Dynamics of spatial flexible multibody systems with clearance and lubricated spherical joints

Abstract

A computational methodology for analysis of spatial flexible multibody systems, considering the effects of the clearances and lubrication in the system spherical joints, is presented. The dry contact forces are evaluated through a Hertzian-based contact law, which includes a damping term representing the energy dissipation. The frictional forces are evaluated using a modified Coulomb's friction law. In the case of lubricated joints, the resulting lubricant forces are derived from the corresponding Reynolds' equation. An absolute nodal formulation is utilized in flexible body formulation. The generalized-α method is used to solve the resulting equations of motion. The effectiveness of the methodology is demonstrated by two numerical examples.

On the continuous contact force models for soft materials in multibody dynamics

“…This fact is not surprising because, for instance, Lankarani and Nikravesh [33] derived their model for high values of restitution coefficient, being, therefore, valid for hard contacts, such as those between metals [49][50][51][52]. The values of the coefficient of restitution for soft materials are low or medium [40,43,48,53], which clearly indicate that the hysteresis damping factor given by (6) and (8) cannot be used.…”

Investigation on Dynamics of Mechanical System with Clearance Joint

“…The contact force model in clearance joint uses the nonlinear contact force mode given by Equation (8). The values of the clearance size are considered as 1mm, 0.5mm, 0.25mm and 0.1 mm.…”

“…It is known as a source of impact forces and these forces not only create increasing vibration amplitude, but also reduce system reliability, stability, life, and precision [1][2][3][4]. These clearances modify the dynamic responses of the system, justify the deviations between the numerical predictions and experimental measurements and eventually lead to significant vibrations of the real mechanism [5][6][7][8][9][10][11].…”

Multibody modeling of non-planar ball bearings

“…Studies dealing with the use of physical joint in multibody dynamic simulation are of growing interest. In multibody simulation, real cylindrical or spherical joint have been used [11,12]. A recent work proposes a model of planar deep groove ball bearing that can be used in planar multibody system [13].…”

“…If we assume a traction of the form (12), then the relative displacements inside the elliptical area E are polynomials in x and y of the same degree. Polynomial coefficients (a mn , b mn ) and (d pq , e pq ) are linked linearly.…”