: NRB-379/MAT-16-17].