concrete orthotropy induced by limited tensile strength (part 2)

A lot of cracking will arise in the high beam. Every concrete quad element has four integration points. Each integration point may have up to two cracks. Quite a rough discretization with 176 quad elements is used for the concrete body. Actually 622 smeared cracks occur with a prescribed final displacement of 4 cm. This corresponds to 44 % of potential cracking.

The following behavior can be seen: A crack occurs in some area A upon a loading increment whereby reaching the concrete’s tensile strength and basically bringing the material into the softening range. This turns out to be a distinct modification of the structural system.

Such a modification leads to a redistribution of stresses. The cracked area is relieved and another area B gains stresses up to the concrete’s tensile strength with the same loading or prescribed displacement, respectively. A further smeared crack occurs in area B, i.e. another distinct modification of the structural system inducing a further redistribution of stresses.

Actually a cascade of aftereffects or chain reaction occurs due to the initial cracking in area A and the high beam’s stress redistribution potentials. Some Cracks which were in the softening branch come into the unloading branch. Crack closures occur in a few cases. Other cracks open beyond the critical crack width without crack tractions and fully exploited crack energy.

What does this mean for the computational model? To be continued, stay tuned.

(Part 1)

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