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Motion analysis

Question asked by Srikumar Gopalakrishnan on May 25, 2011

I am working on motion analysis of solid works. I am working on solid - solid contact in solid works. I am interested to generate contact forces in solid works. I am working on elastic properties in solid-solid to contact.

 

I am studying the contact force variation with respect to these parameters.

 

I am running a material model with dynamic coefficient of friction as 0.25 and static friction as 0.3

 

For determining the contact forces I used a restitution coefficient method to determine contact forces. The model runs correctly and I am able to get the contact forces in this methodology, with restitution coefficient method with default value of 0.15 and values changed to 0.1 and also changed to 0.09

 

But when I use impact method in solid works with stiffness value 100000, exponent 1.5 and damping value of 49 (all three values namely stiffness, exponent and damping value as default value) my analysis experience convergence issue and it returns an error code.  

 

How are these restitution coefficient and impact method, I found that there is a relation between restitution coefficient and damping value used ?, is that right.

 

How to determine the contact stiffness value in this case of the model ?,

 

I used a contact stiffness value based on bulk modulus , square of area and volume and contact coefficient value.

 

contact stiffness = (0.1*bulkmodulus*contact area*contact area)/volume of contacting bodies

 

Is this the way the contact stiffness value in solid works motion analysis is calculated?

 

I also varied the stiffness value in solid-solid contact based on solid works help manual by giving a force to the model and determining the displacement and getting the contact stiffness from this method. Even in this case the solution is diverging

 

Please let me know

 

How the contact stiffness is calculated in solid works motion analysis ?

 

when will the contact forces obtained from restitution coefficient method and contact forces obtained from impact method will be same ?

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