Simulation and Analysis of the Constraint Effects of Multi-Cavity Double Steel Plate Composite Walls

Multi-cavity double steel plate–concrete composite structures are composed of two layers of steel plates, accompanied by steel flanges, diaphragms, and a core of concrete. Thanks to their exceptional mechanical attributes, these structures have gained widespread adoption in the field of wind power engineering. The outer steel plates exert a notable confinement on the concrete filling. Nonetheless, there remains a lack of a constitutive model specifically tailored for concrete under confinement within the field of multi-cavity double steel plate–concrete composite structures. To bridge this gap, our research endeavor involved the creation of approximately 2000 shell–solid finite element models, leading to the derivation of a constitutive model for compressed confined concrete within such structures through regression analysis. Initially, theoretical evaluations were conducted to pinpoint the structural parameters potentially influencing confinement behavior. Thereafter, Abaqus shell–solid finite element models were formulated, and their accuracy was corroborated through experimental validations. By systematically adjusting parameters in batch modelling, regression analysis was conducted. Consequently, a constitutive model tailored for uniaxial compression of concrete in multi-cavity double steel plate–concrete composite structures (MDSCCS) was formulated. According to the results, the strength of confined concrete in MDSCCS can be enhanced by up to 23% under typical configurations, as observed in the benchmark model MDSCCS-1. The proposed regression-based confinement model demonstrates a prediction error of less than 15% in 97.8% of the 1342 finite element models that successfully converged in batch simulations.