Crack Propagation Analysis of Masonry Infill

[Minhajul_Bari]

Hi, I have modelled a masonry infill frame with a simplified micro-modelling manner (no model of morter; all bricks are extended with half thickness of mortar). I used surface base cohesive behaviour between the layers of brick (Surface-surface, small sliding). The analysis was performed in two steps. 1. Gravity Load, 2. Pushover Load. The hysteresis curve was found suitable, almost matching the experimental values.
However, I have faced a problem with crack propagation analysis. A few previous studies have used the VCCT Debonding option. However, I could not use it. The steps I followed:

[li]Creating new interaction property where I included only fracture criterion.[/li]
[li]Creating new interaction in Pushover Load steps where I used surface-surface, small sliding. I assigned previously defined fracture interaction.[/li]

However, the analysis could not run as I created 2 interactions (cohesive and fracture) using the same surfaces (top and bottom layer of brick) as master and slave.
My question is, what am I doing wrong, and how do I perform a crack propagation study in the interface where I have already defined cohesive behaviour?

 

[FEA way]

What error message did you get ? It should be defined within a single interaction property but it’s also important whether you are using Abaqus/Standard or Explicit. Check the documentation chapter Analysis —> Analysis Techniques —> Special-Purpose Techniques —> Fracture Mechanics —> Crack Propagation Analysis.

 

[Minhajul_Bari]

I used the dynamic implicit solution technique. Whenever I add fracture criterion to existing interaction, the following error arises.
[pre]*initial conditions, type=contact is only allowed for a contact pair with *cohesive behavior, eligibility=specified contacts
*initial conditions, type=contact is only allowed for a contact pair with *cohesive behavior, eligibility=specified contacts
The *debond keyword is not valid for contact surfaces with no prescribed *initial condition,type=contact
*fracture criterion keyword is ignored either due to errors while processing *debond or due to multiple specification of this option
Analysis Input File Processor exited with an error.[/pre]

 

[FEA way]

I would recommend just switching to dynamic explicit and following the aforementioned documentation chapter but you can also try fixing those errors starting from the first one (as it’s usually the root issue) - the messages are pretty informative.