Developing a dynamic model of a semi-trailer using a leaf spring suspension system.

Question

Hello everyone, I am attempting to build a dynamic model of a semi-trailer using a "slipper spring" suspension system.

This type of leaf spring assembly lacks a fixed shackle mount on the chassis; instead, the spring end simply slides against a contact surface on the chassis.

When constructing the dynamic model, I applied an "Impact" function between the leaf spring and the contact surface to handle the interaction. However, during a drop test, the model's behavior causes the spring and axle assembly to fly off the contact surface; I am currently applying the Impact function only in the Z-direction.

How should I model this to accurately reflect the actual motion of the semi-trailer? I would greatly appreciate your advice and solutions.

Thank you very much, and I look forward to your feedback.

HuanRose

GTT Adam · Accepted Answer

Hi @Dylan_HuanRose,

What type of constraints are you placing between these entities? Based on the image, you may have too many degrees of freedom still active. I would guess that either there need to be additional connections between the leaf springs and you chassis and/or the leaf spring slipper spring and the axle.

Also, how did you model this leaf spring assembly? Did you use the Vehicle Tools Extension's Leaf Spring Builder?

Hope this helps!

Adam Reid

Dylan_HuanRose · Accepted Answer

Thanks for the feedback. I am using the 2020 version and modeling the leaf springs using Leaf Spring Builder; since this type lacks spring eyes, the leaves simply slide against each other at their contact surfaces. I have constrained the leaf springs to the axle, while for the chassis, I applied an Impact constraint to prevent penetration.