No abstract

In the current paper, the sensitivity performance of functionally graded magneto-electro-elastic (FG-MEE) nanoplate with attached nanoparticles as a nanosensor is analyzed based on nonlocal Mindlin plate assumption. Power law distribution model is employed to display how the material properties of FG-MEE nanoplate vary across the thickness direction. It is supposed that FG-MEE nanoplate is under initial external electric and magnetic potentials. Boundary condition of each edge of FG-MEE nanoplate is assumed to be simply supported. Furthermore, a Pasternak substrate is applied for modelling the total reaction pressure between nanoplate and foundation. Partial differential equations and corresponding boundary conditions are first achieved using Hamilton's variational principle and then analytically solved to determine the frequency shift utilizing Navier's approach. Numerical examples are performed to elucidate the dependency of the sensitivity performance of FG-MEE nanosensor on the volume fraction exponent, nonlocal parameter, total attached mass and location of the nanoparticle, aspect ratio, mode number, initial external electric voltage, initial external magnetic potential, and Pasternak medium coefficients. It is clearly indicated that these factors have highly significant impacts on the variations of frequency shift.

Elastomeric seals are prone to failure caused by abrasion during sliding against rough surfaces. In this research, the two-body abrasive wear of some selected sealing elastomers (nitrile rubber, hydrogenated nitrile rubber, acrylic rubber, and fluoro rubber) in dry and lubricated conditions has been studied. The influence of three different oils (synthetic ester, polyalphaolefin, and mineral oil) on the abrasive wear of the elastomers, at varying normal load and abrasive particle size, has been studied. The results show that, depending on the material, lubricant, abrasive size, and normal load, the abrasive wear of elastomers may increase or decrease in the presence of lubricants, and in most cases, the abrasive wear in the lubricated condition is higher than that in the dry condition. The influence of lubricant on the increase in abrasive wear is more significant during sliding against fine abrasives. Apart from the acrylic rubber, increase in the abrasive wear in presence of the synthetic ester is higher than those in presence of the mineral oil and polyalphaolefin.

Friction testing of elastomers in lubricated contact is discussed with a focus on developing experimental arrangements that can produce worthwhile results. Practical issues unique to elastomers are covered as well as their solutions, including contact mechanics, material response to loading, contact edges, oil absorption, cleaning and specimen geometry. A critique of reciprocating laboratory testing machines, including high-frequency short stroke and low-frequency long stroke friction and wear machines, is conducted for their usefulness, as is critical analysis of a wide variety of specimen confi gurations with the aim of helping the laboratory experimenter to overcome many of the pitfalls associated with testing of elastomers in lubricated conditions. Results from experiments using various testing arrangements are analysed, and it is found that the synthetic ester and mineral oil used produced similar results.