Simulations with superquadric particles
Description
This text describes how to perform “SUPERQUADRIC” simulations in Aspherix®.
Introduction
“SUPERQUADRIC” simulations allow Aspherix® to use superquadric bodies as particles.
Detailed description
The overall simulation structure stays the same for SUPERQUADRIC simulations as used for standard Aspherix® simulations. In order to create a SUPERQUADRIC simulation based on an existing case you have to perform following steps:
To define new SUPERQUADRIC particles use the particle_template superquadric
Performance
The SUPERQUADRIC model uses the framework of Aspherix®. Therefore, the parallel scalability is linear as Aspherix® itself. Compared to standard Aspherix®, the calculation of contact points is computational expensive for superquadric bodies, which leads to a lower maximum number of particles per processor.
The contact detection algorithm that is employed for superquadrics [1] involves a large number of mathematical operations, such as exponentiation to the power of blockiness, for the calculation of the shape functions, their gradient and hessian matrices. In floating point arithmetics, these operations can be performed much faster when the exponent (the blockiness parameter) can be represented as an integer instead of a double data type, and Aspherix® takes that into consideration. Thus, the contact detection algorithm and therefore the superquadrics simulations are much faster when the blockiness parameter is an integer.
Tutorial cases
A tutorial cases demonstrates the usage of convex particles:
examples/solver/particle_shape/superquadric
Questions?
If any questions remain, do not hesitate to contact us.