Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : August 07, 2016 - August 10, 2016
The efficient contact modeling and algorithms for the precise mechanical systems are the most important issue and still challenging area in computational multi-body dynamics (MBD). Because many mechanical engineers demand to analyze the realistic contact behavior for the colliding or sliding contact problems, an efficient and accurate contact modeling and analysis algorithms are very important when analyzing the contact force distributions and the contact force variations for their precise mechanical systems. However, the existing contact methods and algorithms [1-3] were not enough to perform for the realistic contact behanior as much as expected becasue the existing contact algorithms have been developed based on the facetted triangle planes to represent the contact surfaces. When the contact surfaces are generated by the facetted triangles for contact analysis, the represented triangle contact surfaces have a geometrical error inherently. As a result, the contact force results are not enough accurate and smooth. In order to resolve this contact problem, Choi [4] suggested a new contact algorithm using a cubic spline surface representation method and related contact algorithms. Choi's contact algorithms used a compliant contact force model based on the Hertzian contact theory [1-5]. Then, to evaluate the accurate and smooth contact forces, the contact normal directions and the penetration depth between contact pair are calculated by using the cubic spline (Hermite) surface interpolation. But, this smooth algorithm was not still enough for the highly precise mechanism analysis such as a ball screw mechanical problem because there are many ball geometries and the shpae of balls should be represented very accurately. As a result, in this paper, the ball screw mechanical system are modelled and simulated with the new developed contact algorithms based on the analytical sphere geometry for the balls. Because, the screw geometry cannot be easily represented by the simple analytic equations, so it is applied the cubic spline surface interpolation method to the screw contact geometry based on the Choi's contact algorithms [4]. The new propesed contact algorithms are implemented and tested in RecurDyn [6] as a ‘Geo Sphere Contact' which can be applied to the contact problems between a sphere geometry and a complex general surface. Thereforce, the many balls to surface contact problems can be calculated more efficiently and faster by using the new contact algorithms. This new contact algorithm and its contact results will be introduced in this paper.
