Energetic consistency conditions for standard impacts

Glocker, Christian

doi:10.1007/s11044-013-9387-2

Cited by 45 publications

(12 citation statements)

References 56 publications

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“…3.3, appear in the equations of motion (18) through the generalized forces W (q)λ. The equations of motion (20) are fulfilled almost everywhere except at impact time instants t i for which velocity jumps occur due to impulsive contact forces. At these time instants, the velocities u(t) and accelerationsu(t) are undefined and the differential equations have therefore to be complemented by the impact equations…”

Section: Equations Of Motion and Impact Equationmentioning

confidence: 99%

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Simulation of rockfall trajectories with consideration of rock shape

Leine

Schweizer

Christen³

et al. 2013

Multibody Syst Dyn

133

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The aim of the paper is to develop a fully 3D simulation technique for rockfall dynamics taking rock shape into account and using the state-of-the-art methods of multibody dynamics and nonsmooth contact dynamics. The rockfall simulation technique is based on the nonsmooth contact dynamics method with hard contact laws. The rock is modeled as an arbitrary convex polyhedron and the terrain model is based on a high resolution digital elevation model. A specialized friction law for rockfall is proposed which allows for the description of scarring behavior (i.e., rocks tend to slide over the terrain before lift-off). The influence of rock geometry on rockfall dynamics is studied through two well-chosen numerical simulations.

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Section: Equations Of Motion and Impact Equationmentioning

confidence: 99%

“…Theoretically, such a preimpact state cannot be reached, however, it can occur in the numerics. Poisson's impact law, which is more elaborate as it uses two inequality complementarities, does not suffer from kinematic inconsistency [20].…”

Section: Impact Lawsmentioning

confidence: 99%

Simulation of rockfall trajectories with consideration of rock shape

Leine

Schweizer

Christen³

et al. 2013

Multibody Syst Dyn

133

View full text Add to dashboard Cite

show abstract

“…In the general case, we solve the least-squares problem given in table 1 to compute π in each interval. We assume that the local impact processes occurring at all participating points evolve in synchrony [42]. To assemble the least-squares problem, we must first classify each proximal point as either compressing, expanding or observing (i.e.…”

Section: (A) Simultaneity and Redundancymentioning

confidence: 99%

Making a meaningful impact: modelling simultaneous frictional collisions in spatial multibody systems

Sherman

Delp

2015

Proc. R. Soc. A.

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Impacts are instantaneous, computationally efficient approximations of collisions. Current impact models sacrifice important physical principles to achieve that efficiency, yielding qualitative and quantitative errors when applied to simultaneous impacts in spatial multibody systems. We present a new impact model that produces behaviour similar to that of a detailed compliant contact model, while retaining the efficiency of an instantaneous method. In our model, time and configuration are fixed, but the impact is resolved into distinct compression and expansion phases, themselves comprising sliding and rolling intervals. A constrained optimization problem is solved for each interval to compute incremental impulses while respecting physical laws and principles of contact mechanics. We present the mathematical model, algorithms for its practical implementation, and examples that demonstrate its effectiveness. In collisions involving materials of various stiffnesses, our model can be more than 20 times faster than integrating through the collision using a compliant contact model. This work extends the use of instantaneous impact models to scientific and engineering applications with strict accuracy requirements, where compliant contact models would otherwise be required. An open-source implementation is available in Simbody, a C++ multibody dynamics library widely used in biomechanical and robotic applications.

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“…(5). For more information about impacts, the reader is referred to [6,7]. The associated Newton-type impact inclusion can be formulated as…”

Section: Newton-type Impactsmentioning

confidence: 99%

Projective Jacobi and Gauss-Seidel on the GPU for Non-Smooth Multi-Body Systems

Nützi

Schweizer

Möller

et al. 2014

Volume 6: 10th International Conference on Multibody Systems, Nonlinear Dynamics, and Control

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Large-scale contact problems with impacts and Coulomb friction arise in the simulation of rigid body dynamics treated within the non-smooth contact dynamics approach using set-valued force and impact laws. In this paper the parallelization of two popular numerical methods for solving such contact problems on the GPU, being the projected over-relaxed Jacobi (JOR Prox) and projected Gauss-Seidel iteration (SOR Prox), is studied in detail. Performance tests for the parallel JOR and SOR Prox iterations are conducted and a speedup factor of up to 16, depending on the problem size, can be achieved compared to a sequential implementation. This work forms the stepping stone to the simulation of granular media on a computer cluster.

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Energetic consistency conditions for standard impacts

Cited by 45 publications

References 56 publications

Simulation of rockfall trajectories with consideration of rock shape

Simulation of rockfall trajectories with consideration of rock shape

Making a meaningful impact: modelling simultaneous frictional collisions in spatial multibody systems

Projective Jacobi and Gauss-Seidel on the GPU for Non-Smooth Multi-Body Systems

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