Recommended concrete damage plasticity parameters and constitutive models for UHPC in ABAQUS

Abstract

In this study, the concrete damage plasticity (CDP) model of finite element (FE) software ABAQUS is validated and calibrated for ultra-high performance concrete (UHPC), for the first time. The CDP model is widely used for nonlinear FE analysis and was derived exclusively for normal strength concrete (NSC), hence the need for the current investigation. Inverse FE analysis at the material level was first performed on compressive UHPC cylinder and direct tension UHPC tests from literature, to evaluate the effects of primary CDP inputs, namely: dilation angle, eccentricity, stress ratio, and UHPC stress-strain (σ-ε) curves for compression and tension. Multiple analytical σ-ε models available for the compressive and tensile behavior of UHPC were evaluated within the framework of CDP and inverse FE analysis and were compared with experimental results. Best performing models including those with modifications proposed in this study were identified and recommended for future FE studies. Due to the UHPC material unique response and strong mesh size dependency, modelling its tensile behavior by a σ-ε approach was deemed inaccurate and thus recommended to be replaced with a stress-crack displacement alternative. A tensile strength-dependent revision term is proposed for the post-peak portion of the tensile stress-crack displacement relationship. A component level FE analysis, conducted on 22 structural members of various types (i.e. beams, slabs, columns), material and geometric characteristics, loading, and boundary conditions, confirmed the accuracy of proposed CDP inputs and the recommended modifications. The study results offer valuable guidance essential for the numerical analysis of UHPC members and structures.