نوع مقاله : مقاله علمی
عنوان مقاله English
نویسندگان English
Piezoelectric microcantilevers are important energy conversion elements in microelectromechanical systems for applications such as biosensors, energy harvesting, and underwater acoustic detection. In this study, the vibration behavior of a three-layer composite microcantilever with dimensions of 6 × 125 × 500 μm, consisting of a PZT-5H piezoelectric layer, a graphene-reinforced acoustic core with negative Poisson's ratio, and an aluminum base layer, is investigated. Free vibration analysis is performed using Timoshenko beam theory and the generalized difference-of-squares method, and the effect of fluid-structure interaction is considered through an added mass model and viscous damping. The analytical results are validated by 3D simulation in COMSOL Multiphysics software and show an error of less than 0.74% for the first seven modes. The results show that the use of an austenitic-graphene core with νa = −0.30 results in a 1.85% increase in the first mode frequency and a 34% improvement in shear stiffness compared to conventional cores, while the frequency ratio in water to air remains almost constant at 0.910. Modal energy analysis shows that the PZT layer absorbs about 52.8% of the bending energy and nearly 90% of the viscous dissipation occurs in the last 2.6% of the beam length. Also, sensitivity analysis shows that placing the microcantilever close to the free surface increases the frequency by about 0.6 to 1.5%, and proximity to the rigid bottom reduces it by about 1 to 3%, and this effect is intensified by increasing the density and viscosity of the fluid.
کلیدواژهها English
علم و فناوری در مهندسی مکانیک