In dynamic explicit analysis, cohesive interaction behavior under compressive force in Abaqus can be different compared to general static analysis due to the following reasons:

Time-dependent effects: Dynamic explicit analysis accounts for the time-dependent behavior of materials, considering inertial effects and the propagation of stress waves. Under compressive force, these dynamic effects can lead to different load transfer mechanisms and stress distributions within the cohesive zone compared to static analysis.

Strain rate sensitivity: Materials often exhibit strain rate sensitivity, meaning their mechanical properties can vary at different rates of deformation. Dynamic explicit analysis captures the high strain rates involved in dynamic loading conditions, and cohesive materials may exhibit different response characteristics, such as strain rate hardening or softening, compared to quasi-static or static loading.

Fracture and failure behavior: Dynamic explicit analysis is particularly suitable for capturing the initiation and propagation of cracks and fractures. Under compressive force, the cohesive zone can experience complex failure modes such as buckling, crushing, or spalling, which may not be adequately captured in general static analysis. The dynamic nature of the analysis allows for a more realistic representation of fracture processes.

Rakesh Jakhar

Dear Rakesh,

Thank you for your thorough reply,

The problem with explicit analysis is that load-displacement results are highly mesh dependent.

I am modeling a layered concrete wall with cohesive interaction between the layers, and this wall is subjected to compressive axial load. If I do explicit analysis, the results are completely dependent on the mesh and as I decrease the element size, the strength and stiffness of wall increase. Should I choose the best mesh according to the closeness to the laboratory results?

On the other hand, static analysis does not provide good results and differs from experimental graph but it is not mesh dependent.

What do you recommend?

And does the cohesive element work at all under compressive force? because we just define tensile and shear stresses (tnn, tss, ttt) in Abaqus!

Thank you