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ADAMS/Car Leaf Spring Editor: Using Inputs based on Design Height Geometry

jsph_inc

Hello,

I am using the Leaf Spring Editor to create a leaf spring in ADAMS/Car. I have CAD of the leaf spring in the design height. CAD of the leaf spring in the unloaded position is not available.

If I use this CAD for the leaf X-Z locations, is there a way to account for it being in design height (ADAMS expects these locations to be the unloaded position)? 

I've been trying to compensate for this through the "Rise to Curb" and "Reference Marker to Leafpack" values but no luck so far. After equilibrium the leaf springs have flattened which is not realistic.

Thanks for any help!

j.

  • 0

    Hi 

    The Leaf Spring Editor expects the X and Z coordinates to represent the leaf spring in its free (unloaded) state. During the makeleaf process, the spring is taken through three stages: free shape → rise-to-curb position (where the bushings are zeroed) → design position.

    If the geometry entered in the editor already represents the spring at design height, the model effectively starts from a pre-deflected condition. When vehicle weight is subsequently applied, the spring will deflect even further, resulting in additional flattening.

    Note- The Rise to Curb and Reference Marker to Leafpack parameters are only used to define the preload sequence. They do not convert the input geometry from one load condition to another.

    Possible approaches:

    1. Estimate the free shape geometry by offsetting the CAD Z-coordinates based on the expected deflection under the design load. This requires a reasonable estimate of spring stiffness and applied load.

    2. Adjust the Reference Marker height by specifying a slightly higher Z-value at the design-load condition. This can help compensate for the additional deflection and may be refined through a few iterations until the desired loaded shape is achieved.

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