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CosmosMotion - leaf spring model 2007/08?

Question asked by 1-8WP1OO on Oct 8, 2008
Latest reply on Jan 7, 2009 by 1-8WP1OO
The multibody dynamics engine 2005 has been an excellent and accessible simulation platform for CosmosMotion under SolidWorks. For example in the SW2007 software a leaf spring could be readily modelled using five beam elements interconnected with spherical joints and subsequently constraint by expressions. This is not the case with SW2008 and I am struggling to find a suitable work around.

A pair of spherical joints in a quarter leaf (eg. forward of the axle) are constrained by adding an expression to one joint's rotations to mimiv the other. A bush is also added at one of these joints to provide the overall spring element on that half of the leaf spring (on one side of the vehicle). A vertical preload is used to support the initial geometry of the springs under the weight of the vehicle.

After initial oscillations due to some preload error the attached video clip shows first an increase in the vertical load, a roll moment, a lateral force and then ABS braking torques applied to the axle.

Using these techniques we have been able to build an accurate full vehicle model of a truck using CosmosMotion and are in the process of finally validating the model with circuit testing of a full scale prototype vehicle. However, since September 2007 we have been struggling with the format of the expressions in 2007 and now the upgrade limitations 2008.

Does anyone have any suggestions.

Thank you.

~Carl

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