Papers abstract:

This paper describes the finite element method using ABAQUS to model the axial compressive behavior of inclined, tapered, and straight–tapered–straight (STS) concrete-filled steel tubular stub (CFST) columns with square hollow sections. The accuracy of the numerical model was verified by comparing the numerical predictions with an experimental study of the 200×200×3.75 RHS filled with C60 concrete with an inclined angle of 0–9° and a tapered angle of 0–4°. The results show that the compressive behaviors, load vs. strain relationship, and failure mode predicted by the numerical simulations were agreeable with experimental results. After the validation, a parametric study was performed with three typical steel hollow sections (200×200×3.75 RHS, 300×300×6.3 RHS, and 400×400×8.0 RHS) and extended the inclined angle and tapered angle to 0–15° and 0–12°, respectively. The parametric study highlights some of the behavior observed in the test and extends the application range. In addition, a reduction factor for calculating the axial capacity of this form of CFST columns is proposed.

Product Overview:
This tutorial provides a step-by-step guide to simulating tapered CFST columns under axial compression, based on experimental and numerical data from Lam et al. (2012). Key simulation steps include:

• Geometry creation: Tapered column with smaller top and larger bottom sections.
• Material assignment: Concrete Damaged Plasticity (CDP) for concrete and elastic-plastic steel.
• Interaction setup: Frictional contact (µ = 0.3) for dynamic analysis; Tie Constraint for static analysis.
• Boundary conditions: Fixed bottom plate and displacement-controlled top loading.
• Meshing & solving: Medial axis meshing with Explicit (dynamic) and Standard (static) solvers.
• Post-processing: Force-displacement curves and damage variable extraction (DAMAGEC, DAMAGET).

In this tutorial, tapered CFST columns are simulated, according to data from the work of Lam et al.