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Pushbelt CVT Operation:
With a pushbelt CVT, the whole drivetrain including the engine of a passenger car can operate in an optimal state at any time. Dynamic simulations of the system have been investigated by Bosch Transmission Technology B.V. and the Institute of Applied Mechanics of the Technische Universität München. The underlying spatial transient mathematical model is challenging because of numerous contacts (~5500) and a large degree of freedom (~3500). In order to avoid high numerical stiffnesses and to encourage an efficient as well as a robust numerical treatment, a nonsmooth contact description using time-stepping schemes has been chosen and implemented in MBSim. Validation with measurement data has shown that a new level of detail in CVT modeling has been achieved.

1 Million Bodies:
Simulating one million individual rigid bodies is an extremely complex problem both in terms of numerical complexity and associated the hardware requirements. In order to advance the simulation by one timestep a Cone Complementarity Problem (CCP) with a dimension of 12 million is solved several times iteratively, resulting in the solution for the timestep. The solution of such a large system is not possible with CPU bassed algorithms in any reasonable amount of time. Therefore, This simulation was performed using the Chrono::Engine physics engine leveraging GPU computing for the collision detection and solution of the CCP. With a time step of 0.01 second and 1,024,000 rigid body particles, this 40 second long simulation took 65 hours on a machine with an NVIDIA TESLA C1060 GPU.

Fast Continuous Collision Culling:
We present a novel culling algorithm to perform fast and robust continuous collision detection between deforming volume meshes. This includes a continuous separating axis test that can conservatively check whether two volume meshes overlap during a given time interval. Moreover, we present efficient methods to eliminate redundant elementary tests between the features (e.g., vertices, edges, and faces) of volume elements (e.g., tetrahedra). Our approach is applicable to various deforming meshes, including those with changing topologies, and efficiently computes the first time of contact. We are able to perform inter-object and intra-object collision queries in models represented with tens of thousands of volume elements at interactive rates on a single CPU core. Moreover, we observe more than an order of magnitude performance improvement over prior methods.

May 25, 2011