Ansys Learning Forum Forums Discuss Simulation General Mechanical What are the working principles of Weak Springs? Reply To: What are the working principles of Weak Springs?

Surya Prakash
Ansys Employee

Weak Springs are automatically-created springs with just enough stiffness to constrain the rigid body motion.The Weak springs feature will create an imaginary ÔÇÿbounding boxÔÇÖ for each part, where springs at each of the 8 ÔÇÿcornersÔÇÖ are added for each part. So, if we imagine a ÔÇÿboxÔÇÖ covering each part, each node nearest to these 8 corners gets weak springs acting in the 3 orthogonal directions X, Y, and Z. The free ends of all the springs are constrained to ground. The spring stiffness is automatically calculated and defined by Mechanical to be a very low value.
This should not be used in place of actual boundary conditions, but rather a support feature that helps to prevent the rigid body motion present due to any imbalance in the loads and boundary conditions given. We should also make sure that they should not affect the analysis results by checking the reaction forces developed in the weak springs by using a probe>force reaction and scoping it to the weak springs in the solution tab. The resultant force reactions should be close to zero to get accurate results.
In addition to this, for the model that you have shared- you can use a symmetry model.
Thanks Surya
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