Node-Dependent Kinematics Approach for Damage Analysis of Reinforced Concrete Structures

Modeling damage behavior in engineering structures is vital, but balancing computational efficiency and accuracy presents a significant challenge. This study introduces an advanced higher-order beam model incorporating a node-dependent kinematics approach, enhancing the efficiency of damage analysis in reinforced concrete structures. The proposed beam model is built in the framework of Carrera Unified Formulation, enabling a three-dimensional displacement field from a one-dimensional beam model via variable cross-sectional expansion functions. The node-dependent kinematics approach allows diverse cross-sectional kinematics at different nodes on the same beam element. Therefore, a customized approach can be applied where critical areas susceptible to localized damage utilize Lagrange polynomials and a Component-Wise approach for detailed analysis, while noncritical zones apply lower-order Taylor polynomials to reduce computational resources. The model incorporates a modified Mazars damage model for concrete and von Mises plasticity for steel. Four numerical assessments show that the proposed beam model with node-dependent kinematics can maintain accuracy while reducing degrees of freedom by 35%–60% compared to fully refined models with Lagrange polynomials. Moreover, the node-dependent kinematics only require simple adjustments to the cross-sectional kinematics as necessary without extensive mesh refinement. This scalability significantly simplifies the tuning process of beam models for practical applications.