A continuous force model for the impact analysis of flexible multibody systems

1987 ◽  
Vol 22 (3) ◽  
pp. 213-224 ◽  
Author(s):  
Y.A Khulief ◽  
A.A Shabana
Keyword(s):  
Multibody Systems ◽  
Impact Analysis ◽  
Flexible Multibody Systems ◽  
Force Model ◽  
Flexible Multibody ◽  
The Impact

A Global Simulation Method for Flexible Multibody Systems With Variable Topology Structures

2015 ◽  
Vol 10 (2) ◽  
Author(s):  
Wenhao Guo ◽  
Tianshu Wang
Keyword(s):  
Multibody Systems ◽  
Simulation Method ◽  
Flexible Multibody Systems ◽  
Governing Equations ◽  
Recursive Formulation ◽  
Global Simulation ◽  
Constraint Equations ◽  
Flexible Multibody ◽  
The Impact ◽  
Velocity Level

By means of a recursive formulation method, a generalized impulse–momentum-balance method, and a constraint violation elimination (CVE) method, we propose a new global simulation method for flexible multibody systems with kinematic structure changes. The constraint equations of a pair of adjacent bodies, considering body flexibility in Cartesian space, are derived for a recursive formulation. Constraint equations in configuration space, which are obtained from the constraints presented in this paper via recursive formulation, are very useful for modeling different kinematic structures and impacting governing equations. The novelty is that the impact governing equations, which calculate the jumps of generalized velocities, are modified by taking velocity-level CVE into consideration. Numerical examples are given to validate the presented method. Simulation results show that the new method can effectively suppress constraint drifts at the velocity level and stabilize constraint violations at the position level.

Reduced Isogeometric Analysis Models for Impact Simulations

2021 ◽  
Author(s):  
Tobias Rückwald ◽  
Alexander Held ◽  
Robert Seifried
Keyword(s):  
Isogeometric Analysis ◽  
Multibody Systems ◽  
Degrees Of Freedom ◽  
Computation Time ◽  
Flexible Multibody Systems ◽  
Shape Functions ◽  
Elastic Rod ◽  
Flexible Multibody ◽  
Impact Simulations ◽  
The Impact

Abstract Detailed impact simulations in flexible multibody systems are usually based on isoparametric finite element models. For modeling the dynamics of an impact, a precise representation of the geometry is essential. However, isoparametric finite elements involve the discretization of the geometry. This work tests the isogeometric analysis (IGA) as an alternative approach in flexible multibody systems. The IGA enables the exact representation of the geometry by using non-uniform rational basis splines (NURBS) as element shape functions. In the context of an efficient impact simulation a model reduction and a possible inclusion of the floating frame of reference formulation is beneficial. The degrees of freedom of the flexible bodies are reduced using component mode synthesis to save computation time in the multibody simulation. For the precise description of deformations and stresses in the contact area as well as elastodynamic effects, a large number of global shape functions is required. As testing examples, the impact of two elastic spheres and a multibody multicontact problem including wave propagation in a long elastic rod are simulated and compared to reference solutions.

Modeling and prediction of wear at revolute clearance joints in flexible multibody systems

2013 ◽  
Vol 228 (2) ◽  
pp. 317-329 ◽  
Author(s):  
Bo Zhao ◽  
Zhi-Nan Zhang ◽  
Xu-Dong Dai
Keyword(s):  
Contact Force ◽  
Multibody Systems ◽  
Flexible Multibody Systems ◽  
Force Model ◽  
Wear Prediction ◽  
Clearance Joints ◽  
Modeling And Prediction ◽  
Clearance Joint ◽  
Flexible Multibody ◽  
Flexible Component

This article proposes a numerical approach for the modeling and prediction of wear at revolute clearance joints in flexible multibody systems by integrating the procedures of wear prediction with multibody dynamics. In the approach, the flexible component is modeled based on the absolute nodal coordinate formulation. The contact force in the clearance joint is applied using the continuous contact force model proposed by Lankanrani and Nikravesh and the friction effect is considered using the LuGre friction model. The simulation of wear is performed by an iterative wear prediction procedure based on Archard’s wear model. The radial basis function neural network technique is employed to deal with the pin-on-disc experimental data for obtaining the wear coefficient used in the wear prediction procedure at different contact conditions. The comparison of the wear predicted at the clearance joint in the rigid and flexible planar slider-crank mechanisms demonstrates that the proposed approach can be used to model and predict wear at revolute clearance joints in flexible multibody systems, and the wear result predicted is slightly reduced after taking the flexibility of components into account.

Active vibration control of spatial flexible multibody systems

2013 ◽  
Vol 30 (1) ◽  
pp. 13-35 ◽  
Author(s):  
Maria Augusta Neto ◽  
Jorge A. C. Ambrósio ◽  
Luis M. Roseiro ◽  
A. Amaro ◽  
C. M. A. Vasques
Keyword(s):  
Vibration Control ◽  
Multibody Systems ◽  
Active Vibration Control ◽  
Flexible Multibody Systems ◽  
Flexible Multibody ◽  
Active Vibration

scholarly journals Dynamics of Multibody Systems With Spherical Clearance Joints

2005 ◽  
Author(s):  
P. Flores ◽  
J. Ambro´sio ◽  
J. C. P. Claro ◽  
H. M. Lankarani
Keyword(s):  
Contact Force ◽  
Multibody Systems ◽  
Contact Forces ◽  
Force Model ◽  
Clearance Joints ◽  
Continuous Contact ◽  
Clearance Joint ◽  
Contact Force Model ◽  
Dynamics Of Multibody Systems ◽  
The Impact

This work deals with a methodology to assess the influence of the spherical clearance joints in spatial multibody systems. The methodology is based on the Cartesian coordinates, being the dynamics of the joint elements modeled as impacting bodies and controlled by contact forces. The impacts and contacts are described by a continuous contact force model that accounts for geometric and mechanical characteristics of the contacting surfaces. The contact force is evaluated as function of the elastic pseudo-penetration between the impacting bodies, coupled with a nonlinear viscous-elastic factor representing the energy dissipation during the impact process. A spatial four bar mechanism is used as an illustrative example and some numerical results are presented, being the efficiency of the developed methodology discussed in the process of their presentation. The results obtained show that the inclusion of clearance joints in the modelization of spatial multibody systems significantly influences the prediction of components’ position and drastically increases the peaks in acceleration and reaction moments at the joints. Moreover, the system’s response clearly tends to be nonperiodic when a clearance joint is included in the simulation.

Performance of the Incremental and Non-Incremental Finite Element Formulations in Flexible Multibody Problems

1999 ◽  
Vol 122 (4) ◽  
pp. 498-507 ◽  
Author(s):  
Marcello Campanelli ◽  
Marcello Berzeri ◽  
Ahmed A. Shabana
Keyword(s):  
Finite Element ◽  
Multibody Systems ◽  
Absolute Nodal Coordinate Formulation ◽  
Flexible Multibody Systems ◽  
Large Displacement ◽  
Body Motion ◽  
Absolute Nodal Coordinate ◽  
Flexible Multibody ◽  
The Absolute ◽  
Finite Element Formulations

Many flexible multibody applications are characterized by high inertia forces and motion discontinuities. Because of these characteristics, problems can be encountered when large displacement finite element formulations are used in the simulation of flexible multibody systems. In this investigation, the performance of two different large displacement finite element formulations in the analysis of flexible multibody systems is investigated. These are the incremental corotational procedure proposed in an earlier article (Rankin, C. C., and Brogan, F. A., 1986, ASME J. Pressure Vessel Technol., 108, pp. 165–174) and the non-incremental absolute nodal coordinate formulation recently proposed (Shabana, A. A., 1998, Dynamics of Multibody Systems, 2nd ed., Cambridge University Press, Cambridge). It is demonstrated in this investigation that the limitation resulting from the use of the infinitesmal nodal rotations in the incremental corotational procedure can lead to simulation problems even when simple flexible multibody applications are considered. The absolute nodal coordinate formulation, on the other hand, does not employ infinitesimal or finite rotation coordinates and leads to a constant mass matrix. Despite the fact that the absolute nodal coordinate formulation leads to a non-linear expression for the elastic forces, the results presented in this study, surprisingly, demonstrate that such a formulation is efficient in static problems as compared to the incremental corotational procedure. The excellent performance of the absolute nodal coordinate formulation in static and dynamic problems can be attributed to the fact that such a formulation does not employ rotations and leads to exact representation of the rigid body motion of the finite element. [S1050-0472(00)00604-8]

Sign in / Sign up

Export Citation Format

Share Document