In this study, the wave propagation properties of piezoelectric sandwich nanoplates deposited on an orthotropic viscoelastic foundation are analyzed by considering the surface effects (SEs). The nanoplates are composed of a composite layer reinforced by graphene and two piezoelectric surface layers. Utilizing the modified Halpin-Tsai model, the material parameters of composite layers are obtained. The displacement field is determined by the sinusoidal shear deformation theory (SSDT). The Euler-Lagrange equation is derived by employing Hamilton’s principle and the constitutive equations of piezoelectric layers considering the SEs. Subsequently, the nonlocal strain gradient theory (NSGT) is used to obtain the equations of motion. Next, the effects of scale parameters, graphene distribution, orthotropic viscoelastic foundation, and SEs on the propagation behavior are numerically examined. The results reveal that the wave frequency is a periodic function of the orthotropic angle. Furthermore, the wave frequency increases with the increase in the SEs.
We want in this note to clarify some aspects of the Machian foundation of the concept of mass in classical mechanics; specifically, we show how the relations of transitivity for the mass-ratios, necessary for a well grounded definition of mass, can be derived from Machian postulates. 相似文献
A scheme is developed for analysing the interaction between a foundation and a nonlinear rock and soil medium, in which the
foundation is considered as a linear elastic body and a typical boundary integral equation method (BIEM) is employed. On the
basis of taking the nonlinear properties of the medium into account, a perturbation BIEM is developed. The fundamental equations
for the nonlinear coupling analysis are formulated, and typical problems are solved and discussed by the present method. 相似文献
A monotone dependence of the critical buckling load of a simplysupported TimoshenkoMindlin beam both on the shear correctionfactor and on the stiffness of foundation is proved. Then theworst-scenario method is employed to find the most dangerousinput data. 相似文献
This paper presents the mathematical hypothesis that a beam on equidistant elastic supports (BOES) can be considered as a beam on an elastic foundation (BOEF) in static and free vibration problems. This modeling of BOES as BOEF is presumed to be applicable to a limited range of support stiffness, spacing and flexural rigidity of the beam. The authors investigate the applicability of the modeling of BOEF from the property of characteristic solutions obtained from governing equations of both BOES and BOEF. In this study, the formulation of BOES leads to governing difference equations, and the motions of BOEF are expressed by differential equations. This is because exact solutions must be employed in order to verify their analogy accurately. The characteristic solutions obtained from these two governing equations are compared to each other in order to investigate the relationship between them. 相似文献
Summary We have examined the effect of particle size of silica-based reversed-phase packings and column packing techniques on the
reversed-phase analytical separation of a peptide mixture. A C18 packing of 15–20 μm average particle size produced satisfactory peptide resolution, allowing a relatively inexpensive scale
up to the preparative purification of peptides. A shallow gradient (0.1% acetonitrile/min) elution procedure was developed
for the preparative purification of closely related decapeptides (differing by one methyl group) on analytical (250×4.1 mm
I.D.) and semipreparative (250×10 mm I.D.) columns. Up to 30 mg and 225 mg of the two-peptide mixture was efficiently resolved,
with high yields of homogeneous peptides, on analytical and semipreparative columns, respectively, containing the 15–20 μm
packing. We have also demonstrated the potential of our purification procedure for resolving more complex multicomponent mixtures
by efficiently separating a total of 22 mg of three closely-related peptides on analytical columns containing 7 μm or 15–20
μm particle size reversed-phase packings. The use of the inexpensive 15–20 μm packing, coupled with the ability to pack efficient
columns with analytical HPLC instrumentation, offers great cost saving potential. 相似文献