Papers by Keyword: Elastic Contact

Abstract: This work is devoted to the elaboration of the new methodology for the wear parts contact estimation using 3D surface roughness parameters defined in the standard ISO 25178-2:2012 for friction and wear rate determination. In our research the random surface model was used, where the height of surface asperities h (x,y) has a normal probability distribution. As a result of research the equations for estimation of the elastic contact area and friction coefficient were derived. The existence of the correlation between friction coefficient and 3D surface roughness parameters was proven as well. The results of this work could have wide practical application, for example in design, for the texture specification on drawings, calculation of load, etc.

Abstract: The most commonly used method for the analysis of instrumented indentation test (Oliver-Pharr) is based on isotropic elastic solution of contact problem which is not necessarily valid when indenting at the scale of one (anisotropic) grain. In this paper, we performed the grid indentation method at the sub-micron scale (at low indentation load and depth of penetration) on an area containing several grains with different crystallographic orientation which was simultaneously characterized by electron back-scattered diffraction. Measured dependencies of hardness and indentation modulus on crystallographic orientation were compared with analytical solution and finite element simulations.

Abstract: A shape optimization method for solving elastic contact problems is proposed based on gradient-less idea(a zero order optimization method). It is found that the contact stress on the elastic contact surface can be smoothed and reduced effectively by both changing the contact surface shape and changing the shape of non-contact surface. To avoid mesh distortion that results in undesirable shape, a move stratrgy for nodal movement has been used in the finite element model. Two examples are presented to show the effectiveness of the proposed method in dealing with elastic contact problems.

Abstract: In this study the tangential contact stiffness between two elastic bodies having nominally flat surfaces with different material combinations is investigated. The tangential contact stiffness between these two elastic bodies is first calculated based on the Greenwood-Williamson-McCool contact theory. Then, the tangential contact stiffness is determined by experimental investigation on a tribometer under the effect of different values of normal load and tangential displacement amplitude. The tangential contact stiffnesses obtained from the experimental data show a good agreement with the theoretical results, where the trends are similar and they are in the same order of magnitude.

Abstract: A calculation method of wheel-rail multi-point contact based on the elastic contact model is introduced. Moreover, the simulation calculation of vehicles passing through branch lines of No.18 turnouts is carried out. The result showed that the acute change of wheel-rail normal force caused by the transfers of wheel-rail contact point between two rails can be avoid by wheel-rail multi-point contact method, and the transfers of wheel-rail normal force between two rails is smoother. The validity of wheel-rail multi-point contact method is verified.

Abstract: The theoretical value of bolt pre-tightening torque coefficient is typically 0.2 on load boundary condition simulations.A set of measuring setup has been designed in present study.Through direct measurement and electric measurement,a torque coefficient of 0.15 has been measured.The effects of pre-tightening torque coefficient on bolt stress field are studied numerically.Results show that the coefficient has significant effect on bolt stress fields and relatively conservative results will be achieved if a theoretical value of 0.2 is chosen.Studies on stresses around hole-edge and comparisons with test values show that simulated results of and agree well with test data and the relative errors are no more than 15%.

Abstract: The article concerns dynamics and vibration of a high power rotating system with toothed wheel coupling that inserts elastic plate packets. Theoretical modeling and simulation of the rotating system with toothed wheel coupling have been provided by a finite element method. Complex model involved a rotating system, hydrodynamic bearings and coupling. The dynamics of semi-couplings and plates have been simulated. Experimental measurement of vibration has been measured with stationary machine condition monitoring and a diagnostic system.