Analysis of the influence of design parameters on the agro-ecological qualities of tractor tires

Experimental studies of the impact of agricultural mobile machinery movers on the soil are seasonal in nature and require complex experimental equipment. The complexity of the physical processes occurring in the elastic wheel-ground system requires the introduction of many assumptions and limitations that reduce the accuracy of the results, according to the design of simulation models performed in the software environment. The aim of the research was to study the influence of the design parameters of the tire on the efficiency of the normal deflection along the contact spot zone X. Studies have shown that 65% to 77% of the normal deflection of the tire is used when passing the contact spot. The reinforcement parameters of the tire frame have the greatest impact on the efficiency of the normal deflection along the contact spot zone. With an increase in the number of layers of the frame cord from 2 to 8, the coefficient of usability of the normal deviation for the stroke of the contact spot decreases from 0.761 to 0.689, with an increase in the angle of inclination of the frame cords - decreases from 0.755 to 0.693.

Bending of a ribbed plate under complex loading

The article considers the problem of a rectangular plate, supported by a cross system of stiffening ribs, bending. In addition to the transverse load, the plate is subjected to forces in its plane, transmitted through the ribs. Аn analytical solution to the boundary value problem for the resolving differential equation with respect to the normal deflection of the plate, describing the deformation of a rectangular plate supported by stiffeners, is obtained. The solution is presented in the form of series in combinations of regular and special discontinuous functions, which converge quickly and lead to a simple computational algorithm. The influence of the ribs is taken into account in the equation in the form of additional terms containing factors with a delta function. This approach allows us to get rid of a number of assumptions regarding the interaction of the plate with its reinforcing elements. The use of the apparatus of generalized functions when modeling objects of this type simplifies the boundary conditions (there are no conditions for conjugation of various structural elements), but at the same time the differential equations become more complicated. The problem is reduced to the so-called partially degenerate equations. Development of analytical methods that allow obtaining exact solutions of differential equations of this type, and their introduction into computational practice, is one of the urgent tasks of the mechanics of objects with disturbed regularity.

Analytic and Numerical Results of Bending Deflection of Rectangular Composite Plate

In this chapter, the derivation of analytic formulation of bending deflection has been done using the theory of classical laminate plate. The method of Navier and Levy solutions are used in the calculation. The composite laminate plate is exposed to out-off plane temperatures and combined loading. The temperature gradient of thermal shock is varied between 60C∘ and −15C∘. The combined loading are the bending moment (Mo) in the y-direction and in-plane force (Nxx) in the x-direction. The in-plane force (Nxx) has a great effect on the bending deflection value within a 95.842%, but the bending moment (Mo) has a small effect on the bending deflection value in the rate of 4.101%. The results are compared and verified for central normal deflection.

Characterization of Exponential Cohesive Zone Model for Fracture Assessment of De-Bonded Composite Panels

Composite structures are prone to delamination/de-bond and effective tool to simulate de-lamination is cohesive zone model. Cohesive zone model uses multiple adhesive failure parameters. The influence of adhesive parameters on the delamination and fracture of Double cantilever Beam, subjected to Mode-I loading through finite element simulations is studied usingExponential Cohesive Zone Model (ECZM). Influence of Normal stress (σ), normal deflection (δn) and tangential deflection (δt) on the de-bond propagation is examined.From the analysis it is found that the tangential deflection (δt) has negligible impact on Mode-I loading and fracture of the specimen. Significant effects are seen for the perturbation of Normal stress (σ) and Normal deflection (δn). A Finite element based ECZM for composite layer (HTS/M18) with EPG 2601 adhesive is proposed. The model is validated by comparing with test data.

Modeling Methodology of Flexible Milling Force for Thin-Walled Component on High Speed Peripheral Milling Processing System

This study has developed a model in order to show the relationship between deflection of the low-rigidity processing system such like thin-walled component and the flexible milling force. The new model takes the deflection of cutter-workpiece system into account. The cutting force is analyzed simulatively by utilizing modified Newton–Raphson iterative algorithm. The simulative results show that the total normal deflection of workpiece–cutter system is the main factor affecting the change of cutting force.

Simultaneous Measurement of Surface Topography and Friction Force by a Single-Head Lateral Force Microscope

Although friction force measurements using one sensor to detect both the normal deflection and rotation angle of a scanning probe are convenient and popular, the critical issues regarding the calibration of the instruments have not been fully studied. A Lateral Force Microscope (LFM), modified from the Point Contact Microscope (PCM), is used to simultaneously measure the surface topography and friction force. An optical head is used to measure the normal bending deflection and rotation angle of the cantilever that carries the diamond tip. Emphasis is put on the development of reliable calibration procedures for obtaining the normal deflection and rotation sensitivities of the optical head as well as the spring constants in the bending and torsion modes. The friction loop, which is essential for friction measurements, is investigated in detail. The LFM is used to measure a two-phase composite to show its ability to distinguish different materials on a surface. Wear tests on a single-crystal silicon <100> surface show different friction coefficient regimes, depending on the applied load. For small loads, there is no wear and the friction coefficient is constant. For larger loads, the friction coefficient and wear depth increase with normal load.

The Rayleigh Bearing

Common bearing theory cannot be applied to a Rayleigh bearing which we place at 0<y<h1forx<0,0<y<h2forx>0,h1>h2,(1) near x = 0. This paper is concerned with a more exact theory, providing (partial) differential equations whose solution can handle even the region near x = 0. In section 1, after the ordinary, approximate solution is reviewed, more exact equations are obtained for the flow, under the assumptions that the flow is nonturbulent, that the fluid is incompressible, and that its viscosity μ is constant. It is shown that the streamline function ψ is biharmonic, that it is a solution of the repeated Laplace equation ∇4ψ=∇2(∇2ψ)=0,(2) and proper boundary conditions are obtained for it. In section 2 it is recalled that equation (2) also occurs in certain plate problems, such as the normal deflection of a constant thickness plate given by equations (1), free from distributed normal load, and subject to proper deflections and slopes at its boundary. Again, equation (1) is also satisfied by Airy function H of the plate (1) subjected to normal and shearing tractions over its boundary. Based on the above, analogies are outlined between the fluid flow and the two plate problems, with ψ corresponding to ω and to H. These analogies can be used to obtain experimental solutions of the bearing flow problem. Section 3 is devoted to graphical and numerical solutions. The numerical methods are based on covering the area (1) with a square mesh, and approximating to the differential operators by finite difference quotients of values at the mesh points, yielding to a set of linear equations. These are solved either on a computer, or by assuming a solution and improving it successively. The graphical method involves conformal mapping of (1) onto a plane with a simpler boundary, such as an infinite strip. This can be carried out analytically, or graphically by means of two sets of orthogonal curves cutting (1) into small squates. Section 4 utilizes separate expansions of ψ in product biharmonics to each side of x = 0, and joining them up so that the integrated errors over x = 0 are minimized. Finally in Section 5 the biharmonic ψ is expressed in the form ψ=F+yG(3) where F and G are harmonic, and from the boundary conditions on ψ are obtained boundary values of F, G and/or their conjugate harmonics. The methods used involve Green’s functions and therefore are carried out best in the plane of the infinite strip.

The Half-Space Under Pressure Distributed Over an Elliptical Portion of Its Plane Boundary

In determining the safety of foundations the assumption is usually made that the pressure distribution on the ground, in general unknown, is closely approximated by a constant one. Mathematically, the problem is thereby reduced to finding the components of stress and displacement in a half-space due to a uniform pressure on a portion of its plane boundary. The present paper contains an investigation of this problem for the case of loading over an area bounded by an ellipse. Two of the results are: (a) On the normal to the loading area through its center, the two principal stresses in planes parallel to the undeformed surface, compressive on and near the surface, become tensile within a depth smaller than the length of the corresponding principal axis of the loading area; (b) the normal deflection of the surface is greater at the extremity of the minor axis of the loading area than at the extremity of the major axis, the difference between the two values increasing with the ellipticity of the bounding curve.

The capture and loss of electrons by α-particles

In a recent paper the writer presented evidence of α-particles bearing a single positive charge and of α-particles which were neutral. These were found by deflecting α-particles by a magnetic field in a good vacuum and registering them photographically on Schumann plates. A band appeared on the plate deflected only half the amount of the regular a-particle band. This was ascribed to α-particles, which had captured electrons in passing through an absorbing screen and thus were singly-charged. The behaviour of these particles was described qualitatively. The proportion of singly- to doubly- charged particles increased rapidly as their velocity decreased. From the effects of air in the path of the α-particles it was suggested that each particle must capture and lose electrons many times. Sir E. Rutherford has recently published the results of a very interesting quantitative study of these particles by the scintillation method. By electrostatic deflection of the beam he showed that the particles undergoing only half the normal deflection must be singly-charged α-particles and nothing else. By counting methods he found values for the mean free paths for capture and for loss of an electron by the α-particle, and found the way in which these mean free paths varied with the velocity.