Vibration of a Two-Layer“Metal+PZT”Plate Contacting with Viscous Fluid

The present work investigates the mechanically forced vibration of the hydro-elasto-piezoelectric system consisting of a two-layer plate“elastic+PZT”,a compressible viscous fluid,and a rigid wall.It is assumed that the PZT(piezoelectric)layer of the plate is in contact with the fluid and time-harmonic linear forces act on the free surface of the elastic-metallic layer.This study is valuable because it considers for the first time the mechanical vibration of the metal+piezoelectric bilayer plate in contact with a fluid.It is also the first time that the influence of the volumetric concentration of the constituents on the vibration of the hydro-elasto-piezoelectric system is studied.Another value of the present work is the use of the exact equations and relations of elasto-electrodynamics for elastic and piezoelectric materials to describe the motion of the plate layers within the framework of the piecewise homogeneous body model and the use of the linearized Navier-Stokes equations to describe the flow of the compressible viscous fluid.The plane-strain state in the plate and the plane flow in the fluid take place.For the solution of the corresponding boundary-value problem,the Fourier transform is used with respect to the spatial coordinate on the axis along the laying direction of the plate.The analytical expressions of the Fourier transform of all the sought values of each component of the system are determined.The origins of the searched values are determined numerically,after which numerical results on the stress on the fluid and plate interface planes are presented and discussed.These results are obtained for the case where PZT-2 is chosen as the piezoelectric material,steel and aluminum as the elastic metal materials,and Glycerin as the fluid.Analysis of these results allows conclusions to be drawn about the character of the problem parameters on the frequency response of the interfacial stress.In particular,it was found that after a certain value of the vibration frequency,the presence of the metal layer in the two-layer plate led to an increase in the absolute values of the above interfacial stress.

Viscosity and Diffusion Effects at the Boundary Surface of Viscous Fluid and Thermoelastic Diffusive Solid Medium

This paper concentrates on the wave motion at the interface of viscous compressible fluid half-space and homogeneous isotropic,generalized thermoelastic diffusive half-space.The wave solutions in both the fluid and thermoelastic diffusive half-spaces have been investigated;and the complex dispersion equation of leaky Rayleigh wave motion have been derived.The phase velocity and attenuation coefficient of leaky Rayleigh waves have been computed from the complex dispersion equation by using the Muller’s method.The amplitudes of displacements,temperature change and concentration have been obtained.The effects of viscosity and diffusion on phase velocity and attenuation coefficient of leaky Rayleigh waves motion for different theories of thermoelastic diffusion have been depicted graphically.The magnitude of heat and mass diffusion flux vectors for different theories of thermoelastic diffusion have also been computed and represented graphically.

Numerical simulation of a complex moving rigid body under the impingement of a shock wave in 3D

In this paper,we take a numerical simulation of a complex moving rigid body under the impingement of a shock wave in three-dimensional space.Both compressible inviscid fluid and viscous fluid are considered with suitable boundary conditions.We develop a high order numerical boundary treatment for the complex moving geometries based on finite difference methods on fixed Cartesian meshes.The method is an extension of the inverse Lax-Wendroff(ILW)procedure in our works(Cheng et al.,Appl Math Mech(Engl Ed)42:841-854,2021;Liu et al.)for 2D problems.Different from the 2D case,the local coordinate rotation in 3D required in the ILW procedure is not unique.We give a theoretical analysis to show that the boundary treatment is independent of the choice of the rotation,ensuring the method is feasible and valid.Both translation and rotation of the body are taken into account in this paper.In particular,we reformulate the material derivative for inviscid fluid on the moving boundary with no-penetration condition,which plays a key role in the proposed algorithm.Numerical simulations on the cylinder and sphere are given,demonstrating the good performance of our numerical boundary treatments.

Effect of gas blowing on the head of thermal ablation vehicle

The reentry vehicle will encounter thermal ablation,especially at the stagnation point regime.A theoretical work has been done to analyze the thermal effect of gas blowing due to thermal ablation of surface material on the head of a general hypersonic vehicle.By deriving the formulation,research takes into account the effect of gas blowing on the thermal dynamics balance,and then solves them by numerical discretization.It is found that gas blowing will increase the temperature and heat flux at the surface of stagnation point regime.