Papers by Keyword: Contact Force

Abstract: Since that rollers of a certain type of bridge inspect vehicle were worn seriously in the process of using, a multi-contact dynamic model was set up utilizing ADAMS and SolidWorks. The Poison Model was used to describe the contact relationship between rollers and vertical truss. After dynamic analysis and calculation of contact forces by ADAMS, time-contact force curves were drawn. The curves proved that the results were consistent with the actual situation, so that the simulation process was verified.

Abstract: The influence of the clearance in the joint must be considered in the modeling and dynamic analysis for the mutibody mechanical systems. The model of the planar revolute clearance joint is built on the base of the clearance vector approach and the continuous contact approach. Furthermore, the friction is included through the modified Coulombs friction law and the lubrication is introduced into the model, with the Reynolds equation employed to evaluate the hydrodynamic forces. A slider-crank drive system of a screen printing machine with a clearance joint is researched as the example, whose dynamic characteristics are simulated by the software ADAMS. It is shown that the clearance has affected the dynamics response of the system and the lubrication is effective to deaden the impact.

Abstract: To better understand the bristle behavior and leakage performance in brush seals, a Computational Fluid Dynamics (CFD) model has been developed, in which the brush is treated as an anisotropic porous region with nonlinear resistance coefficients. With the calculated pressure distribution and the cantilever beam theory, aerodynamic and contact forces on bristles are calculated utilizing the Finite Element Method; and bristle deflections in the axial direction and in the orthogonal plane are obtained. Subsequently their influences on friction force and torque are evaluated. Computed different kinds of low hysteresis brush seals, discuss the effect of size parameters of front plate and back plate on low hysteresis brush seals.

Abstract: The effect of contact between the sliders and disks on the flying characteristics of sliders in hard disk drives was modeled and analyzed. The differential equation of motion for slider was constructed based on slider/disk dynamics model with consideration of contact force. The contact was simplified as an elastic contact style and described by Hertzian contact method. The slider responses were simulated by using SimMechanics software. The results indicate that slider acts as periodic vibration under the contact force.

Abstract: A 2-dimensional granular assembly, subjected to isotropic consolidation and biaxial compression, is simulated by applying discrete element method and the particle flow code of PFC2D. The contact force network and distribution are examined and compared to an analogous photoelastic experiment carried out by other studies. The current study shows that the assembly undergoes dilatation and strain-softening after peak strength, and the coordination number (average contact number of particles) increases a little in the initial stage of strain hardening followed by a sharp dropping before the onset of softening. This is correlated with the contact force chain establishment and the evolution of structural anisotropy. The distribution of the normal force and the ratio of tangential to normal force for both the isotropically compressed and sheared stages indicates that the strong normal contacts are crucial for the force chain transmitting stress through assembly. The angular distribution of the contact forces supported this point and could help visualizing the induced anisotropy. These issues are vital for gaining a deeper understanding of the macroscopic behavior of granular material from microscopic analysis.

Abstract: An accurate finite element contact analysis of helical gears was done directly under ANSYS, while the integrated elastic deformation of the meshed teeth was extracted directly from the finite element contact analysis results, and considered as the main basis of the amount of tooth profile modification. Linear, conic, cubic, and sine relief curve are compiled and established in MATLAB, on which gear models of two ways of modified gear are built. Under the same modified parameters, contact method is used on the proposed finite element models of gears by software LS-DYNA, and the effect of the two ways of gear relief on contact force on teeth face is analyzed. The results show that the effect of a pair of gears relief is better than one gear relief for linear and conic relief curve, and the effect of one gear relief is better than a pair of gears relief for cubic and sine relief curve. So dynamic simulation on modified involute gears has great significance for reducing contact force of teeth face of gears.

Abstract: Linear, conic, cubic, and sine relief curve are compiled and established in MATLAB, on which gear models are built in UG and a new method of establishing relief gear models is proposed in this paper. Based on the theory of elastic, contact method is used on the proposed finite element models of gears by software LS-DYNA. Total contact force of teeth face, contact force of single tooth and equivalent stress on relief gears in different cases are obtained. The results show that contact impact existing in meshing between teeth of gears is ameliorated, contact force of tooth face and equivalent stress is reduced. The effect of cubic and sine relief curve is the best. So dynamic simulation on relief gears has great significance for reducing contact force between teeth faces of gears.

Abstract: A method was developed to predict numerically the dent depth of composite laminates subjected to quasi-static indentation. A progressive damage analysis was conducted for composite laminates under quasi-static transverse compressive loading by using a strain based Hashin and Yeh failure criteria as well as the FEM, and a series of degraded elastic constants of the damaged zone were drawn from the numerical results. The effective elastic constants of the damaged zone of the laminates were reevaluated according to Sun’s explicit expression. Finally, the dent depth vs. indentation force curve was predicted based on Swanson’s contact theory. The numerical simulations on the static indentation tests of T700/BA9912, T700S/5228 and T700/QY9511 laminates were done via this method. The numerical results agree well with the test data in the terms of the contact force and the corresponding dent depth.

Abstract: For polishing friable complex transparent pieces surface, compliant mechanism is used on the polishing robot in this paper. Compliant mechanisms on the polishing robot are designed and installed. Polishing experiments are carried out without compliant mechanisms and with compliant mechanisms. The experiments results show that the robot can complete better polishing tasks with compliant mechanisms, through the wrist force sensor collecting the polishing force, and controlling the proper compression height of compliant devices.

Abstract: This paper presents a systematic research on the gear transmission system of the electric vehicle. An accurate 3-D model of the gear transmission system is established in UG (Unigraphics NX) using software Gearwizard, and then imported to ADAMS/View environment. Based on the contact force of ADAMS, the vibration at 3 different test points of the model are simulated. The simulation results seem to be in good accordance with the test results, which proved the validity of the gear transmission model. Finally, the influence of helix angle on vibration at 3 different test points are also researched. The results of the total analysis can be used further to optimize the gear transmission system of the electric vehicle.