Is it possible to implement cohesive contact property at the begining of Step-2 in Abaqus Explicit?

[JQKu]

Hi, everyone
I'm now simulating the cohesive contact of two spheres. The whole process has 2 steps. In the first step, 2 balls are contact which each other and deformed plasticly. In the second step, 2 balls are separated with adhesion. I create one interaction in Abaqus. The contact propertie in Step-1 is just general contact, while in Step-2 I assign an individual property of cohesive contact below the global property assignment. However, the results show that the contact force at the begining of the Step-2 is zero, the contact force is not continuous with the Step-1. Since more complex behaviors are to be simulated later, cohesive contact must not exist in the first step. Is there anyone konws how to deal with this problem? The INP file is attacthed.
Thanks!

 

[FEA way]

What is the actual goal of this analysis ? Is contact gradually established in the first step and then you want to separate these parts, breaking their adhesive connection ? If that's the case then it seems that cohesive behavior should be present in the first step too since these parts have to be glued together first before they can be separated.

 

[JQKu]

Thank you very much for your reply! In fact, what I want to simulate is like powder metallurgy. In the first stage, the cohesive effect between powder particles is not so obvious. There will be collisions or slippage between particles. The cohesion will be generated when the load reaches a certain level. Therefore, I would like to ask if there is any way to add a cohesive contact property in the middle of the loading and make the contact force continuous between the two steps.

 

[FEA way]

Have you considered using Abaqus/Standard instead of Explicit ? In Standard you could use contact pairs with cohesive behavior and this might give you more flexibility when it comes to activation and deactivation of this type of contact.

 

[JQKu]

Thank you very much for your suggestion. Maybe explicit analysis can't solve this problem well, I will try Abaqus Standard later.
Thanks!