Small sliding error message

[Ross_Eng]

Hi all,

Short of it is that I am getting "***ERROR: SMALL SLIDING CONTACT CAN SPAN MORE THAN ONE STEP BUT IT CAN ONLY BE DEFINED IN THE FIRST STEP OF AN ANALYSIS" when this contact is defined in the first step (but not the initial step).

I am currently undertaking my MEng project and am looking to simulate a projectile impact in Abaqus explicit. However, in this case, I am investigating any effects that the constraining of the specimen will have on the deformations observed before deciding on a mounting method for the specimen.

Due to the nature of the event I am simulating (1/2" ball bearing impacting 3mm S355 steel plate at ~340 m/s) I am using the explicit solver. Annoyingly, the bolt preload is not able to be applied as simply as in an implicit simulation. Since I am relatively new to Abaqus I deemed it most effective to perform an implicit sim and import the predefined field state of the bolt to my explicit model.

I have been working my way through the errors until this one. There is very little information online about this and my relative inexperience could be causing me to miss a simple solution (like moving the contact definition to a different part of the input file. Can this be done?).

Any advice (even better modelling practice) is much appreciated.

If any other info is required or desired, just let me know.

Ross.

 

[Mustaine3]

Define the contact in the initial step.

Bolt preload can be added in Explicit through a workaround with connector elements. Just cut out a small portion of the bolt shaft and use two coupling to place a connector (type=translator, e.g.) in between. In the first explicit step you can add the preload into the connector and lock the displacement in the second step. Make sure to use amplitudes and mass scaling to get a fast quasi-static solution for that step

 

[Ross_Eng]

Cheers for your reply.

When you say to define it in the initial step, there doesn't seem to be one stated as the initial step. The first one that I have defined is the "BEFORE_IMPACT" step, which i created after the initial one. If i move the contacts above the start of the BEFORE_IMPACT step, does this apply them to the initial step? I have moved them to after my interaction properties card. Will try running again like this once another sim is finished.

I will attempt to get this working first. Failng this, I will explore the connector elements solution you suggested. Seems slightly simpler than importing the implicit sim results. Thanks for your help.