Efficient Parallel Simulation of Large Flexible Body Systems With Multiple Contacts

2013 ◽  
Vol 8 (4) ◽  
Author(s):  
Naresh Khude ◽  
Ilinca Stanciulescu ◽  
Daniel Melanz ◽  
Dan Negrut
Keyword(s):  
Flexible Multibody Dynamics ◽  
Contact Problems ◽  
Analytical Framework ◽  
Computational Effort ◽  
Flexible Body ◽  
Force Model ◽  
Processing Unit ◽  
Continuous Contact ◽  
Finite Element Software ◽  
Deformable Bodies

This contribution outlines a computational framework for the analysis of flexible multibody dynamics contact problems. The framework combines a flexible body formalism, specifically, the absolute nodal coordinate formulation (ANCF), with a discrete continuous contact force model to address many-body dynamics problems, i.e., problems with hundreds of thousands of rigid and deformable bodies. Since the computational effort associated with these problems is significant, the analytical framework is implemented to leverage the computational power available on today's commodity graphical processing unit (GPU) cards. The framework developed is validated against commercial and research finite element software. The robustness and efficiency of this approach is demonstrated through numerical simulations. The resulting simulation capability is shown to result in 2 orders of magnitude shorter simulation times for systems with a large number of flexible beams that might typically be encountered in hair or polymer simulations.

A Parallel GPU Implementation of the Absolute Nodal Coordinate Formulation With a Frictional/Contact Model for the Simulation of Large Flexible Body Systems

2011 ◽  
Author(s):  
Naresh Khude ◽  
Dan Melanz ◽  
Ilinca Stanciulescu ◽  
Dan Negrut
Keyword(s):  
Frictional Contact ◽  
Absolute Nodal Coordinate Formulation ◽  
Analytical Framework ◽  
Computational Effort ◽  
Contact Model ◽  
Flexible Body ◽  
Processing Unit ◽  
Absolute Nodal Coordinate ◽  
Deformable Bodies ◽  
The Absolute

This contribution discusses how a flexible body formalism, specifically, the Absolute Nodal Coordinate Formulation (ANCF), is combined with a frictional/contact model using the Discrete Element Method (DEM) to address many-body dynamics problems; i.e., problems with hundreds of thousands of rigid and deformable bodies. Since the computational effort associated with these problems is significant, the analytical framework is implemented to leverage the computational power available on today’s commodity Graphical Processing Unit (GPU) cards. The code developed is validated against ANSYS and FEAP results. The resulting simulation capability is demonstrated in conjunction with hair simulation.

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.

Flexible Multibody Dynamics Formulation by Hamilton’s Equations

2010 ◽  
Author(s):  
Martin M. Tong
Keyword(s):  
Multibody Dynamics ◽  
Multibody System ◽  
Mass Matrix ◽  
Equations Of Motion ◽  
Flexible Multibody Dynamics ◽  
Flexible Body ◽  
Flexible Multibody System ◽  
Generalized Coordinates ◽  
Flexible Multibody ◽  
The Matrix

Numerical solution of the dynamics equations of a flexible multibody system as represented by Hamilton’s canonical equations requires that its generalized velocities q˙ be solved from the generalized momenta p. The relation between them is p = J(q)q˙, where J is the system mass matrix and q is the generalized coordinates. This paper presents the dynamics equations for a generic flexible multibody system as represented by p˙ and gives emphasis to a systematic way of constructing the matrix J for solving q˙. The mass matrix is shown to be separable into four submatrices Jrr, Jrf, Jfr and Jff relating the joint momenta and flexible body mementa to the joint coordinate rates and the flexible body deformation coordinate rates. Explicit formulas are given for these submatrices. The equations of motion presented here lend insight to the structure of the flexible multibody dynamics equations. They are also a versatile alternative to the acceleration-based dynamics equations for modeling mechanical systems.

scholarly journals What Causes the Virtual Agglomeration of Creative Industries?

2021 ◽  
Vol 13 (16) ◽  
pp. 9232
Author(s):  
Xu Chen ◽  
Chunhong Liu ◽  
Yao Jiang ◽  
Changchun Gao
Keyword(s):  
Value Chain ◽  
Flexible Manufacturing ◽  
Relevant Literature ◽  
Analytical Framework ◽  
Creative Industries ◽  
Innovative Technology ◽  
Force Model ◽  
Cultural Resources ◽  
Factors Affecting ◽  
Virtual Platform

The agglomeration paradigm for creative industries has fundamentally changed under the digital economy, giving rise to a new form of virtual agglomeration within these industries. This study explores the causes of this virtual agglomeration. We collected online Chinese news texts related to the virtual agglomeration of the creative industry, used text mining to identify nine factors affecting its formation, and refined the internal and external factors for an analytical framework based on the PEST (political, economic, social, technological) and value-chain models. We then combined the relevant literature and the creative industry’s development practices, analyzed the mechanism of each driving factor, and constructed a driving-force model for the creative industry’s virtual agglomeration. The external driving factors were government policy planning, the digital economic environment, emerging consumer demand, and the application of innovative technology; the internal factors were the digitalization of cultural resources, flexible manufacturing, digital marketing and promotion, online interactive services, and virtual platform facilities. Each factor was found to contribute to virtual agglomeration through different internal mechanisms. This study’s findings have theoretical and practical value for cultivating the modes of virtual agglomeration within creative industries.

Influence of Pedestrian Number on Vibration Serviceability of Footbridge

2014 ◽  
Vol 1049-1050 ◽  
pp. 378-382
Author(s):  
Ju Bing Zhang ◽  
Shao Xia Zhang ◽  
Ying Zou
Keyword(s):  
Finite Element ◽  
Flow Simulation ◽  
Steel Structure ◽  
Element Model ◽  
Simulation Software ◽  
Force Model ◽  
Social Force ◽  
Vibration Data ◽  
Finite Element Software ◽  
Vibration Serviceability

In recent years, the problem of the human-induced bridge vibration has attracted more and more concerns. In this paper , a steel structure footbridge named Shuang'an East in Beijing was taken as the example to collect the whole bridge vibration data and build the finite element model with the finite element software. In addition, this research changes the limitation of considering the pedestrian load as a whole with a traffic flow simulation software, which is based on social force model, applying to reflect the pedestrians' locations during walking. Comparing the simulation data with the the measured data, the vibration serviceability of footbridge will decrease with the increasing of the number of the pedestrians. The analysis results will provide reference for the dynamic characteristic of similar structures.

The Frictionless Contact Problem for an Elastic Layer Under Gravity

1975 ◽  
Vol 42 (1) ◽  
pp. 136-140 ◽  
Author(s):  
M. B. Civelek ◽  
F. Erdogan
Keyword(s):  
Elastic Layer ◽  
Mixed Boundary ◽  
Contact Problems ◽  
Simple Problem ◽  
Frictionless Contact ◽  
Continuous Contact ◽  
Crack Problems ◽  
Contact Stress Distribution ◽  
Length Of Separation ◽  
Clamping Pressure

The paper presents a technique for solving the plane frictionless contact problems in the presence of gravity and/or uniform clamping pressure. The technique is described by applying it to a simple problem of lifting of an elastic layer lying on a horizontal, rigid, frictionless subspace by means of a concentrated vertical load. First, the problem of continuous contact is considered and the critical value of the load corresponding to the initiation of interface separation is determined. Then the mixed boundary-value problem of discontinuous contact is formulated in terms of a singular integral equation by closely following a technique developed for crack problems. The numerical results include the contact stress distribution and the length of separation region. One of the main conclusions of the study is that neither the separation length nor the contact stresses are dependent on the elastic constants of the layer.

A continuous contact force model for impact analysis

2022 ◽  
Vol 168 ◽  
pp. 108739
Author(s):  
Jie Zhang ◽  
Xu Liang ◽  
Zhonghai Zhang ◽  
Guanhua Feng ◽  
Quanliang Zhao ◽  
...  
Keyword(s):  
Contact Force ◽  
Impact Analysis ◽  
Force Model ◽  
Continuous Contact ◽  
Contact Force Model

Modeling Expected Wear in Revolute Joints With Clearance in Multibody Mechanical Systems

2007 ◽  
Author(s):  
P. Flores ◽  
J. Ambro´sio ◽  
J. C. P. Claro ◽  
H. M. Lankarani
Keyword(s):  
Research Work ◽  
Contact Forces ◽  
Joint Surface ◽  
Force Model ◽  
Wear Model ◽  
Continuous Contact ◽  
Revolute Joints ◽  
Sliding Motion ◽  
Impact Forces ◽  
Contact Impact

The main goal of this work is to develop a methodology for studying and quantifying the wear phenomenon in revolute clearance joints. In the process, a simple model for a revolute joint in the framework of multibody systems formulation is presented. The evaluation of the contact forces developed is based on a continuous contact force model that accounts for the geometrical and materials properties of the colliding bodies. The friction effects due to the contact in the joints are also represented. Then, these contact-impact forces are used to compute the pressure field at the contact zone, which ultimately is employed to quantify the wear developed and caused by the relative sliding motion. In this work, the Archard’s wear model is used. A simple planar multibody mechanical system is used to perform numerical simulations, in order to discuss the assumptions and procedures adopted throughout this work. Different results are presented and discussed throughout this research work. From the main results obtained, it can be drawn that the wear phenomenon is not uniformly distributed around the joint surface, owing to the fact that the contact between the joint elements is wider and more frequent is some specific regions.

Characterization of the Damping Coefficient in the Continuous Contact Model

2019 ◽  
Author(s):  
Mohammad Poursina ◽  
Parviz E. Nikravesh
Keyword(s):  
Contact Force ◽  
Analytical Formula ◽  
Deformation Characteristic ◽  
Contact Model ◽  
Damping Coefficient ◽  
Force Model ◽  
Separation Condition ◽  
Continuous Contact ◽  
Continuous Contact Model ◽  
The Impact

Abstract This article presents an analytical formula to characterize the damping coefficient in a continuous force model of the direct central impact. The contact force element consists of a linear damper which is in a parallel connection to a spring with Hertz force-deformation characteristic. Unlike the existing models in which the separation condition is assumed to be at the time at which both zero penetration (deformation) and zero force occur, in this study, zero contact force is considered as the separation condition. To ensure that the continuous contact model obtains the desired restitution, an optimization process is performed to find the damping coefficient. The numerical investigations show that the damping coefficient can be analytically expressed as a function of system’s parameters such as the effective mass, penetration speed just before the impact, Hertz spring constant, and the coefficient of restitution.

Nonlinear Hydrodynamic Forces on Flexible Structures: A Combined-Force Model

2004 ◽  
Vol 126 (1) ◽  
pp. 78-83 ◽  
Author(s):  
Iftekhar Anam ◽  
Jose M. Roesset
Keyword(s):  
Flexible Structures ◽  
Nonlinear Problems ◽  
Nonlinear Effects ◽  
Diffraction Theory ◽  
Computational Effort ◽  
New Method ◽  
Force Model ◽  
Order Difference ◽  
The Individual ◽  
Better Than

A new combined-force method is suggested to approximate the second-order difference frequency forces from diffraction theory (Φ2 theory) with less computational effort. The new method is formulated by combining two limiting cases of the Φ2 theory; i.e., Newman’s approximation and the slender Φ2 theory. Numerical results show that the new method reproduces the individual nonlinear effects of the Φ2 theory better than the existing approximations. Results of this work also show the limitations of Morison’s equation as the slender-body counterpart of the diffraction theory for nonlinear problems.

Sign in / Sign up

Export Citation Format

Share Document