scholarly journals Using Krylov subspace and spectral methods for solving complementarity problems in many-body contact dynamics simulation

2013 ◽  
Vol 95 (7) ◽  
pp. 541-561 ◽  
Author(s):  
Toby Heyn ◽  
Mihai Anitescu ◽  
Alessandro Tasora ◽  
Dan Negrut
Keyword(s):  
Spectral Methods ◽  
Krylov Subspace ◽  
Complementarity Problems ◽  
Contact Dynamics ◽  
Dynamics Simulation ◽  
Many Body ◽  
Body Contact

On the Numerical Solution of Many-Body Contact Dynamics Problems Formulated as Complementarity Problems

2012 ◽  
Author(s):  
Toby Heyn ◽  
Dan Negrut ◽  
Mihai Anitescu ◽  
Alessandro Tasora ◽  
David Lamb
Keyword(s):  
Numerical Solution ◽  
Equations Of Motion ◽  
Contact Dynamics ◽  
Many Body ◽  
Computational Accuracy ◽  
Body Contact ◽  
Granular Dynamics ◽  
Minimum Residual ◽  
And Performance ◽  
Dynamics Problems

This contribution is concerned with the modeling and simulation of many-body dynamics problems. In such problems, the solution method has to routinely handle millions of unknowns when, for instance, investigating granular dynamics related phenomena. Given the size of these problems, the scope of tractable applications may be limited by computational efficiency and/or computational accuracy. This scenario has been found to be the case when the equations of motion embed a differential variational inequality (DVI) problem that captures frictional/contact interactions between rigid and/or flexible bodies. As the size of the system increases, the speed and quality of the numerical solution may decrease. This contribution describes an alternative numerical method, called the Gradient Projected Minimum Residual or GPMINRES method, which demonstrates better scalability and performance (in terms of solution speed and accuracy) than methods commonly used to solve problems posed in this manner.

Multi-Body Contact Dynamics Analysis of Angular Contact Ball Bearing

2013 ◽  
Vol 444-445 ◽  
pp. 45-49
Author(s):  
Kun Feng Jin ◽  
Ting Qiang Yao
Keyword(s):  
Simulation Model ◽  
Model Simulation ◽  
Engineering Application ◽  
Dynamic Contact ◽  
Contact Dynamics ◽  
Dynamics Simulation ◽  
Contact Theory ◽  
Angular Contact Ball Bearing ◽  
Body Contact ◽  
Multi Body

The 3-D multi-body contact dynamics simulation model was built by ADAMS base on the Hertz contact theory and multi-body contact dynamics, which considered the dynamics relationship among the ball, ring and cage of the bearing. Considering the clearancesfrictions and loads, results that contained deformation and displacement of the bearing, trajectory of the CM of the cage and the dynamic contact force were obtained by means of the 3-D multi-body contact dynamics model simulation and statics calculation. The outcomes got from two different methods are consistent, so the 3-D multi-body contact dynamics simulation model has the positive significance on dynamic design and engineering application of the bearing.

A 2D Bristle Friction Force Model for Contact Dynamics Simulation

2009 ◽  
Author(s):  
Ou Ma ◽  
Jianxun Liang ◽  
Steven Fillmore
Keyword(s):  
Contact Point ◽  
Friction Model ◽  
Contact Dynamics ◽  
Dynamics Simulation ◽  
Contact Friction ◽  
Force Model ◽  
Tangential Plane ◽  
Friction Forces ◽  
Body Contact ◽  
Frictional Behavior

This paper describes a 2D bristle contact friction model which is capable of modeling and simulating frictional behavior in both sliding and sticking regimes occurring in general 3D rigid-body contact. The model extends the 1D integrated bristle friction model to a 2D space by allowing the “bristle spring” to not only stretch along the direction of the relative velocity but also rotate due to the direction change of the velocity or motion trend in the common tangential plane of the contacting surfaces involved at the contact point of interest. With such an extension, the resulting friction model can be readily used to compute 3D contact friction forces in both sticking and sliding regimes for a general 3D contact dynamics model working with a multibody dynamics simulation application. Several simulation examples are provided to demonstrate the effectiveness of the model for predicting the experimentally seen frictional behavior such as sticking, stickslip, and sliding.

Molecular Dynamics Simulation of Sputtering with Mmany-Body Interactions

1988 ◽  
Vol 100 ◽  
Author(s):  
Davy Y. Lo ◽  
Tom A. Tombrello ◽  
Mark H. Shapiro ◽  
Don E. Harrison
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Single Crystal ◽  
Low Energy ◽  
Dynamics Simulation ◽  
Embedded Atom Method ◽  
Many Body ◽  
Embedded Atom ◽  
Dynamics Simulations ◽  
Small Single Crystal

ABSTRACTMany-body forces obtained by the Embedded-Atom Method (EAM) [41 are incorporated into the description of low energy collisions and surface ejection processes in molecular dynamics simulations of sputtering from metal targets. Bombardments of small, single crystal Cu targets (400–500 atoms) in three different orientations ({100}, {110}, {111}) by 5 keV Ar+ ions have been simulated. The results are compared to simulations using purely pair-wise additive interactions. Significant differences in the spectra of ejected atoms are found.

ATOMISTIC SCALE SIMULATION OF TEXTURED SURFACES ON DRY SLIDING FRICTION

2013 ◽  
Vol 37 (3) ◽  
pp. 927-936 ◽  
Author(s):  
Ming-Yuan Chen ◽  
Zheng-Han Hong ◽  
Te-Hua Fang ◽  
Shao-Hui Kang ◽  
Li-Min Kuo
Keyword(s):  
Sliding Friction ◽  
Surface Texturing ◽  
Dynamics Simulation ◽  
Embedded Atom Method ◽  
Textured Surface ◽  
Textured Surfaces ◽  
Many Body ◽  
Embedded Atom ◽  
Modified Embedded Atom Method ◽  
Body Potential

Fe sliding on a Fe substrate with surface texturing is investigated using molecular dynamics simulation. The modified embedded-atom method many-body potential is used to describe the interaction of Fe atoms. The tribological properties of surface texturing during nanosliding are discussed. Results indicate that a textured surface has lower friction than that of a flat surface. In addition, a surface with parallel grooves has lower friction than that of a dimpled surface. Hence, surface texturing greatly affects friction.

scholarly journals TheαβTCR mechanosensor exploits dynamic ectodomain allostery to optimize its ligand recognition site

2020 ◽  
Vol 117 (35) ◽  
pp. 21336-21345 ◽  
Author(s):  
Wonmuk Hwang ◽  
Robert J. Mallis ◽  
Matthew J. Lang ◽  
Ellis L. Reinherz
Keyword(s):  
T Cell ◽  
Cellular Response ◽  
Complex Molecule ◽  
Immune Surveillance ◽  
Major Histocompatibility Complex Molecule ◽  
Contact Dynamics ◽  
Fine Tuning ◽  
Dynamics Simulation ◽  
Cell Repertoire ◽  
Catch Bond

EachαβT cell receptor (TCR) functions as a mechanosensor. The TCR is comprised of a clonotypic TCRαβligand-binding heterodimer and the noncovalently associated CD3 signaling subunits. When bound by ligand, an antigenic peptide arrayed by a major histocompatibility complex molecule (pMHC), the TCRαβhas a longer bond lifetime under piconewton-level loads. The atomistic mechanism of this “catch bond” behavior is unknown. Here, we perform molecular dynamics simulation of a TCRαβ-pMHC complex and its variants under physiologic loads to identify this mechanism and any attendant TCRαβdomain allostery. The TCRαβ-pMHC interface is dynamically maintained by contacts with a spectrum of occupancies, introducing a level of control via relative motion between Vα and Vβ variable domains containing the pMHC-binding complementarity-determining region (CDR) loops. Without adequate load, the interfacial contacts are unstable, whereas applying sufficient load suppresses Vα-Vβ motion, stabilizing the interface. A second level of control is exerted by Cα and Cβ constant domains, especially Cβ and its protruding FG-loop, that create mismatching interfaces among the four TCRαβdomains and with a pMHC ligand. Applied load enhances fit through deformation of the TCRαβmolecule. Thus, the catch bond involves the entire TCRαβconformation, interdomain motion, and interfacial contact dynamics, collectively. This multilayered architecture of the machinery fosters fine-tuning of cellular response to load and pMHC recognition. Since the germline-derived TCRαβectodomain is structurally conserved, the proposed mechanism can be universally adopted to operate under load during immune surveillance by diverseαβTCRs constituting the T cell repertoire.

Effect of Size on the Mechanical Properties of Rh-20at%Pd Nanowire

2011 ◽  
Vol 403-408 ◽  
pp. 1173-1177
Author(s):  
Jamal Davoodi ◽  
Mohammad Javad Moradi
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Bulk Modulus ◽  
Elastic Constants ◽  
Constant Pressure ◽  
Young Modulus ◽  
Dynamics Simulation ◽  
Many Body ◽  
Temperature Constant ◽  
Body Potential

The aim of this research was to calculate Yong modulus, Bulk modulus and the elastic constants of Rh-20at%Pd (atom percent) nanowire. The molecular dynamics simulation technique was used to calculate the mechanical properties at constant temperature, constant pressure ensemble. The cohesive energy of the model nanowire systems was calculated by Quantum Sutton-Chen many body potential. The temperature and the pressure of the system were controlled by Nose-Hoover thermostat and Berendsen barostat, respectivly. In addition effects of the diameter of nanowire on the mechanical properties were studied. The obtained results show that, when the diameter of Rh-Pd nanowire increase, elastic constants, bulk modulus and Young modulus all increase, and when the diameter reaches about 5.5 nm, the properties began to level off and remain constant.

Linearization and Model Reduction of Contact Dynamics Simulation

2011 ◽  
Author(s):  
Jianxun Liang ◽  
Ou Ma ◽  
Caishan Liu
Keyword(s):  
Model Reduction ◽  
Multibody Systems ◽  
Reduction Method ◽  
Contact Dynamics ◽  
Dynamics Simulation ◽  
Dynamics Model ◽  
Time Step ◽  
Reduction Techniques ◽  
Proposed Model ◽  
Simulation Time

Finite element methods are widely used for simulations of contact dynamics of flexible multibody systems. Such a simulation is computationally very inefficient because the system’s dimension is usually very large and the simulation time step has to be very small in order to ensure numerical stability. A potential solution to the problem is to apply a model reduction method in the simulation. Although many model reduction techniques have been developed, most of them cannot be readily applied due to the high nonlinearity of the involved contact dynamics model. This paper presents a solution to the problem. The approach is based on a modified Lyapunov balanced truncation method. A numerical example is presented to demonstrate that, by applying the proposed model reduction method, the simulation process can be significantly speeded up while the resulting error caused by the model reduction is still within an acceptable level.

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