Multi-Body Dynamics: An Evolution from Constrained Dynamics to a Multi-Psysics Interactive Framework

2006 ◽  
pp. 273-298
Author(s):  
M. Teodorescu ◽  
S. Theodossiades ◽  
H. Rahnejat
Author(s):  
Joseph F. Boudreau ◽  
Eric S. Swanson

Specialized techniques for solving the classical many-body problem are explored in the context of simple gases, more complicated gases, and gravitating systems. The chapter starts with a brief review of some important concepts from statistical mechanics and then introduces the classic Verlet method for obtaining the dynamics of many simple particles. The practical problems of setting the system temperature and measuring observables are discussed. The issues associated with simulating systems of complex objects form the next topic. One approach is to implement constrained dynamics, which can be done elegantly with iterative methods. Gravitational systems are introduced next with stress on techniques that are applicable to systems of different scales and to problems with long range forces. A description of the recursive Barnes-Hut algorithm and particle-mesh methods that speed up force calculations close out the chapter.


2012 ◽  
Vol 8 (4) ◽  
pp. 660-664 ◽  
Author(s):  
K. T. Bates ◽  
P. L. Falkingham

Bite mechanics and feeding behaviour in Tyrannosaurus rex are controversial. Some contend that a modest bite mechanically limited T. rex to scavenging, while others argue that high bite forces facilitated a predatory mode of life. We use dynamic musculoskeletal models to simulate maximal biting in T. rex . Models predict that adult T. rex generated sustained bite forces of 35 000–57 000 N at a single posterior tooth, by far the highest bite forces estimated for any terrestrial animal. Scaling analyses suggest that adult T. rex had a strong bite for its body size, and that bite performance increased allometrically during ontogeny. Positive allometry in bite performance during growth may have facilitated an ontogenetic change in feeding behaviour in T. rex , associated with an expansion of prey range in adults to include the largest contemporaneous animals.


Author(s):  
H Lipkin ◽  
J Duffy

The theory of screws was largely developed by Sir Robert Stawell Ball over 100 years ago to investigate general problems in rigid body mechanics. Nowadays, screw theory is applied in many different but related forms including dual numbers, Plilcker coordinates and Lie algebra. An overview of these methodologies is presented along with a perspective on Ball. Screw theory has re-emerged after a hiatus to become an important tool in robot mechanics, mechanical design, computational geometry and multi-body dynamics.


2014 ◽  
Author(s):  
Michael S. Barton ◽  
David Corson ◽  
John Quigley ◽  
Babak Emami ◽  
Tanuj Kush

Author(s):  
Ruoxin Li ◽  
Qing Xiao ◽  
Lijun Li ◽  
Hao Liu

In this work, we numerically studied the steady swimming of a pufferfish driven by the undulating motion of its dorsal, anal and caudal fins. The simulations are based on experimentally measured kinematics. To model the self-propelled fish swimming, a Computational Fluid Dynamics (CFD) tool was coupled with a Multi-Body-Dynamics (MBD) technique. It is widely accepted that deformable/flexible or undulating fins are better than rigid fins in terms of propulsion efficiency. To elucidate the underlying mechanism, we established an undulating fins model based on the kinematics of live fish, and conducted a simulation under the same operating conditions as rigid fins. The results presented here agree with this view by showing that the contribution of undulating fins to propulsion efficiency is significantly larger than that of rigid fins.


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