Search

The paper develops a computation method for energy dissipation parameters in thin viscoelastic composite plates under steady vibrations. The method is based on applying the asymptotic theory of laminated thin plates, which allows us to calculate accurately enough all six components of the stress tensor under cyclic loading and also complete expressions for the energy dissipation function and the accumulated energy with account of transverse and interlayer shear stresses. With the help of the developed method, we simulate stresses and energy dissipation parameters in a viscoelastic plate of fiber laminated carbon–plastic composite under flexural vibrations. Computations showed that transverse stresses and especially interlayer shear stresses contribute considerably to the integral energy dissipation coefficient of composite plates. This contribution is the most significant for rigid structures with a relatively small energy dissipation coefficient. [ABSTRACT FROM AUTHOR]

In this paper, the asymptotic homogenization method is applied to the filtration theory of a generalized Newtonian fluid in periodic porous media. The asymptotic expansion of non-Newtonian viscosity is obtained by the asymptotic expansion of the second invariant of the strain tensor. The so-called local problem in periodic cells is presented to describe the microscale transport of a generalized Newtonian fluid in porous media. Based on nonlinear tensor function theory, the filtration law of generalized Newtonian fluid is obtained, which is used to describe the average process of filtration. A new numerical method to solve the local problem is proposed by using the least squares finite element method, and the permeability coefficient and effective viscosity of a generalized Newtonian fluid in porous media are evaluated. The exact solution of Poiseuille's flow in the microtube for a power-law fluid is obtained by theoretical analysis to verify the accuracy of the proposed model. Finally, the local transports of a shear-thinning Modified Cross fluid in two classical 2D porous structures are simulated and the dependencies of the permeability tensor and effective viscosity on the pressure gradient in porous structures are analyzed, which validates the proposed models and numerical methods. • A local problem on periodic cells is presented for the flow of a generalized Newtonian fluid in a single pore. • Developed the least squares finite element method to solve local problems. • The filtration law of a generalized Newtonian fluid is proposed using nonlinear tensor function theory. • Exact solutions for Poiseuille's flow of a power-law fluid in microtubes are obtained. • Local problems are solved and the permeability and effective viscosity in 2D porous structures are obtained. [ABSTRACT FROM AUTHOR]

Abstract: The present paper continues investigations devoted to the application of the homogenization method to transport theory in porous media. The method of solving so-called local problems of gas dynamics over a periodic cell has been developed there. Solution of the problems allows us to find accurate local distributions of velocities and pressures inside a separate pore, and also to evaluate the gas-permeability coefficient when only the geometric shape of pores is known. Computed results are shown and compared with experimental data. [Copyright &y& Elsevier]