A New Moving Kirchhoff-Love Plate Element for Dynamic Analysis of Vehicle-Pavement Interaction

A new moving Kirchhoff-Love plate element is developed in this work to accurately and efficiently calculate the dynamic response of vehicle-pavement interaction. Since the vehicle can only affect a small region nearby, the wide pavement is reduced to a small reduced plate area around the vehicle. The vehicle loads moving along an arbitrary trajectory is considered, and the arbitrary Lagrangian-Eulerian method is used here for coordinate conversion. The reduced plate area is spatially discretized using the current moving plate element, where its governing equations are derived using Lagrange's equations. The moving plate element is validated by different plate subjected to moving load cases, where the influences of different factors on reduced plate area length of the RBM model are also investigated. Then a vehicle-pavement interaction case with constant and variable speed is analyzed here. The calculation results from the moving plate element are in good agreement with those from the modal superposition method (MSM), and the calculation time with the moving plate element is only one third of that using the MSM. It is also found that the moving load velocity and ground damping have great influences on reduced plate area length of the RBM. The moving plate element is accurate and more efficient than the MSM in calculating the dynamic response of the vehicle-pavement interaction.

Effect of Chemical Reaction towards MHD Marginal Layer Movement of Casson Nanofluid through Porous Media above a Moving Plate with an Adaptable Thickness

In the current workflow and heat exchange of a Casson nanoliquid across a penetrable media above a moving plate with variable thermal conductivity, adaptive thickness and chemical reaction are analyzed. First, the governing nonlinear equations of partial derivative terms with proper extreme conditions are changed into equations of ordinary derivative terms with suitable similarity conversions. Then the resulting equations are worked out using the Keller box method. The effects of various appropriate parameters are analyzed by constructing the visual representations of velocity, thermal, and fluid concentration. The velocity profile increased for shape parameter, and the opposite trend is observed for magnetic, Casson, porosity parameters. Temperature profile increases for magnetic, Casson, Brownian motion parameter, and thermophoresis parameters. Concentration profiles show a decreasing trend for wall thickness, Brownian movement, chemical reaction parameters. Also, skin friction values and calculated and matched with previous literature found in accordance. Also, local parameters Nusselt and Sherwood numbers are calculated and analyzed in detail.

Turbulent boundary layer heat transfer of CuO–water nanofluids on a continuously moving plate subject to convective boundary

The turbulent boundary layer (TBL) heat transfer of CuO–water nanofluids on a continuously moving plate subject to convective boundary are investigated. Five different shapes of nanoparticles are taken into account. Prandtl mixing length theory is adopted to divide the TBL into two parts, laminar sub-layer and turbulent region. The numerical solutions are obtained by bvp4c and accuracy is verified with previous results. It is found that the transfer of momentum and heat in the TBL is more obvious in laminar sub-layer than in turbulent region. The rise of velocity ratio parameter increases the velocity and temperature while decreases the local friction coefficient. The heat transfer increases significantly with the increase of velocity ratio parameter, Biot number, and nanoparticles volume fraction. For nanoparticles of different shapes, the heat transfer characteristics are Nu x (sphere) < Nu x (hexahedron) < Nu x (tetrahedron) < Nu x (column) < Nu x (lamina).

Inertial contributions to friction measurements in thrust bearings

Surface textures decrease friction in lubricated sliding contact. Traditionally, the friction reduction for a given textured surface is determined by using the Reynolds equation, which neglects fluid inertia. However, as the separation and relative motion between the surfaces increase, inertia can affect the measured tangential and normal forces for flow over a textured surface, and thus cause the coefficient of friction to differ from the purely viscous, Stokes flow prediction. Here, the increase in torque and normal force between a moving plate and stationary textured surface, which simulates a textured thrust bearing, are calculated as a function of the Reynolds number in the thin film limit. The predictions for a non-textured thrust bearing are compared to fully 3-D numerical simulations of the incompressible Navier-Stokes equation, and the predictions for textured thrust bearings are compared to experimental data given in the literature. Good agreement is seen between the predictions and the data, validating the predicted scaling laws. This work also suggests that inertia can be used as a secondary effect to reduce friction in lubricated sliding, and textures that take advantage of the inertial effects will have lower friction than textures that only use purely viscous effects.

Flow and Heat Transfer of MHD Dusty Nanofluid Toward Moving Plate with Convective Boundary Condition

This paper considers the flow and heat transfer characteristics of dusty nanofluid over a moving plate in the presence of magnetohydrodynamic (MHD) with convective boundary condition. Two types of nanofluid namely CuO-water and Al2O3-water permeated with dust particles are considered. The governing partial differential equations are converted into a system of non-linear ordinary differential equations using similarity transformation, then the non-linear ordinary differential equations are solved using shooting method with fourth-fifth order Runge-Kutta Fehlberg method (RKF45). The influence of non-dimensional governing parameters such as velocity ratio parameter, magnetic field parameter, volume fraction of the nanoparticle, volume fraction of the dust particle, mass concentration of the dust particle, fluid particle interaction parameter for velocity, fluid particle interaction parameter for temperature and Biot number on the velocity and temperature profiles for fluid and dust phases of CuO-water and Al2O3-water dusty nanofluids are discussed and presented through graphs. The skin friction coefficient and Nusselt number are discussed and presented in tabular form.

Electrical Power Generation Using Dynamic Piezoelectric Shear Deformation Under Friction

A new electrical power generation device based on high-frequency dynamic piezoelectric shear deformation under friction is developed. During the operation of a moving plate compressed and sliding on the top of a piezoelectric patch with constant velocity, dynamic shear deformation of the elastic piezoelectric patch is excited by periodic friction force and status (sliding and stick) variation. The dynamic piezoelectric shear strain can then generate continuous electrical power for energy absorbing and harvesting applications. The design of the piezoelectric couple device is first provided, and its mechanism, dynamic response and electric power generation under friction are described by a detailed iteration model. By comparing with previous experimental results, the accuracy of the proposed model is proven. Through numerical studies, the influences of the equivalent mass of the system, the velocity of the sliding object, the static friction coefficient and its lower limit, as well as the friction force delay rate on the power generation are obtained and discussed. The numerical results show that with the proposed design, up to 50-Watt maximum electrical power could be generated by a piezoelectric patch with a dimension of $$20\times 2\times 6$$ 20 × 2 × 6 cm under continuous friction with the moving plate at the velocity of 15 m/s. The possible bi-linear elastic stiffness variation of the system is also introduced, and the threshold of bi-linear elastic deformation, where the system stiffness changes, can be optimized for obtaining the highest power generation.