I am facing a problem with the simulation of the precast concrete beam with prestressing. Typically, a precast beam would be fabricated in the factory with prestressing tendons (precambering) to cater for the deflection due to long-span. That means the prestressing force resulted in bending moment in the precast beam portion only. It's not like post-tensioned beam where the prestressing is applied after the entire beam section has been formed. Therefore, to properly model the trapped in stress and strain in precast concrete beam, I need to model them in different stages.
What I am currently doing is to use the Interface_Springback keyword to write out the dynain file for the following analysis. This helps me to map over the deformed shape with the topping concrete mesh.
However, the dynain file only captures the initial solid and beam element stress. No strain would be copied over. So the concrete's compressive strain would be underestimated?
So I am wondering whether this is correct for the following analysis?
If I only copy over the initial stress and the deformed geometry, it will start with zero strain for all the elements.
Another option is I can copy over the initial stress of the precast concrete elements (with the beam elements for PT) but kept the initial geometry and then let the precast concrete elements deform under the initial stress. But that would cause the topping concrete elements to deform together which is not true.
You need to capture stresses and strains, including shrinkage, creep and relaxation effects at each loading stage. This may require old fashioned addition in a spreadsheet.