In the present research, vibrational behavior of anisotropic protein microtubules (MTs) immersed in cytosol via Cooper–Naghdi shell model is investigated. MTs are hollow cylindrical structures in the eukaryotic cytoskeleton which surrounded by filament network. The temperature effect on vibration frequency is also taken into account by assuming temperature-dependent material properties for MTs. To enhance the accuracy of results, strain gradient theory is utilized and the motion equations are derived based on Hamilton’s principle. Effects of various parameters such as environmental conditions by considering the surface traction of cytosol, length scale, thickness and aspect ratio on vibration characteristics of anisotropic MTs are studied. Results indicate that vibrational behavior of anisotropic MTs is strongly dependent on longitudinal Young’s modulus and length scale parameters. The results of this investigation can be utilized in the ultrasonic examine of MT organization in medical applications particularly in the treatment of cancers. تفاصيل المقالة

In this paper, thermal dynamic stability analysis of sandwich microbeams made of a honeycomb core and piezoelectric and porous visco graphene sheets resting on visco Pasternak is studied. The microbeam is modeled based on the zigzag theory and in order to incorporate the size effect, strain gradient theory is utilized. The set of the governing equations are derived Hamilton’s principle and are solved numerically using Galerkin method. The influences of various parameters on the thermal dynamic stability characteristics of the sandwich nanobeam are investigated including small scale, temperature changes, core to face sheets thickness ratio, intensity of electric fields and stiffness of elastic medium. The results of present work can be used to optimum design and control of micro-thermal/electro-mechanical devices. تفاصيل المقالة