Dear Friends,
Consider a 3D plate with a crack modeled in ABAQUS. We put a strip of cohesive elements along the crack surface, to model the propagation of crack. At the first step, I put a big values for crack propagation criteria of the cohesive element, so there will be no propagation. Then, I obtained the displacement-time or stress-time curve for this model.
The problem is, when I compare displacement-time curve for model with and without the cohesive element, the model with cohesive element shows smaller values in terms of displacement/stress magnitude, even we done't have any crack propagation. Can anybody explain to me why?
Thanks,
Dear Mohamed
The cohesive model define the elasticity limit but for crack you have any elasticity and you need another model take account the decrease of mechanical parameters with crack
You might find the following paper useful: "Some investigations about the tensile strength and the desiccation process of unsaturated clay"
Best regards
Article Some investigations about the tensile strength and the desic...
Dear Houcem,
Thanks for your comment. I need to use Abaqus cohesive element inside of my model. The parameters are fixed. So, I only need to find out why that behavior happened!
Dear Jorge,
The loading is a dynamic fatigue-like type, by prescribing forces.
The displacement/stress are from the crack tip. By having a dynamic loading, the displacement-time curve has an oscillatory behavior, so by magnitude I meant the average of the maximum value of the displacement/stress during the whole analysis.
Could you give more info on the "initial stiffness" for the cohesive elements? Where can I set required parameters for this?
Is there any difference for the explicit analysis?
I set the initial thickness of cohesive elements equal to zero. You said about selecting a big value for the initial stiffness, is there any limit for that or I can put as much as I want?
Regards,
Mohammad
Dear Jorge,
Thanks a lot for your explanations. Let me do my calculations and update my model, then I'll let you know about the results.
Regards,
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