Abaqus Concrete Structure Modeling | Practical Examples (Part 4)

Workshop-1: Damage Investigation of the concrete-filled double skin steel tube in dynamic bending

This workshop examines the damage behavior of a concrete-filled double-skin steel box subjected to dynamic bending in Abaqus. The inner and outer steel boxes are represented as three-dimensional shell elements, while the concrete core is modeled as a three-dimensional solid element.

Concrete-filled double-skin tube (CFDST) columns represent an innovative approach to column construction. These columns consist of two concentrically aligned steel hollow sections, with concrete cast in the space between them. The inner and outer steel sections do not necessarily have to share the same cross-sectional shape. This study specifically focuses on CFDST columns constructed using circular steel hollow sections.

To characterize the behavior of steel, an elastic-plastic material model incorporating a ductile damage criterion is employed to predict damaged regions under loading. For the concrete, the Johnson-Holmquist model is utilized, as it is well-suited for both dynamic and quasi-static simulations. A dynamic explicit step is selected for the analysis due to its effectiveness in handling impact-related deformations.

Contact interactions are modeled using a surface-to-surface approach with defined properties such as friction coefficient, shear stress limits, and elastic limits. A general contact algorithm is applied to the remaining interaction domains. The lower rigid parts are assigned fixed boundary conditions, while a displacement-controlled load is applied to the upper rigid part. A refined mesh is necessary to accurately capture damage and crack propagation.

Following the simulation, results such as damage distribution in steel and concrete, stress and strain fields, and the force-displacement response can be obtained.

Workshop-2: Simulation of composite column(steel beam and concrete) in cyclic loading

Workshop-3: Failure analysis of concrete cover separation in FRP plated in RC beam

This workshop focuses on the finite element modeling of reinforced concrete beams externally strengthened for flexural performance using side-bonded CFRP laminates in Abaqus. The concrete beam and epoxy adhesive are represented as three-dimensional solid elements, while the CFRP laminate is modeled as a three-dimensional shell element, and the reinforcement bars are defined as three-dimensional wire elements.

Recent advancements in material science have facilitated the development of high-performance composites, particularly fiber-reinforced polymer (FRP) sheets and plates. These composites consist of high-strength continuous fibers embedded in a polymer matrix, providing exceptional mechanical properties such as a high strength-to-weight ratio, resistance to creep and fatigue, and durability in corrosive or harsh environments.

The material behavior is defined using an elastic model combined with the Concrete Damaged Plasticity (CDP) model for concrete, an elastic-plastic model for steel reinforcement, Hashin’s damage criterion for CFRP, and a traction-separation law for the adhesive layer. A general static step is selected for the analysis. Perfect contact is assumed between the concrete and adhesive, as well as between the adhesive and CFRP. Additionally, a general contact algorithm incorporating friction is applied to model interactions among all components. Proper boundary conditions are assigned to the rigid supports. A refined mesh is necessary to improve the accuracy of the results.

Following the simulation, various output results can be obtained, including damage distribution in the CFRP laminate, tensile and compressive damage in the concrete, and failure of the adhesive layer.