Normal Force Stress Research Articles

Computational fluid dynamics predictions of critical hydrodynamics thresholds in the erodibility of inland waterway bank by ship-induced waves

A three-dimensional numerical simulation method based on the resolution of Navier–Stokes equations is used to determine the causal relationship between the ship-induced waves and the erosion phenomenon of the inland waterway banks, and also to provide the critical conditions for waterway bank protection. The erosion process of the bank is defined here as the criterion in which the movements of the discrete medium blocks and particles that form the banks by the action of ship waves undergo a significant jump beyond the critical value of Froude number (Frc). By investigating the wave elevation drawdowns nearby the waterway banks, it is shown that the normal impact force and tangential shear stress caused by ship-induced waves are the main culprits of bank erodibility. The numerical results show that by approaching the Frc, the increasing rate of drawdown reaches its maximum causing a jump in the force of total pressure, which in turn gives a rise to a peak in the shear stress on the waterway bank.

Research on Gear Flank Twist Compensation of Continuous Generating Grinding Gear Based on Flexible Electronic Gearbox

Gear flank twist occurs when threaded wheel grinds crowning lead modified helical gears, which reduces gear machining accuracy. To overcome this problem, a flank twist compensation method based on flexible electronic gearbox is proposed in this paper, the method can reduce the degree of twist and improve gear machining accuracy. Firstly, flank equations of gear and threaded wheel are established, coordinates and normal vectors of gear flank are used to represent twist. Secondly, coordinate transformation matrix between workpiece and tool coordinate system is established based on multi-body system theory and homogeneous coordinate transformation, and relationship between coordinates and normal vectors of gear flank and master-slave axis (B-axis, C-axis, X-axis, Y-axis, Z-axis) movement amount is obtained by inverse kinematics and electronic gearbox, then master-slave axis movement compensation amount between crowning lead modified flank and twisted flank is obtained. Finally, twist is compensated by compensating for master-slave axis movement amount, and flank contact analysis based on KISSsoft is carried out to observe normal force and contact stress of flanks. This paper uses inverse kinematics and electronic gearbox to realize flank twist compensation, which makes up for long period and high cost of traditional flank twist compensation by changing shape of threaded wheel. Simulation results show that this method can effectively compensate for flank twist and improve accuracy and efficiency when threaded wheel grinds crowning lead modified helical gears.

Response of a semiconducting medium under photothermal theory due to moving load velocity

The present research article deals with the study of steady-state response due to moving load in a semiconducting medium under photothermal theory. The applied load is moving with constant speed U for an infinitely long time over the free surface of a homogeneous semiconducting medium. The governing equations of motion and heat conduction equation have been solved analytically. The effects of the velocity of the moving load and thermoelectric coupling parameter on displacement components, force stress, carrier density, and temperature distribution have been investigated. Numerical results obtained from the present study are presented graphically for normal displacement, normal force stress, carrier density, and temperature distribution.

Plane wave propagation in a semiconducting medium under photothermal theory

In the present investigation, surface wave propagation in a semiconducting medium under photothermal theory has been discussed. A non-viscous fluid of uniform thickness is overlying the infinite semiconducting half-space. The governing equations for the above problem are solved for surface wave solutions. A mechanical force of constant magnitude is applied along the interface of two media. The components of displacement, stresses, carrier density, and temperature distribution at the interface are obtained for the semiconducting medium. The effect of the thermoelectric coupling parameter is also shown on the penetration depth of various waves. Also, the effect of fluid layer depth is depicted by the graphical results for normal displacement, normal force stress, carrier density, and temperature distribution.

Experimental and theoretical investigation into surface roughness and residual stress in magnetorheological finishing of OFHC copper

Highly finished copper surface without any appreciable residual stress is in high demand in electronics, space, and optical industries. Conventional finishing processes are not suitable for the finishing of copper owing to its extremely lower hardness. In the present study, wheel based magnetorheological finishing (MRF) process is used to attain nanolevel surface roughness of oxygen-free high conductivity (OFHC) copper. The wheel speed, working gap and feed rate are selected as the main controlling process parameters. Areal surface roughness ( S a ), normal force, tangential force and residual stress are studied as the response parameters. The measurement of residual stress has a significant importance as it may affect the optical properties of the finished surface. The residual stresses and phases of all the finished surfaces are analysed using X-ray diffraction (XRD) technique. A theoretical model is proposed to predict the surface roughness of the MRF processed surfaces. It is observed that a nanolevel surface roughness with lower residual stress can be attained by performing MRF with a higher working gap, and lower wheel speed and feed rate. In the present study, a minimum surface roughness ( S a ) of 15.5 nm and compressive residual stress of 6.9 MPa are attained on the OFHC copper surface.

Pulsed laser heating of a thermoelastic micro-stretch medium under the effect of a magnetic field in the context of a dual-phase-lag model

This investigation is to study the effect of magnetic field and thermal loading due to pulsed laser heating on a rotating micro-stretch thermoelastic medium. The bounding plane surface is heated by a non-Gaussian laser beam. The problem is studied in the context of the dual-phase-lag model, Lord and Shulman theory and Green–Naghdi theory of type II. The normal mode analysis is used to solve the problem to obtain the exact expressions for the displacement components, the micro-rotation, normal force stress, tangential couple stress and temperature distribution. All quantities in the presence and the absence of magnetic field and two values of time in the presence rotation are shown graphically.

Effect of magnetic field and gravity on two-temperature thermomicrostretch elastic medium under dual-phase lag model

The present paper is concerned with the propagation of plane waves in an isotropic two-temperature generalized thermomicrostretch elastic solid half-space in the context of the dual-phase lag model, Green–Lindsay and coupled theories. The governing equations are solved to show the effect of a magnetic field, the gravity and the two-temperature on the medium. The normal mode analysis is used to solve the problem to obtain the exact expressions for the displacement components, the microrotation, the normal force stress, the tangential couple stress, the temperature distribution and the conducting temperature. All quantities in the presence and absence of the magnetic field and gravity, as well as the two-temperature, are shown graphically.

Internal heat source in a temperature dependent thermoelastic half space with microtemperatures

A two dimensional deformation due to internal heat source in a thermoelastic solid with microtemperatures under the dependence of modulus of elasticity and thermal conductivity on reference temperature has been studied. A mechanical force of constant magnitude is applied at the free surface of thermoelastic half space. The normal modes technique has been applied to obtain the exact expressions for the components of normal displacement, microtemperature, normal force stress, temperature distribution, heat flux moment tensor and tangential couple stress for thermoelastic solid with microtemperatures. The effect of internal heat source, thermal conductivity and microrotation on the derived components have been derived analytically. The graphical results are shown in the presence and absence of thermal conductivity and microrotation to show the appreciable effect of rotation and temperature on the quantities. The problem may also be extended to show the effect of different types of mechanical and thermal sources applied in the medium.

Dynamic characteristics of binary sphere mixtures under air impact

This paper presents a numerical study on the packing densification process of binary sphere mixtures under air impact using a combined computational fluid dynamics and discrete element method (CFD-DEM) scheme. The effects of particle size ratio (PSR) on the force and stress characteristics including the depth-averaged normal force, probability density function (PDF) of normal forces, distributions of strong forces, mean stress distribution in the axial cross-section, and depth-averaged mean stress for various contact types, are comprehensively analyzed. In addition, the distribution of fluid-particle interaction forces is also discussed to explain the densification mechanism during air impact. The results reveal that the force and stress characteristics are significantly affected by both PSR and air impact. For each PSR, the packing density increases with the gas inlet velocity to a maximum and then decreases. Meanwhile, both the depth-averaged normal force and the mean stress in initial packing increase linearly with the depth, while the relationship between the depth-averaged normal force or mean stress and the depth is in power law growth in the final packing after air impact. The contact type of L-S (L-large sphere, S-small sphere) plays a leading role in the PDF of normal forces, while the effects of S-S contact type on the packing system is weak. Furthermore, apart from the L-L contact, the strong force percentage of other contacts increases after air impact densification. The air impact can effectively improve the uniformity of the normalized mean stress distribution for the packing of binary mixtures. Finally, the distribution of fluid-particle interaction forces demonstrates that the packing can be densified by obvious rearrangement of small particles for adjacent pore filling, and this trend will become more apparent with the increase of PSR.

Effect of Thermoelectric Coupling Parameter in a Semiconducting Medium Under Photothermal Theory

The purpose of this paper is to study the two dimensional deformation in a semi-infinite semiconducting medium. The deformation is caused subjected to a mechanical force applied along the interface of elastic layer of thickness h and a semiconducting medium. Normal Mode analysis has been used to obtain the exact expression of normal displacement, normal force stress, temperature distribution and carrier density. The effect of this force and thermoelectric coupling parameter on the displacement component, force stress, temperature distribution and carrier density has been depicted graphically.

Response of Thermoelastic Micropolar Cubic Crystal under Dynamic Load at an Interface

The purpose of this paper is to study the two dimensional deformation in a thermoelastic micropolar solid with cubic symmetry. A mechanical force is applied along the interface of a thermoelastic micropolar solid with cubic symmetry (Medium I) and a thermoelastic solid with microtemperatures (Medium II). The normal mode analysis has been applied to obtain the exact expressions for components of normal displacement, temperature distribution, normal force stress and tangential coupled stress for a thermoelastic micropolar solid with cubic symmetry. The effects of anisotropy, micropolarity and thermoelasticity on the above components have been depicted graphically.

Effect of mechanical force along the interface of semi-infinite semiconducting medium and thermoelastic micropolar cubic crystal

AbstractThe present investigation deals with the two-dimensional deformation in a thermoelastic micropolar solid with cubic symmetry at the interface of the semi-infinite semiconducting medium under photothermal theory. A mechanical force is applied along the interface. The analytic expressions for the components of normal displacement, temperature distribution, normal force stress, and tangential couple stress for a thermoelastic micropolar solid with cubic symmetry have been obtained using normal mode analysis technique. The effect of anisotropy, microrotation, and thermoelasticity on the derived components have been depicted graphically.

Plane strain problem in a rotating microstretch thermoelastic solid with microtemperatures

A two-dimensional problem in an infinite microstretch thermoelastic solid with microtemperatures subjected to a mechanical source is studied. The medium is rotating with a uniform angular velocity ??. The normal mode analysis is used to obtain the exact expressions for the component of normal displacement, microtemperature, normal force stress, microstress tensor, temperature distribution, heat flux moment tensor and tangential couple stress. The effect of microrotation and stretch on the considered variables are illustrated graphically.

Numerical Research on the Pullout Failure of GFRP Bolt

The fiber pullout is a main failure after the fiber is broken in the tension of glass fiber reinforced polymer (GFRP) bolt. In this paper, the numerical analysis is done on the distribution of both fiber normal force and interface shear stress. The results show that, on the ideal interface, the fiber pullout occurs from the lower end to the upper end of the matrix gradually, and both the normal stress of the fiber and the shear stress of the ideal interface gradually increase from the lower end to the upper end. With the increase of the interface layer thickness, the shear stress concentration area on the interface is enlarged while the stress applied is reduced, and the displacement of GFRP deformation is increasing sharply. This means that the capacity of GFRP deformation is enhanced. As a soft elastic body, the interface layer with a smaller elastic modulus can make the fiber stress and the interface shear stress sharply small and well dispersed. In addition, the load can be effectively transferred to the reinforced phase fibers in a bigger interfacial layer elastic modulus with a certain strength.

Two-temperature plane strain problem in a semiconducting medium under photothermal theory

In this investigation, we study the two-temperature problem with two-dimensional (2-D) deformations for a semi-infinite semiconducting medium at the free surface with the influence of mechanical force through a photothermal process. The harmonic wave method (Normal Mode analysis) has been used to get the exact expression of normal displacement, normal force stress, carrier density, and temperature distribution, and also the two-temperature coefficients ratios has been obtained analytically. The effects of several parameters as thermoelastic and thermoelectric coupling parameters and two-temperature parameter of this force on the displacement component, force stress, carrier density, and temperature distribution have been depicted graphically.

Internal Heat Source in Thermoelastic Microelongated Solid Under Green Lindsay Theory

Abstract The present study deals with two dimensional deformation, due to internal heat source in a thermoelastic microelongated solid. A mechanical force is applied along the interface of elastic half space and thermoelastic microelongated half space. The problem is in the context of Green Lindsay (GL) theory. The analytic expressions for displacement component, normal force stress, temperature distribution and microelongation have been derived. The effect of internal heat source and microelongation on the derived components have been depicted graphically.

Two dimensional deformation in microstretch thermoelastic half space with microtemperatures and internal heat source

AbstractThe purpose of this paper is to study the two dimensional deformation due to internal heat source in a microstretch thermoelastic solid with microtemperatures (MTSM). A mechanical force is applied along the interface of fluid half space and microstretch thermoelastic half space. The normal mode analysis has been applied to obtain the exact expressions for component of normal displacement, microtemperature, normal force stress, microstress tensor, heat flux moment tensor, and couple stress for MTSM. The effect of internal heat source, micropolarity, and microstretch on the above components has been depicted graphically.

Response Due To Impulsive Force In Generalized Thermomicrostretch Elastic Solid

A two dimensional Cartesian model of a generalized thermo-microstretch elastic solid subjected to impulsive force has been studied. The eigen value approach is employed after applying the Laplace and Fourier transforms on the field equations for L-S and G-L model of the plain strain problem. The integral transforms have been inverted into physical domain numerically and components of normal displacement, normal force stress, couple stress and microstress have been illustrated graphically.

Response Due to Concentrated Force in Micropolar Elastic Solid with Voids

Abstract The eigen value approach, following Laplace and Fourier transforms has been employed to find the general solution of the field equation in a micropolar elastic solid with voids for the plane strain problem. An application of an infinite space with impulsive force has been taken to illustrate the utility of the approach. The integral transformations have been inverted by using a numerical inversion technique to get result in physical domain. The result in the form of normal displacement, volume fraction, normal force stress, tangential force stress and tangential couple stress components has been obtained numerically and illustrated graphically to depict the effect of micropolarity and voids.

Interaction Due to Mechanical Source in Generalized Thermo Microstretch Elastic Medium

The eigen value approach, following the Laplace and Hankel transformation has been employed to find a general solution of the field equations in a generalized thermo microstretch elastic medium for an axisymmetric problem. An infinite space with the mechanical source has been applied to illustrate the utility of the approach. The integral transformations have been inverted by using a numerical inversion technique to obtain normal displacement, normal force stress, couple stress and microstress in the physical domain. Numerical results are shown graphically