Study on Dynamic Characteristics of Microchannel Fluid–Solid Coupling Systems in Nonlocal Stress Fields

Abstract

Objective of the present work is predicting the dynamic behaviors of fluid-filled microchannels when considering the small-scale effects caused by microchannel and inner fluid. A dynamic Euler–Bernoulli beam model for fluid-filled microchannels is established when applying the nonlocal strain gradient constitutive equation and nonlocal fluid shear stress equation. The scale effects of microtubes are simulated by nonlocality of elastic stress and gradient effect of strain when the fluid nonlocality is applied for predicting the scale effects induced by fluid flow. The dynamic equilibrium equations and boundary conditions for the dynamic tube are derived. By solving the equilibrium equations, different types of scale effects on wave propagation behavior are analyzed. The numerical results indicate that the nonlocal effect induced by microchannels dampens propagation for waves of short wavelengths, whereas the strain gradient effect enhances wave propagation at all wavelengths. The scale effect contributed by fluid flow also leads to decaying of the wave, because the flow velocity is reduced by the nonlocality of the fluid.