Predictive and Diagnostic Analyses

This sub-task focuses on the development of three-dimensional (3D) non-linear finite element models for the tested specimens using ABAQUS. The objective of these models is to employ them as predictive analyses for the large-scale test and, once validated, as parametric tools for investigating design criteria and performance of systems not evaluated in the experimental program.

The 3D finite element model of the structural walls and wall assembly will be done by using ABAQUS’s brick elements to model the concrete and each reinforcement bar will be represented by sub-elements within the concrete continuum elements. ABAQUS’s concrete material model in ABAQUS will be used to model the constitutive behavior of the concrete. The concrete material model uses a two-parameter Drucker-Prager yield surface and a hydrostatic pressure dependent associated flow rule in compression and a crack detection surface and oriented-damaged elasticity concepts (smeared cracking) in tension. The ABAQUS material model will be initially calibrated through the simulation of material tensile and compressive tests on high-strength-concrete cylinders to evaluate the capability of the models to capture the measured stress-strain behavior. If the response is not appropriate, an ABAQUS user material model will be developed using the standard ABAQUS’s concrete model at its core. Steel modeling will use ABAQUS’s steel model based on standard J2 plasticity with strain hardening and Bauschinger’s effect.

In order to compare similar values from the FE model, the FE mesh will be created such that nodal deformations correspond to the actual instrumentation points on the test unit. The data form the test and from the model can then be reduced according to the same procedure. By creating such “virtual instruments” in the FE model it is possible to compare, test, and model results on an instrument-by-instrument basis. This allows prediction and assessment of the test unit behavior not only at a global level, but also on a local level.