3D End Notched Flexure test (Mode II fracture) using cohesive elements

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I’m using ABAQUS to create a 3D End Notched Flexure test. Two beams with a cohesive element interface and a pre-crack make up the end notched flexure specimen. A three-point bend design is used in the test. For the ENF arms, solid components (C3D8) are used, and the interface is modeled with finite thickness cohesive elements (COH3D8). The ends of the specimen are pinned and roller conditions are applied, and a displacement is applied in the middle.
Within the first few increments, the analysis fails. The force residuals haven’t converged or the cohesive parts have severe distortion, according to the error message. I tried both a static general step and a dynamic implicit step with a quasi-static specification. Refinement of the mesh and reduction of the increment size have had no effect. It didn’t help to use cohesive contact instead of cohesive elements.
Can someone offer suggestions about how to fix these issues?
Thank you very much.

CAE Assistant in Social Media Abaqus ResearchGate flexure test cohesive elements mode 2 fracture

Training Expert asked 11 months ago

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Answers (1)

Best Answer

Hi,

When you have damage initiation and progressive damage in your analysis, whether there is “cohesive” in your analysis or not, you should use the Explicit solver to avoid convergence issues. Refer to this link: https://caeassistant.com/blog/abaqus-standard-or-abaqus-explicit/

Moreover, I suggest using cohesive contact instead of the cohesive element.

Also, check the link below. You will find useful tips and tricks about cohesive analysis.

https://caeassistant.com/product/implementation-of-cohesive-by-interaction-element-base-methods-in-abaqus/